1 /* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.widget; 18 19 import android.annotation.NonNull; 20 import android.util.ArrayMap; 21 import com.android.internal.R; 22 23 import java.util.ArrayDeque; 24 import java.util.ArrayList; 25 import java.util.Comparator; 26 import java.util.SortedSet; 27 import java.util.TreeSet; 28 29 import android.content.Context; 30 import android.content.res.TypedArray; 31 import android.graphics.Rect; 32 import android.os.Build; 33 import android.util.AttributeSet; 34 import android.util.Pools.SynchronizedPool; 35 import android.util.SparseArray; 36 import android.view.Gravity; 37 import android.view.View; 38 import android.view.ViewDebug; 39 import android.view.ViewGroup; 40 import android.view.ViewHierarchyEncoder; 41 import android.view.accessibility.AccessibilityEvent; 42 import android.widget.RemoteViews.RemoteView; 43 44 import static android.os.Build.VERSION_CODES.JELLY_BEAN_MR1; 45 46 /** 47 * A Layout where the positions of the children can be described in relation to each other or to the 48 * parent. 49 * 50 * <p> 51 * Note that you cannot have a circular dependency between the size of the RelativeLayout and the 52 * position of its children. For example, you cannot have a RelativeLayout whose height is set to 53 * {@link android.view.ViewGroup.LayoutParams#WRAP_CONTENT WRAP_CONTENT} and a child set to 54 * {@link #ALIGN_PARENT_BOTTOM}. 55 * </p> 56 * 57 * <p><strong>Note:</strong> In platform version 17 and lower, RelativeLayout was affected by 58 * a measurement bug that could cause child views to be measured with incorrect 59 * {@link android.view.View.MeasureSpec MeasureSpec} values. (See 60 * {@link android.view.View.MeasureSpec#makeMeasureSpec(int, int) MeasureSpec.makeMeasureSpec} 61 * for more details.) This was triggered when a RelativeLayout container was placed in 62 * a scrolling container, such as a ScrollView or HorizontalScrollView. If a custom view 63 * not equipped to properly measure with the MeasureSpec mode 64 * {@link android.view.View.MeasureSpec#UNSPECIFIED UNSPECIFIED} was placed in a RelativeLayout, 65 * this would silently work anyway as RelativeLayout would pass a very large 66 * {@link android.view.View.MeasureSpec#AT_MOST AT_MOST} MeasureSpec instead.</p> 67 * 68 * <p>This behavior has been preserved for apps that set <code>android:targetSdkVersion="17"</code> 69 * or older in their manifest's <code>uses-sdk</code> tag for compatibility. Apps targeting SDK 70 * version 18 or newer will receive the correct behavior</p> 71 * 72 * <p>See the <a href="{@docRoot}guide/topics/ui/layout/relative.html">Relative 73 * Layout</a> guide.</p> 74 * 75 * <p> 76 * Also see {@link android.widget.RelativeLayout.LayoutParams RelativeLayout.LayoutParams} for 77 * layout attributes 78 * </p> 79 * 80 * @attr ref android.R.styleable#RelativeLayout_gravity 81 * @attr ref android.R.styleable#RelativeLayout_ignoreGravity 82 */ 83 @RemoteView 84 public class RelativeLayout extends ViewGroup { 85 public static final int TRUE = -1; 86 87 /** 88 * Rule that aligns a child's right edge with another child's left edge. 89 */ 90 public static final int LEFT_OF = 0; 91 /** 92 * Rule that aligns a child's left edge with another child's right edge. 93 */ 94 public static final int RIGHT_OF = 1; 95 /** 96 * Rule that aligns a child's bottom edge with another child's top edge. 97 */ 98 public static final int ABOVE = 2; 99 /** 100 * Rule that aligns a child's top edge with another child's bottom edge. 101 */ 102 public static final int BELOW = 3; 103 104 /** 105 * Rule that aligns a child's baseline with another child's baseline. 106 */ 107 public static final int ALIGN_BASELINE = 4; 108 /** 109 * Rule that aligns a child's left edge with another child's left edge. 110 */ 111 public static final int ALIGN_LEFT = 5; 112 /** 113 * Rule that aligns a child's top edge with another child's top edge. 114 */ 115 public static final int ALIGN_TOP = 6; 116 /** 117 * Rule that aligns a child's right edge with another child's right edge. 118 */ 119 public static final int ALIGN_RIGHT = 7; 120 /** 121 * Rule that aligns a child's bottom edge with another child's bottom edge. 122 */ 123 public static final int ALIGN_BOTTOM = 8; 124 125 /** 126 * Rule that aligns the child's left edge with its RelativeLayout 127 * parent's left edge. 128 */ 129 public static final int ALIGN_PARENT_LEFT = 9; 130 /** 131 * Rule that aligns the child's top edge with its RelativeLayout 132 * parent's top edge. 133 */ 134 public static final int ALIGN_PARENT_TOP = 10; 135 /** 136 * Rule that aligns the child's right edge with its RelativeLayout 137 * parent's right edge. 138 */ 139 public static final int ALIGN_PARENT_RIGHT = 11; 140 /** 141 * Rule that aligns the child's bottom edge with its RelativeLayout 142 * parent's bottom edge. 143 */ 144 public static final int ALIGN_PARENT_BOTTOM = 12; 145 146 /** 147 * Rule that centers the child with respect to the bounds of its 148 * RelativeLayout parent. 149 */ 150 public static final int CENTER_IN_PARENT = 13; 151 /** 152 * Rule that centers the child horizontally with respect to the 153 * bounds of its RelativeLayout parent. 154 */ 155 public static final int CENTER_HORIZONTAL = 14; 156 /** 157 * Rule that centers the child vertically with respect to the 158 * bounds of its RelativeLayout parent. 159 */ 160 public static final int CENTER_VERTICAL = 15; 161 /** 162 * Rule that aligns a child's end edge with another child's start edge. 163 */ 164 public static final int START_OF = 16; 165 /** 166 * Rule that aligns a child's start edge with another child's end edge. 167 */ 168 public static final int END_OF = 17; 169 /** 170 * Rule that aligns a child's start edge with another child's start edge. 171 */ 172 public static final int ALIGN_START = 18; 173 /** 174 * Rule that aligns a child's end edge with another child's end edge. 175 */ 176 public static final int ALIGN_END = 19; 177 /** 178 * Rule that aligns the child's start edge with its RelativeLayout 179 * parent's start edge. 180 */ 181 public static final int ALIGN_PARENT_START = 20; 182 /** 183 * Rule that aligns the child's end edge with its RelativeLayout 184 * parent's end edge. 185 */ 186 public static final int ALIGN_PARENT_END = 21; 187 188 private static final int VERB_COUNT = 22; 189 190 191 private static final int[] RULES_VERTICAL = { 192 ABOVE, BELOW, ALIGN_BASELINE, ALIGN_TOP, ALIGN_BOTTOM 193 }; 194 195 private static final int[] RULES_HORIZONTAL = { 196 LEFT_OF, RIGHT_OF, ALIGN_LEFT, ALIGN_RIGHT, START_OF, END_OF, ALIGN_START, ALIGN_END 197 }; 198 199 /** 200 * Used to indicate left/right/top/bottom should be inferred from constraints 201 */ 202 private static final int VALUE_NOT_SET = Integer.MIN_VALUE; 203 204 private View mBaselineView = null; 205 206 private int mGravity = Gravity.START | Gravity.TOP; 207 private final Rect mContentBounds = new Rect(); 208 private final Rect mSelfBounds = new Rect(); 209 private int mIgnoreGravity; 210 211 private SortedSet<View> mTopToBottomLeftToRightSet = null; 212 213 private boolean mDirtyHierarchy; 214 private View[] mSortedHorizontalChildren; 215 private View[] mSortedVerticalChildren; 216 private final DependencyGraph mGraph = new DependencyGraph(); 217 218 // Compatibility hack. Old versions of the platform had problems 219 // with MeasureSpec value overflow and RelativeLayout was one source of them. 220 // Some apps came to rely on them. :( 221 private boolean mAllowBrokenMeasureSpecs = false; 222 // Compatibility hack. Old versions of the platform would not take 223 // margins and padding into account when generating the height measure spec 224 // for children during the horizontal measure pass. 225 private boolean mMeasureVerticalWithPaddingMargin = false; 226 227 // A default width used for RTL measure pass 228 /** 229 * Value reduced so as not to interfere with View's measurement spec. flags. See: 230 * {@link View#MEASURED_SIZE_MASK}. 231 * {@link View#MEASURED_STATE_TOO_SMALL}. 232 **/ 233 private static final int DEFAULT_WIDTH = 0x00010000; 234 235 public RelativeLayout(Context context) { 236 this(context, null); 237 } 238 239 public RelativeLayout(Context context, AttributeSet attrs) { 240 this(context, attrs, 0); 241 } 242 243 public RelativeLayout(Context context, AttributeSet attrs, int defStyleAttr) { 244 this(context, attrs, defStyleAttr, 0); 245 } 246 247 public RelativeLayout(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { 248 super(context, attrs, defStyleAttr, defStyleRes); 249 initFromAttributes(context, attrs, defStyleAttr, defStyleRes); 250 queryCompatibilityModes(context); 251 } 252 253 private void initFromAttributes( 254 Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { 255 final TypedArray a = context.obtainStyledAttributes( 256 attrs, R.styleable.RelativeLayout, defStyleAttr, defStyleRes); 257 mIgnoreGravity = a.getResourceId(R.styleable.RelativeLayout_ignoreGravity, View.NO_ID); 258 mGravity = a.getInt(R.styleable.RelativeLayout_gravity, mGravity); 259 a.recycle(); 260 } 261 262 private void queryCompatibilityModes(Context context) { 263 int version = context.getApplicationInfo().targetSdkVersion; 264 mAllowBrokenMeasureSpecs = version <= Build.VERSION_CODES.JELLY_BEAN_MR1; 265 mMeasureVerticalWithPaddingMargin = version >= Build.VERSION_CODES.JELLY_BEAN_MR2; 266 } 267 268 @Override 269 public boolean shouldDelayChildPressedState() { 270 return false; 271 } 272 273 /** 274 * Defines which View is ignored when the gravity is applied. This setting has no 275 * effect if the gravity is <code>Gravity.START | Gravity.TOP</code>. 276 * 277 * @param viewId The id of the View to be ignored by gravity, or 0 if no View 278 * should be ignored. 279 * 280 * @see #setGravity(int) 281 * 282 * @attr ref android.R.styleable#RelativeLayout_ignoreGravity 283 */ 284 @android.view.RemotableViewMethod 285 public void setIgnoreGravity(int viewId) { 286 mIgnoreGravity = viewId; 287 } 288 289 /** 290 * Describes how the child views are positioned. 291 * 292 * @return the gravity. 293 * 294 * @see #setGravity(int) 295 * @see android.view.Gravity 296 * 297 * @attr ref android.R.styleable#RelativeLayout_gravity 298 */ 299 public int getGravity() { 300 return mGravity; 301 } 302 303 /** 304 * Describes how the child views are positioned. Defaults to 305 * <code>Gravity.START | Gravity.TOP</code>. 306 * 307 * <p>Note that since RelativeLayout considers the positioning of each child 308 * relative to one another to be significant, setting gravity will affect 309 * the positioning of all children as a single unit within the parent. 310 * This happens after children have been relatively positioned.</p> 311 * 312 * @param gravity See {@link android.view.Gravity} 313 * 314 * @see #setHorizontalGravity(int) 315 * @see #setVerticalGravity(int) 316 * 317 * @attr ref android.R.styleable#RelativeLayout_gravity 318 */ 319 @android.view.RemotableViewMethod 320 public void setGravity(int gravity) { 321 if (mGravity != gravity) { 322 if ((gravity & Gravity.RELATIVE_HORIZONTAL_GRAVITY_MASK) == 0) { 323 gravity |= Gravity.START; 324 } 325 326 if ((gravity & Gravity.VERTICAL_GRAVITY_MASK) == 0) { 327 gravity |= Gravity.TOP; 328 } 329 330 mGravity = gravity; 331 requestLayout(); 332 } 333 } 334 335 @android.view.RemotableViewMethod 336 public void setHorizontalGravity(int horizontalGravity) { 337 final int gravity = horizontalGravity & Gravity.RELATIVE_HORIZONTAL_GRAVITY_MASK; 338 if ((mGravity & Gravity.RELATIVE_HORIZONTAL_GRAVITY_MASK) != gravity) { 339 mGravity = (mGravity & ~Gravity.RELATIVE_HORIZONTAL_GRAVITY_MASK) | gravity; 340 requestLayout(); 341 } 342 } 343 344 @android.view.RemotableViewMethod 345 public void setVerticalGravity(int verticalGravity) { 346 final int gravity = verticalGravity & Gravity.VERTICAL_GRAVITY_MASK; 347 if ((mGravity & Gravity.VERTICAL_GRAVITY_MASK) != gravity) { 348 mGravity = (mGravity & ~Gravity.VERTICAL_GRAVITY_MASK) | gravity; 349 requestLayout(); 350 } 351 } 352 353 @Override 354 public int getBaseline() { 355 return mBaselineView != null ? mBaselineView.getBaseline() : super.getBaseline(); 356 } 357 358 @Override 359 public void requestLayout() { 360 super.requestLayout(); 361 mDirtyHierarchy = true; 362 } 363 364 private void sortChildren() { 365 final int count = getChildCount(); 366 if (mSortedVerticalChildren == null || mSortedVerticalChildren.length != count) { 367 mSortedVerticalChildren = new View[count]; 368 } 369 370 if (mSortedHorizontalChildren == null || mSortedHorizontalChildren.length != count) { 371 mSortedHorizontalChildren = new View[count]; 372 } 373 374 final DependencyGraph graph = mGraph; 375 graph.clear(); 376 377 for (int i = 0; i < count; i++) { 378 graph.add(getChildAt(i)); 379 } 380 381 graph.getSortedViews(mSortedVerticalChildren, RULES_VERTICAL); 382 graph.getSortedViews(mSortedHorizontalChildren, RULES_HORIZONTAL); 383 } 384 385 @Override 386 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 387 if (mDirtyHierarchy) { 388 mDirtyHierarchy = false; 389 sortChildren(); 390 } 391 392 int myWidth = -1; 393 int myHeight = -1; 394 395 int width = 0; 396 int height = 0; 397 398 final int widthMode = MeasureSpec.getMode(widthMeasureSpec); 399 final int heightMode = MeasureSpec.getMode(heightMeasureSpec); 400 final int widthSize = MeasureSpec.getSize(widthMeasureSpec); 401 final int heightSize = MeasureSpec.getSize(heightMeasureSpec); 402 403 // Record our dimensions if they are known; 404 if (widthMode != MeasureSpec.UNSPECIFIED) { 405 myWidth = widthSize; 406 } 407 408 if (heightMode != MeasureSpec.UNSPECIFIED) { 409 myHeight = heightSize; 410 } 411 412 if (widthMode == MeasureSpec.EXACTLY) { 413 width = myWidth; 414 } 415 416 if (heightMode == MeasureSpec.EXACTLY) { 417 height = myHeight; 418 } 419 420 View ignore = null; 421 int gravity = mGravity & Gravity.RELATIVE_HORIZONTAL_GRAVITY_MASK; 422 final boolean horizontalGravity = gravity != Gravity.START && gravity != 0; 423 gravity = mGravity & Gravity.VERTICAL_GRAVITY_MASK; 424 final boolean verticalGravity = gravity != Gravity.TOP && gravity != 0; 425 426 int left = Integer.MAX_VALUE; 427 int top = Integer.MAX_VALUE; 428 int right = Integer.MIN_VALUE; 429 int bottom = Integer.MIN_VALUE; 430 431 boolean offsetHorizontalAxis = false; 432 boolean offsetVerticalAxis = false; 433 434 if ((horizontalGravity || verticalGravity) && mIgnoreGravity != View.NO_ID) { 435 ignore = findViewById(mIgnoreGravity); 436 } 437 438 final boolean isWrapContentWidth = widthMode != MeasureSpec.EXACTLY; 439 final boolean isWrapContentHeight = heightMode != MeasureSpec.EXACTLY; 440 441 // We need to know our size for doing the correct computation of children positioning in RTL 442 // mode but there is no practical way to get it instead of running the code below. 443 // So, instead of running the code twice, we just set the width to a "default display width" 444 // before the computation and then, as a last pass, we will update their real position with 445 // an offset equals to "DEFAULT_WIDTH - width". 446 final int layoutDirection = getLayoutDirection(); 447 if (isLayoutRtl() && myWidth == -1) { 448 myWidth = DEFAULT_WIDTH; 449 } 450 451 View[] views = mSortedHorizontalChildren; 452 int count = views.length; 453 454 for (int i = 0; i < count; i++) { 455 View child = views[i]; 456 if (child.getVisibility() != GONE) { 457 LayoutParams params = (LayoutParams) child.getLayoutParams(); 458 int[] rules = params.getRules(layoutDirection); 459 460 applyHorizontalSizeRules(params, myWidth, rules); 461 measureChildHorizontal(child, params, myWidth, myHeight); 462 463 if (positionChildHorizontal(child, params, myWidth, isWrapContentWidth)) { 464 offsetHorizontalAxis = true; 465 } 466 } 467 } 468 469 views = mSortedVerticalChildren; 470 count = views.length; 471 final int targetSdkVersion = getContext().getApplicationInfo().targetSdkVersion; 472 473 for (int i = 0; i < count; i++) { 474 final View child = views[i]; 475 if (child.getVisibility() != GONE) { 476 final LayoutParams params = (LayoutParams) child.getLayoutParams(); 477 478 applyVerticalSizeRules(params, myHeight, child.getBaseline()); 479 measureChild(child, params, myWidth, myHeight); 480 if (positionChildVertical(child, params, myHeight, isWrapContentHeight)) { 481 offsetVerticalAxis = true; 482 } 483 484 if (isWrapContentWidth) { 485 if (isLayoutRtl()) { 486 if (targetSdkVersion < Build.VERSION_CODES.KITKAT) { 487 width = Math.max(width, myWidth - params.mLeft); 488 } else { 489 width = Math.max(width, myWidth - params.mLeft - params.leftMargin); 490 } 491 } else { 492 if (targetSdkVersion < Build.VERSION_CODES.KITKAT) { 493 width = Math.max(width, params.mRight); 494 } else { 495 width = Math.max(width, params.mRight + params.rightMargin); 496 } 497 } 498 } 499 500 if (isWrapContentHeight) { 501 if (targetSdkVersion < Build.VERSION_CODES.KITKAT) { 502 height = Math.max(height, params.mBottom); 503 } else { 504 height = Math.max(height, params.mBottom + params.bottomMargin); 505 } 506 } 507 508 if (child != ignore || verticalGravity) { 509 left = Math.min(left, params.mLeft - params.leftMargin); 510 top = Math.min(top, params.mTop - params.topMargin); 511 } 512 513 if (child != ignore || horizontalGravity) { 514 right = Math.max(right, params.mRight + params.rightMargin); 515 bottom = Math.max(bottom, params.mBottom + params.bottomMargin); 516 } 517 } 518 } 519 520 // Use the top-start-most laid out view as the baseline. RTL offsets are 521 // applied later, so we can use the left-most edge as the starting edge. 522 View baselineView = null; 523 LayoutParams baselineParams = null; 524 for (int i = 0; i < count; i++) { 525 final View child = views[i]; 526 if (child.getVisibility() != GONE) { 527 final LayoutParams childParams = (LayoutParams) child.getLayoutParams(); 528 if (baselineView == null || baselineParams == null 529 || compareLayoutPosition(childParams, baselineParams) < 0) { 530 baselineView = child; 531 baselineParams = childParams; 532 } 533 } 534 } 535 mBaselineView = baselineView; 536 537 if (isWrapContentWidth) { 538 // Width already has left padding in it since it was calculated by looking at 539 // the right of each child view 540 width += mPaddingRight; 541 542 if (mLayoutParams != null && mLayoutParams.width >= 0) { 543 width = Math.max(width, mLayoutParams.width); 544 } 545 546 width = Math.max(width, getSuggestedMinimumWidth()); 547 width = resolveSize(width, widthMeasureSpec); 548 549 if (offsetHorizontalAxis) { 550 for (int i = 0; i < count; i++) { 551 final View child = views[i]; 552 if (child.getVisibility() != GONE) { 553 final LayoutParams params = (LayoutParams) child.getLayoutParams(); 554 final int[] rules = params.getRules(layoutDirection); 555 if (rules[CENTER_IN_PARENT] != 0 || rules[CENTER_HORIZONTAL] != 0) { 556 centerHorizontal(child, params, width); 557 } else if (rules[ALIGN_PARENT_RIGHT] != 0) { 558 final int childWidth = child.getMeasuredWidth(); 559 params.mLeft = width - mPaddingRight - childWidth; 560 params.mRight = params.mLeft + childWidth; 561 } 562 } 563 } 564 } 565 } 566 567 if (isWrapContentHeight) { 568 // Height already has top padding in it since it was calculated by looking at 569 // the bottom of each child view 570 height += mPaddingBottom; 571 572 if (mLayoutParams != null && mLayoutParams.height >= 0) { 573 height = Math.max(height, mLayoutParams.height); 574 } 575 576 height = Math.max(height, getSuggestedMinimumHeight()); 577 height = resolveSize(height, heightMeasureSpec); 578 579 if (offsetVerticalAxis) { 580 for (int i = 0; i < count; i++) { 581 final View child = views[i]; 582 if (child.getVisibility() != GONE) { 583 final LayoutParams params = (LayoutParams) child.getLayoutParams(); 584 final int[] rules = params.getRules(layoutDirection); 585 if (rules[CENTER_IN_PARENT] != 0 || rules[CENTER_VERTICAL] != 0) { 586 centerVertical(child, params, height); 587 } else if (rules[ALIGN_PARENT_BOTTOM] != 0) { 588 final int childHeight = child.getMeasuredHeight(); 589 params.mTop = height - mPaddingBottom - childHeight; 590 params.mBottom = params.mTop + childHeight; 591 } 592 } 593 } 594 } 595 } 596 597 if (horizontalGravity || verticalGravity) { 598 final Rect selfBounds = mSelfBounds; 599 selfBounds.set(mPaddingLeft, mPaddingTop, width - mPaddingRight, 600 height - mPaddingBottom); 601 602 final Rect contentBounds = mContentBounds; 603 Gravity.apply(mGravity, right - left, bottom - top, selfBounds, contentBounds, 604 layoutDirection); 605 606 final int horizontalOffset = contentBounds.left - left; 607 final int verticalOffset = contentBounds.top - top; 608 if (horizontalOffset != 0 || verticalOffset != 0) { 609 for (int i = 0; i < count; i++) { 610 final View child = views[i]; 611 if (child.getVisibility() != GONE && child != ignore) { 612 final LayoutParams params = (LayoutParams) child.getLayoutParams(); 613 if (horizontalGravity) { 614 params.mLeft += horizontalOffset; 615 params.mRight += horizontalOffset; 616 } 617 if (verticalGravity) { 618 params.mTop += verticalOffset; 619 params.mBottom += verticalOffset; 620 } 621 } 622 } 623 } 624 } 625 626 if (isLayoutRtl()) { 627 final int offsetWidth = myWidth - width; 628 for (int i = 0; i < count; i++) { 629 final View child = views[i]; 630 if (child.getVisibility() != GONE) { 631 final LayoutParams params = (LayoutParams) child.getLayoutParams(); 632 params.mLeft -= offsetWidth; 633 params.mRight -= offsetWidth; 634 } 635 } 636 } 637 638 setMeasuredDimension(width, height); 639 } 640 641 /** 642 * @return a negative number if the top of {@code p1} is above the top of 643 * {@code p2} or if they have identical top values and the left of 644 * {@code p1} is to the left of {@code p2}, or a positive number 645 * otherwise 646 */ 647 private int compareLayoutPosition(LayoutParams p1, LayoutParams p2) { 648 final int topDiff = p1.mTop - p2.mTop; 649 if (topDiff != 0) { 650 return topDiff; 651 } 652 return p1.mLeft - p2.mLeft; 653 } 654 655 /** 656 * Measure a child. The child should have left, top, right and bottom information 657 * stored in its LayoutParams. If any of these values is VALUE_NOT_SET it means 658 * that the view can extend up to the corresponding edge. 659 * 660 * @param child Child to measure 661 * @param params LayoutParams associated with child 662 * @param myWidth Width of the the RelativeLayout 663 * @param myHeight Height of the RelativeLayout 664 */ 665 private void measureChild(View child, LayoutParams params, int myWidth, int myHeight) { 666 int childWidthMeasureSpec = getChildMeasureSpec(params.mLeft, 667 params.mRight, params.width, 668 params.leftMargin, params.rightMargin, 669 mPaddingLeft, mPaddingRight, 670 myWidth); 671 int childHeightMeasureSpec = getChildMeasureSpec(params.mTop, 672 params.mBottom, params.height, 673 params.topMargin, params.bottomMargin, 674 mPaddingTop, mPaddingBottom, 675 myHeight); 676 child.measure(childWidthMeasureSpec, childHeightMeasureSpec); 677 } 678 679 private void measureChildHorizontal( 680 View child, LayoutParams params, int myWidth, int myHeight) { 681 final int childWidthMeasureSpec = getChildMeasureSpec(params.mLeft, params.mRight, 682 params.width, params.leftMargin, params.rightMargin, mPaddingLeft, mPaddingRight, 683 myWidth); 684 685 final int childHeightMeasureSpec; 686 if (myHeight < 0 && !mAllowBrokenMeasureSpecs) { 687 if (params.height >= 0) { 688 childHeightMeasureSpec = MeasureSpec.makeMeasureSpec( 689 params.height, MeasureSpec.EXACTLY); 690 } else { 691 // Negative values in a mySize/myWidth/myWidth value in 692 // RelativeLayout measurement is code for, "we got an 693 // unspecified mode in the RelativeLayout's measure spec." 694 // Carry it forward. 695 childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); 696 } 697 } else { 698 final int maxHeight; 699 if (mMeasureVerticalWithPaddingMargin) { 700 maxHeight = Math.max(0, myHeight - mPaddingTop - mPaddingBottom 701 - params.topMargin - params.bottomMargin); 702 } else { 703 maxHeight = Math.max(0, myHeight); 704 } 705 706 final int heightMode; 707 if (params.height == LayoutParams.MATCH_PARENT) { 708 heightMode = MeasureSpec.EXACTLY; 709 } else { 710 heightMode = MeasureSpec.AT_MOST; 711 } 712 childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(maxHeight, heightMode); 713 } 714 715 child.measure(childWidthMeasureSpec, childHeightMeasureSpec); 716 } 717 718 /** 719 * Get a measure spec that accounts for all of the constraints on this view. 720 * This includes size constraints imposed by the RelativeLayout as well as 721 * the View's desired dimension. 722 * 723 * @param childStart The left or top field of the child's layout params 724 * @param childEnd The right or bottom field of the child's layout params 725 * @param childSize The child's desired size (the width or height field of 726 * the child's layout params) 727 * @param startMargin The left or top margin 728 * @param endMargin The right or bottom margin 729 * @param startPadding mPaddingLeft or mPaddingTop 730 * @param endPadding mPaddingRight or mPaddingBottom 731 * @param mySize The width or height of this view (the RelativeLayout) 732 * @return MeasureSpec for the child 733 */ 734 private int getChildMeasureSpec(int childStart, int childEnd, 735 int childSize, int startMargin, int endMargin, int startPadding, 736 int endPadding, int mySize) { 737 int childSpecMode = 0; 738 int childSpecSize = 0; 739 740 // Negative values in a mySize value in RelativeLayout 741 // measurement is code for, "we got an unspecified mode in the 742 // RelativeLayout's measure spec." 743 final boolean isUnspecified = mySize < 0; 744 if (isUnspecified && !mAllowBrokenMeasureSpecs) { 745 if (childStart != VALUE_NOT_SET && childEnd != VALUE_NOT_SET) { 746 // Constraints fixed both edges, so child has an exact size. 747 childSpecSize = Math.max(0, childEnd - childStart); 748 childSpecMode = MeasureSpec.EXACTLY; 749 } else if (childSize >= 0) { 750 // The child specified an exact size. 751 childSpecSize = childSize; 752 childSpecMode = MeasureSpec.EXACTLY; 753 } else { 754 // Allow the child to be whatever size it wants. 755 childSpecSize = 0; 756 childSpecMode = MeasureSpec.UNSPECIFIED; 757 } 758 759 return MeasureSpec.makeMeasureSpec(childSpecSize, childSpecMode); 760 } 761 762 // Figure out start and end bounds. 763 int tempStart = childStart; 764 int tempEnd = childEnd; 765 766 // If the view did not express a layout constraint for an edge, use 767 // view's margins and our padding 768 if (tempStart == VALUE_NOT_SET) { 769 tempStart = startPadding + startMargin; 770 } 771 if (tempEnd == VALUE_NOT_SET) { 772 tempEnd = mySize - endPadding - endMargin; 773 } 774 775 // Figure out maximum size available to this view 776 final int maxAvailable = tempEnd - tempStart; 777 778 if (childStart != VALUE_NOT_SET && childEnd != VALUE_NOT_SET) { 779 // Constraints fixed both edges, so child must be an exact size. 780 childSpecMode = isUnspecified ? MeasureSpec.UNSPECIFIED : MeasureSpec.EXACTLY; 781 childSpecSize = Math.max(0, maxAvailable); 782 } else { 783 if (childSize >= 0) { 784 // Child wanted an exact size. Give as much as possible. 785 childSpecMode = MeasureSpec.EXACTLY; 786 787 if (maxAvailable >= 0) { 788 // We have a maximum size in this dimension. 789 childSpecSize = Math.min(maxAvailable, childSize); 790 } else { 791 // We can grow in this dimension. 792 childSpecSize = childSize; 793 } 794 } else if (childSize == LayoutParams.MATCH_PARENT) { 795 // Child wanted to be as big as possible. Give all available 796 // space. 797 childSpecMode = isUnspecified ? MeasureSpec.UNSPECIFIED : MeasureSpec.EXACTLY; 798 childSpecSize = Math.max(0, maxAvailable); 799 } else if (childSize == LayoutParams.WRAP_CONTENT) { 800 // Child wants to wrap content. Use AT_MOST to communicate 801 // available space if we know our max size. 802 if (maxAvailable >= 0) { 803 // We have a maximum size in this dimension. 804 childSpecMode = MeasureSpec.AT_MOST; 805 childSpecSize = maxAvailable; 806 } else { 807 // We can grow in this dimension. Child can be as big as it 808 // wants. 809 childSpecMode = MeasureSpec.UNSPECIFIED; 810 childSpecSize = 0; 811 } 812 } 813 } 814 815 return MeasureSpec.makeMeasureSpec(childSpecSize, childSpecMode); 816 } 817 818 private boolean positionChildHorizontal(View child, LayoutParams params, int myWidth, 819 boolean wrapContent) { 820 821 final int layoutDirection = getLayoutDirection(); 822 int[] rules = params.getRules(layoutDirection); 823 824 if (params.mLeft == VALUE_NOT_SET && params.mRight != VALUE_NOT_SET) { 825 // Right is fixed, but left varies 826 params.mLeft = params.mRight - child.getMeasuredWidth(); 827 } else if (params.mLeft != VALUE_NOT_SET && params.mRight == VALUE_NOT_SET) { 828 // Left is fixed, but right varies 829 params.mRight = params.mLeft + child.getMeasuredWidth(); 830 } else if (params.mLeft == VALUE_NOT_SET && params.mRight == VALUE_NOT_SET) { 831 // Both left and right vary 832 if (rules[CENTER_IN_PARENT] != 0 || rules[CENTER_HORIZONTAL] != 0) { 833 if (!wrapContent) { 834 centerHorizontal(child, params, myWidth); 835 } else { 836 params.mLeft = mPaddingLeft + params.leftMargin; 837 params.mRight = params.mLeft + child.getMeasuredWidth(); 838 } 839 return true; 840 } else { 841 // This is the default case. For RTL we start from the right and for LTR we start 842 // from the left. This will give LEFT/TOP for LTR and RIGHT/TOP for RTL. 843 if (isLayoutRtl()) { 844 params.mRight = myWidth - mPaddingRight- params.rightMargin; 845 params.mLeft = params.mRight - child.getMeasuredWidth(); 846 } else { 847 params.mLeft = mPaddingLeft + params.leftMargin; 848 params.mRight = params.mLeft + child.getMeasuredWidth(); 849 } 850 } 851 } 852 return rules[ALIGN_PARENT_END] != 0; 853 } 854 855 private boolean positionChildVertical(View child, LayoutParams params, int myHeight, 856 boolean wrapContent) { 857 858 int[] rules = params.getRules(); 859 860 if (params.mTop == VALUE_NOT_SET && params.mBottom != VALUE_NOT_SET) { 861 // Bottom is fixed, but top varies 862 params.mTop = params.mBottom - child.getMeasuredHeight(); 863 } else if (params.mTop != VALUE_NOT_SET && params.mBottom == VALUE_NOT_SET) { 864 // Top is fixed, but bottom varies 865 params.mBottom = params.mTop + child.getMeasuredHeight(); 866 } else if (params.mTop == VALUE_NOT_SET && params.mBottom == VALUE_NOT_SET) { 867 // Both top and bottom vary 868 if (rules[CENTER_IN_PARENT] != 0 || rules[CENTER_VERTICAL] != 0) { 869 if (!wrapContent) { 870 centerVertical(child, params, myHeight); 871 } else { 872 params.mTop = mPaddingTop + params.topMargin; 873 params.mBottom = params.mTop + child.getMeasuredHeight(); 874 } 875 return true; 876 } else { 877 params.mTop = mPaddingTop + params.topMargin; 878 params.mBottom = params.mTop + child.getMeasuredHeight(); 879 } 880 } 881 return rules[ALIGN_PARENT_BOTTOM] != 0; 882 } 883 884 private void applyHorizontalSizeRules(LayoutParams childParams, int myWidth, int[] rules) { 885 RelativeLayout.LayoutParams anchorParams; 886 887 // VALUE_NOT_SET indicates a "soft requirement" in that direction. For example: 888 // left=10, right=VALUE_NOT_SET means the view must start at 10, but can go as far as it 889 // wants to the right 890 // left=VALUE_NOT_SET, right=10 means the view must end at 10, but can go as far as it 891 // wants to the left 892 // left=10, right=20 means the left and right ends are both fixed 893 childParams.mLeft = VALUE_NOT_SET; 894 childParams.mRight = VALUE_NOT_SET; 895 896 anchorParams = getRelatedViewParams(rules, LEFT_OF); 897 if (anchorParams != null) { 898 childParams.mRight = anchorParams.mLeft - (anchorParams.leftMargin + 899 childParams.rightMargin); 900 } else if (childParams.alignWithParent && rules[LEFT_OF] != 0) { 901 if (myWidth >= 0) { 902 childParams.mRight = myWidth - mPaddingRight - childParams.rightMargin; 903 } 904 } 905 906 anchorParams = getRelatedViewParams(rules, RIGHT_OF); 907 if (anchorParams != null) { 908 childParams.mLeft = anchorParams.mRight + (anchorParams.rightMargin + 909 childParams.leftMargin); 910 } else if (childParams.alignWithParent && rules[RIGHT_OF] != 0) { 911 childParams.mLeft = mPaddingLeft + childParams.leftMargin; 912 } 913 914 anchorParams = getRelatedViewParams(rules, ALIGN_LEFT); 915 if (anchorParams != null) { 916 childParams.mLeft = anchorParams.mLeft + childParams.leftMargin; 917 } else if (childParams.alignWithParent && rules[ALIGN_LEFT] != 0) { 918 childParams.mLeft = mPaddingLeft + childParams.leftMargin; 919 } 920 921 anchorParams = getRelatedViewParams(rules, ALIGN_RIGHT); 922 if (anchorParams != null) { 923 childParams.mRight = anchorParams.mRight - childParams.rightMargin; 924 } else if (childParams.alignWithParent && rules[ALIGN_RIGHT] != 0) { 925 if (myWidth >= 0) { 926 childParams.mRight = myWidth - mPaddingRight - childParams.rightMargin; 927 } 928 } 929 930 if (0 != rules[ALIGN_PARENT_LEFT]) { 931 childParams.mLeft = mPaddingLeft + childParams.leftMargin; 932 } 933 934 if (0 != rules[ALIGN_PARENT_RIGHT]) { 935 if (myWidth >= 0) { 936 childParams.mRight = myWidth - mPaddingRight - childParams.rightMargin; 937 } 938 } 939 } 940 941 private void applyVerticalSizeRules(LayoutParams childParams, int myHeight, int myBaseline) { 942 final int[] rules = childParams.getRules(); 943 944 // Baseline alignment overrides any explicitly specified top or bottom. 945 int baselineOffset = getRelatedViewBaselineOffset(rules); 946 if (baselineOffset != -1) { 947 if (myBaseline != -1) { 948 baselineOffset -= myBaseline; 949 } 950 childParams.mTop = baselineOffset; 951 childParams.mBottom = VALUE_NOT_SET; 952 return; 953 } 954 955 RelativeLayout.LayoutParams anchorParams; 956 957 childParams.mTop = VALUE_NOT_SET; 958 childParams.mBottom = VALUE_NOT_SET; 959 960 anchorParams = getRelatedViewParams(rules, ABOVE); 961 if (anchorParams != null) { 962 childParams.mBottom = anchorParams.mTop - (anchorParams.topMargin + 963 childParams.bottomMargin); 964 } else if (childParams.alignWithParent && rules[ABOVE] != 0) { 965 if (myHeight >= 0) { 966 childParams.mBottom = myHeight - mPaddingBottom - childParams.bottomMargin; 967 } 968 } 969 970 anchorParams = getRelatedViewParams(rules, BELOW); 971 if (anchorParams != null) { 972 childParams.mTop = anchorParams.mBottom + (anchorParams.bottomMargin + 973 childParams.topMargin); 974 } else if (childParams.alignWithParent && rules[BELOW] != 0) { 975 childParams.mTop = mPaddingTop + childParams.topMargin; 976 } 977 978 anchorParams = getRelatedViewParams(rules, ALIGN_TOP); 979 if (anchorParams != null) { 980 childParams.mTop = anchorParams.mTop + childParams.topMargin; 981 } else if (childParams.alignWithParent && rules[ALIGN_TOP] != 0) { 982 childParams.mTop = mPaddingTop + childParams.topMargin; 983 } 984 985 anchorParams = getRelatedViewParams(rules, ALIGN_BOTTOM); 986 if (anchorParams != null) { 987 childParams.mBottom = anchorParams.mBottom - childParams.bottomMargin; 988 } else if (childParams.alignWithParent && rules[ALIGN_BOTTOM] != 0) { 989 if (myHeight >= 0) { 990 childParams.mBottom = myHeight - mPaddingBottom - childParams.bottomMargin; 991 } 992 } 993 994 if (0 != rules[ALIGN_PARENT_TOP]) { 995 childParams.mTop = mPaddingTop + childParams.topMargin; 996 } 997 998 if (0 != rules[ALIGN_PARENT_BOTTOM]) { 999 if (myHeight >= 0) { 1000 childParams.mBottom = myHeight - mPaddingBottom - childParams.bottomMargin; 1001 } 1002 } 1003 } 1004 1005 private View getRelatedView(int[] rules, int relation) { 1006 int id = rules[relation]; 1007 if (id != 0) { 1008 DependencyGraph.Node node = mGraph.mKeyNodes.get(id); 1009 if (node == null) return null; 1010 View v = node.view; 1011 1012 // Find the first non-GONE view up the chain 1013 while (v.getVisibility() == View.GONE) { 1014 rules = ((LayoutParams) v.getLayoutParams()).getRules(v.getLayoutDirection()); 1015 node = mGraph.mKeyNodes.get((rules[relation])); 1016 if (node == null) return null; 1017 v = node.view; 1018 } 1019 1020 return v; 1021 } 1022 1023 return null; 1024 } 1025 1026 private LayoutParams getRelatedViewParams(int[] rules, int relation) { 1027 View v = getRelatedView(rules, relation); 1028 if (v != null) { 1029 ViewGroup.LayoutParams params = v.getLayoutParams(); 1030 if (params instanceof LayoutParams) { 1031 return (LayoutParams) v.getLayoutParams(); 1032 } 1033 } 1034 return null; 1035 } 1036 1037 private int getRelatedViewBaselineOffset(int[] rules) { 1038 final View v = getRelatedView(rules, ALIGN_BASELINE); 1039 if (v != null) { 1040 final int baseline = v.getBaseline(); 1041 if (baseline != -1) { 1042 final ViewGroup.LayoutParams params = v.getLayoutParams(); 1043 if (params instanceof LayoutParams) { 1044 final LayoutParams anchorParams = (LayoutParams) v.getLayoutParams(); 1045 return anchorParams.mTop + baseline; 1046 } 1047 } 1048 } 1049 return -1; 1050 } 1051 1052 private static void centerHorizontal(View child, LayoutParams params, int myWidth) { 1053 int childWidth = child.getMeasuredWidth(); 1054 int left = (myWidth - childWidth) / 2; 1055 1056 params.mLeft = left; 1057 params.mRight = left + childWidth; 1058 } 1059 1060 private static void centerVertical(View child, LayoutParams params, int myHeight) { 1061 int childHeight = child.getMeasuredHeight(); 1062 int top = (myHeight - childHeight) / 2; 1063 1064 params.mTop = top; 1065 params.mBottom = top + childHeight; 1066 } 1067 1068 @Override 1069 protected void onLayout(boolean changed, int l, int t, int r, int b) { 1070 // The layout has actually already been performed and the positions 1071 // cached. Apply the cached values to the children. 1072 final int count = getChildCount(); 1073 1074 for (int i = 0; i < count; i++) { 1075 View child = getChildAt(i); 1076 if (child.getVisibility() != GONE) { 1077 RelativeLayout.LayoutParams st = 1078 (RelativeLayout.LayoutParams) child.getLayoutParams(); 1079 child.layout(st.mLeft, st.mTop, st.mRight, st.mBottom); 1080 } 1081 } 1082 } 1083 1084 @Override 1085 public LayoutParams generateLayoutParams(AttributeSet attrs) { 1086 return new RelativeLayout.LayoutParams(getContext(), attrs); 1087 } 1088 1089 /** 1090 * Returns a set of layout parameters with a width of 1091 * {@link android.view.ViewGroup.LayoutParams#WRAP_CONTENT}, 1092 * a height of {@link android.view.ViewGroup.LayoutParams#WRAP_CONTENT} and no spanning. 1093 */ 1094 @Override 1095 protected ViewGroup.LayoutParams generateDefaultLayoutParams() { 1096 return new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT); 1097 } 1098 1099 // Override to allow type-checking of LayoutParams. 1100 @Override 1101 protected boolean checkLayoutParams(ViewGroup.LayoutParams p) { 1102 return p instanceof RelativeLayout.LayoutParams; 1103 } 1104 1105 @Override 1106 protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams lp) { 1107 if (sPreserveMarginParamsInLayoutParamConversion) { 1108 if (lp instanceof LayoutParams) { 1109 return new LayoutParams((LayoutParams) lp); 1110 } else if (lp instanceof MarginLayoutParams) { 1111 return new LayoutParams((MarginLayoutParams) lp); 1112 } 1113 } 1114 return new LayoutParams(lp); 1115 } 1116 1117 /** @hide */ 1118 @Override 1119 public boolean dispatchPopulateAccessibilityEventInternal(AccessibilityEvent event) { 1120 if (mTopToBottomLeftToRightSet == null) { 1121 mTopToBottomLeftToRightSet = new TreeSet<View>(new TopToBottomLeftToRightComparator()); 1122 } 1123 1124 // sort children top-to-bottom and left-to-right 1125 for (int i = 0, count = getChildCount(); i < count; i++) { 1126 mTopToBottomLeftToRightSet.add(getChildAt(i)); 1127 } 1128 1129 for (View view : mTopToBottomLeftToRightSet) { 1130 if (view.getVisibility() == View.VISIBLE 1131 && view.dispatchPopulateAccessibilityEvent(event)) { 1132 mTopToBottomLeftToRightSet.clear(); 1133 return true; 1134 } 1135 } 1136 1137 mTopToBottomLeftToRightSet.clear(); 1138 return false; 1139 } 1140 1141 @Override 1142 public CharSequence getAccessibilityClassName() { 1143 return RelativeLayout.class.getName(); 1144 } 1145 1146 /** 1147 * Compares two views in left-to-right and top-to-bottom fashion. 1148 */ 1149 private class TopToBottomLeftToRightComparator implements Comparator<View> { 1150 public int compare(View first, View second) { 1151 // top - bottom 1152 int topDifference = first.getTop() - second.getTop(); 1153 if (topDifference != 0) { 1154 return topDifference; 1155 } 1156 // left - right 1157 int leftDifference = first.getLeft() - second.getLeft(); 1158 if (leftDifference != 0) { 1159 return leftDifference; 1160 } 1161 // break tie by height 1162 int heightDiference = first.getHeight() - second.getHeight(); 1163 if (heightDiference != 0) { 1164 return heightDiference; 1165 } 1166 // break tie by width 1167 int widthDiference = first.getWidth() - second.getWidth(); 1168 if (widthDiference != 0) { 1169 return widthDiference; 1170 } 1171 return 0; 1172 } 1173 } 1174 1175 /** 1176 * Per-child layout information associated with RelativeLayout. 1177 * 1178 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignWithParentIfMissing 1179 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_toLeftOf 1180 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_toRightOf 1181 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_above 1182 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_below 1183 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignBaseline 1184 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignLeft 1185 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignTop 1186 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignRight 1187 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignBottom 1188 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignParentLeft 1189 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignParentTop 1190 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignParentRight 1191 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignParentBottom 1192 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_centerInParent 1193 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_centerHorizontal 1194 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_centerVertical 1195 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_toStartOf 1196 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_toEndOf 1197 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignStart 1198 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignEnd 1199 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignParentStart 1200 * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignParentEnd 1201 */ 1202 public static class LayoutParams extends ViewGroup.MarginLayoutParams { 1203 @ViewDebug.ExportedProperty(category = "layout", resolveId = true, indexMapping = { 1204 @ViewDebug.IntToString(from = ABOVE, to = "above"), 1205 @ViewDebug.IntToString(from = ALIGN_BASELINE, to = "alignBaseline"), 1206 @ViewDebug.IntToString(from = ALIGN_BOTTOM, to = "alignBottom"), 1207 @ViewDebug.IntToString(from = ALIGN_LEFT, to = "alignLeft"), 1208 @ViewDebug.IntToString(from = ALIGN_PARENT_BOTTOM, to = "alignParentBottom"), 1209 @ViewDebug.IntToString(from = ALIGN_PARENT_LEFT, to = "alignParentLeft"), 1210 @ViewDebug.IntToString(from = ALIGN_PARENT_RIGHT, to = "alignParentRight"), 1211 @ViewDebug.IntToString(from = ALIGN_PARENT_TOP, to = "alignParentTop"), 1212 @ViewDebug.IntToString(from = ALIGN_RIGHT, to = "alignRight"), 1213 @ViewDebug.IntToString(from = ALIGN_TOP, to = "alignTop"), 1214 @ViewDebug.IntToString(from = BELOW, to = "below"), 1215 @ViewDebug.IntToString(from = CENTER_HORIZONTAL, to = "centerHorizontal"), 1216 @ViewDebug.IntToString(from = CENTER_IN_PARENT, to = "center"), 1217 @ViewDebug.IntToString(from = CENTER_VERTICAL, to = "centerVertical"), 1218 @ViewDebug.IntToString(from = LEFT_OF, to = "leftOf"), 1219 @ViewDebug.IntToString(from = RIGHT_OF, to = "rightOf"), 1220 @ViewDebug.IntToString(from = ALIGN_START, to = "alignStart"), 1221 @ViewDebug.IntToString(from = ALIGN_END, to = "alignEnd"), 1222 @ViewDebug.IntToString(from = ALIGN_PARENT_START, to = "alignParentStart"), 1223 @ViewDebug.IntToString(from = ALIGN_PARENT_END, to = "alignParentEnd"), 1224 @ViewDebug.IntToString(from = START_OF, to = "startOf"), 1225 @ViewDebug.IntToString(from = END_OF, to = "endOf") 1226 }, mapping = { 1227 @ViewDebug.IntToString(from = TRUE, to = "true"), 1228 @ViewDebug.IntToString(from = 0, to = "false/NO_ID") 1229 }) 1230 1231 private int[] mRules = new int[VERB_COUNT]; 1232 private int[] mInitialRules = new int[VERB_COUNT]; 1233 1234 private int mLeft, mTop, mRight, mBottom; 1235 1236 /** 1237 * Whether this view had any relative rules modified following the most 1238 * recent resolution of layout direction. 1239 */ 1240 private boolean mNeedsLayoutResolution; 1241 1242 private boolean mRulesChanged = false; 1243 private boolean mIsRtlCompatibilityMode = false; 1244 1245 /** 1246 * When true, uses the parent as the anchor if the anchor doesn't exist or if 1247 * the anchor's visibility is GONE. 1248 */ 1249 @ViewDebug.ExportedProperty(category = "layout") 1250 public boolean alignWithParent; 1251 1252 public LayoutParams(Context c, AttributeSet attrs) { 1253 super(c, attrs); 1254 1255 TypedArray a = c.obtainStyledAttributes(attrs, 1256 com.android.internal.R.styleable.RelativeLayout_Layout); 1257 1258 final int targetSdkVersion = c.getApplicationInfo().targetSdkVersion; 1259 mIsRtlCompatibilityMode = (targetSdkVersion < JELLY_BEAN_MR1 || 1260 !c.getApplicationInfo().hasRtlSupport()); 1261 1262 final int[] rules = mRules; 1263 //noinspection MismatchedReadAndWriteOfArray 1264 final int[] initialRules = mInitialRules; 1265 1266 final int N = a.getIndexCount(); 1267 for (int i = 0; i < N; i++) { 1268 int attr = a.getIndex(i); 1269 switch (attr) { 1270 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignWithParentIfMissing: 1271 alignWithParent = a.getBoolean(attr, false); 1272 break; 1273 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_toLeftOf: 1274 rules[LEFT_OF] = a.getResourceId(attr, 0); 1275 break; 1276 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_toRightOf: 1277 rules[RIGHT_OF] = a.getResourceId(attr, 0); 1278 break; 1279 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_above: 1280 rules[ABOVE] = a.getResourceId(attr, 0); 1281 break; 1282 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_below: 1283 rules[BELOW] = a.getResourceId(attr, 0); 1284 break; 1285 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignBaseline: 1286 rules[ALIGN_BASELINE] = a.getResourceId(attr, 0); 1287 break; 1288 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignLeft: 1289 rules[ALIGN_LEFT] = a.getResourceId(attr, 0); 1290 break; 1291 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignTop: 1292 rules[ALIGN_TOP] = a.getResourceId(attr, 0); 1293 break; 1294 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignRight: 1295 rules[ALIGN_RIGHT] = a.getResourceId(attr, 0); 1296 break; 1297 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignBottom: 1298 rules[ALIGN_BOTTOM] = a.getResourceId(attr, 0); 1299 break; 1300 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignParentLeft: 1301 rules[ALIGN_PARENT_LEFT] = a.getBoolean(attr, false) ? TRUE : 0; 1302 break; 1303 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignParentTop: 1304 rules[ALIGN_PARENT_TOP] = a.getBoolean(attr, false) ? TRUE : 0; 1305 break; 1306 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignParentRight: 1307 rules[ALIGN_PARENT_RIGHT] = a.getBoolean(attr, false) ? TRUE : 0; 1308 break; 1309 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignParentBottom: 1310 rules[ALIGN_PARENT_BOTTOM] = a.getBoolean(attr, false) ? TRUE : 0; 1311 break; 1312 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_centerInParent: 1313 rules[CENTER_IN_PARENT] = a.getBoolean(attr, false) ? TRUE : 0; 1314 break; 1315 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_centerHorizontal: 1316 rules[CENTER_HORIZONTAL] = a.getBoolean(attr, false) ? TRUE : 0; 1317 break; 1318 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_centerVertical: 1319 rules[CENTER_VERTICAL] = a.getBoolean(attr, false) ? TRUE : 0; 1320 break; 1321 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_toStartOf: 1322 rules[START_OF] = a.getResourceId(attr, 0); 1323 break; 1324 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_toEndOf: 1325 rules[END_OF] = a.getResourceId(attr, 0); 1326 break; 1327 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignStart: 1328 rules[ALIGN_START] = a.getResourceId(attr, 0); 1329 break; 1330 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignEnd: 1331 rules[ALIGN_END] = a.getResourceId(attr, 0); 1332 break; 1333 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignParentStart: 1334 rules[ALIGN_PARENT_START] = a.getBoolean(attr, false) ? TRUE : 0; 1335 break; 1336 case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignParentEnd: 1337 rules[ALIGN_PARENT_END] = a.getBoolean(attr, false) ? TRUE : 0; 1338 break; 1339 } 1340 } 1341 mRulesChanged = true; 1342 System.arraycopy(rules, LEFT_OF, initialRules, LEFT_OF, VERB_COUNT); 1343 1344 a.recycle(); 1345 } 1346 1347 public LayoutParams(int w, int h) { 1348 super(w, h); 1349 } 1350 1351 /** 1352 * {@inheritDoc} 1353 */ 1354 public LayoutParams(ViewGroup.LayoutParams source) { 1355 super(source); 1356 } 1357 1358 /** 1359 * {@inheritDoc} 1360 */ 1361 public LayoutParams(ViewGroup.MarginLayoutParams source) { 1362 super(source); 1363 } 1364 1365 /** 1366 * Copy constructor. Clones the width, height, margin values, and rules 1367 * of the source. 1368 * 1369 * @param source The layout params to copy from. 1370 */ 1371 public LayoutParams(LayoutParams source) { 1372 super(source); 1373 1374 this.mIsRtlCompatibilityMode = source.mIsRtlCompatibilityMode; 1375 this.mRulesChanged = source.mRulesChanged; 1376 this.alignWithParent = source.alignWithParent; 1377 1378 System.arraycopy(source.mRules, LEFT_OF, this.mRules, LEFT_OF, VERB_COUNT); 1379 System.arraycopy( 1380 source.mInitialRules, LEFT_OF, this.mInitialRules, LEFT_OF, VERB_COUNT); 1381 } 1382 1383 @Override 1384 public String debug(String output) { 1385 return output + "ViewGroup.LayoutParams={ width=" + sizeToString(width) + 1386 ", height=" + sizeToString(height) + " }"; 1387 } 1388 1389 /** 1390 * Adds a layout rule to be interpreted by the RelativeLayout. 1391 * <p> 1392 * This method should only be used for verbs that don't refer to a 1393 * sibling (ex. {@link #ALIGN_RIGHT}) or take a boolean 1394 * value ({@link #TRUE} for true or 0 for false). To 1395 * specify a verb that takes a subject, use {@link #addRule(int, int)}. 1396 * <p> 1397 * If the rule is relative to the layout direction (ex. 1398 * {@link #ALIGN_PARENT_START}), then the layout direction must be 1399 * resolved using {@link #resolveLayoutDirection(int)} before calling 1400 * {@link #getRule(int)} an absolute rule (ex. 1401 * {@link #ALIGN_PARENT_LEFT}. 1402 * 1403 * @param verb a layout verb, such as {@link #ALIGN_PARENT_LEFT} 1404 * @see #addRule(int, int) 1405 * @see #removeRule(int) 1406 * @see #getRule(int) 1407 */ 1408 public void addRule(int verb) { 1409 addRule(verb, TRUE); 1410 } 1411 1412 /** 1413 * Adds a layout rule to be interpreted by the RelativeLayout. 1414 * <p> 1415 * Use this for verbs that refer to a sibling (ex. 1416 * {@link #ALIGN_RIGHT}) or take a boolean value (ex. 1417 * {@link #CENTER_IN_PARENT}). 1418 * <p> 1419 * If the rule is relative to the layout direction (ex. 1420 * {@link #START_OF}), then the layout direction must be resolved using 1421 * {@link #resolveLayoutDirection(int)} before calling 1422 * {@link #getRule(int)} with an absolute rule (ex. {@link #LEFT_OF}. 1423 * 1424 * @param verb a layout verb, such as {@link #ALIGN_RIGHT} 1425 * @param subject the ID of another view to use as an anchor, or a 1426 * boolean value (represented as {@link #TRUE} for true 1427 * or 0 for false) 1428 * @see #addRule(int) 1429 * @see #removeRule(int) 1430 * @see #getRule(int) 1431 */ 1432 public void addRule(int verb, int subject) { 1433 // If we're removing a relative rule, we'll need to force layout 1434 // resolution the next time it's requested. 1435 if (!mNeedsLayoutResolution && isRelativeRule(verb) 1436 && mInitialRules[verb] != 0 && subject == 0) { 1437 mNeedsLayoutResolution = true; 1438 } 1439 1440 mRules[verb] = subject; 1441 mInitialRules[verb] = subject; 1442 mRulesChanged = true; 1443 } 1444 1445 /** 1446 * Removes a layout rule to be interpreted by the RelativeLayout. 1447 * <p> 1448 * If the rule is relative to the layout direction (ex. 1449 * {@link #START_OF}, {@link #ALIGN_PARENT_START}, etc.) then the 1450 * layout direction must be resolved using 1451 * {@link #resolveLayoutDirection(int)} before before calling 1452 * {@link #getRule(int)} with an absolute rule (ex. {@link #LEFT_OF}. 1453 * 1454 * @param verb One of the verbs defined by 1455 * {@link android.widget.RelativeLayout RelativeLayout}, such as 1456 * ALIGN_WITH_PARENT_LEFT. 1457 * @see #addRule(int) 1458 * @see #addRule(int, int) 1459 * @see #getRule(int) 1460 */ 1461 public void removeRule(int verb) { 1462 addRule(verb, 0); 1463 } 1464 1465 /** 1466 * Returns the layout rule associated with a specific verb. 1467 * 1468 * @param verb one of the verbs defined by {@link RelativeLayout}, such 1469 * as ALIGN_WITH_PARENT_LEFT 1470 * @return the id of another view to use as an anchor, a boolean value 1471 * (represented as {@link RelativeLayout#TRUE} for true 1472 * or 0 for false), or -1 for verbs that don't refer to another 1473 * sibling (for example, ALIGN_WITH_PARENT_BOTTOM) 1474 * @see #addRule(int) 1475 * @see #addRule(int, int) 1476 */ 1477 public int getRule(int verb) { 1478 return mRules[verb]; 1479 } 1480 1481 private boolean hasRelativeRules() { 1482 return (mInitialRules[START_OF] != 0 || mInitialRules[END_OF] != 0 || 1483 mInitialRules[ALIGN_START] != 0 || mInitialRules[ALIGN_END] != 0 || 1484 mInitialRules[ALIGN_PARENT_START] != 0 || mInitialRules[ALIGN_PARENT_END] != 0); 1485 } 1486 1487 private boolean isRelativeRule(int rule) { 1488 return rule == START_OF || rule == END_OF 1489 || rule == ALIGN_START || rule == ALIGN_END 1490 || rule == ALIGN_PARENT_START || rule == ALIGN_PARENT_END; 1491 } 1492 1493 // The way we are resolving rules depends on the layout direction and if we are pre JB MR1 1494 // or not. 1495 // 1496 // If we are pre JB MR1 (said as "RTL compatibility mode"), "left"/"right" rules are having 1497 // predominance over any "start/end" rules that could have been defined. A special case: 1498 // if no "left"/"right" rule has been defined and "start"/"end" rules are defined then we 1499 // resolve those "start"/"end" rules to "left"/"right" respectively. 1500 // 1501 // If we are JB MR1+, then "start"/"end" rules are having predominance over "left"/"right" 1502 // rules. If no "start"/"end" rule is defined then we use "left"/"right" rules. 1503 // 1504 // In all cases, the result of the resolution should clear the "start"/"end" rules to leave 1505 // only the "left"/"right" rules at the end. 1506 private void resolveRules(int layoutDirection) { 1507 final boolean isLayoutRtl = (layoutDirection == View.LAYOUT_DIRECTION_RTL); 1508 1509 // Reset to initial state 1510 System.arraycopy(mInitialRules, LEFT_OF, mRules, LEFT_OF, VERB_COUNT); 1511 1512 // Apply rules depending on direction and if we are in RTL compatibility mode 1513 if (mIsRtlCompatibilityMode) { 1514 if (mRules[ALIGN_START] != 0) { 1515 if (mRules[ALIGN_LEFT] == 0) { 1516 // "left" rule is not defined but "start" rule is: use the "start" rule as 1517 // the "left" rule 1518 mRules[ALIGN_LEFT] = mRules[ALIGN_START]; 1519 } 1520 mRules[ALIGN_START] = 0; 1521 } 1522 1523 if (mRules[ALIGN_END] != 0) { 1524 if (mRules[ALIGN_RIGHT] == 0) { 1525 // "right" rule is not defined but "end" rule is: use the "end" rule as the 1526 // "right" rule 1527 mRules[ALIGN_RIGHT] = mRules[ALIGN_END]; 1528 } 1529 mRules[ALIGN_END] = 0; 1530 } 1531 1532 if (mRules[START_OF] != 0) { 1533 if (mRules[LEFT_OF] == 0) { 1534 // "left" rule is not defined but "start" rule is: use the "start" rule as 1535 // the "left" rule 1536 mRules[LEFT_OF] = mRules[START_OF]; 1537 } 1538 mRules[START_OF] = 0; 1539 } 1540 1541 if (mRules[END_OF] != 0) { 1542 if (mRules[RIGHT_OF] == 0) { 1543 // "right" rule is not defined but "end" rule is: use the "end" rule as the 1544 // "right" rule 1545 mRules[RIGHT_OF] = mRules[END_OF]; 1546 } 1547 mRules[END_OF] = 0; 1548 } 1549 1550 if (mRules[ALIGN_PARENT_START] != 0) { 1551 if (mRules[ALIGN_PARENT_LEFT] == 0) { 1552 // "left" rule is not defined but "start" rule is: use the "start" rule as 1553 // the "left" rule 1554 mRules[ALIGN_PARENT_LEFT] = mRules[ALIGN_PARENT_START]; 1555 } 1556 mRules[ALIGN_PARENT_START] = 0; 1557 } 1558 1559 if (mRules[ALIGN_PARENT_END] != 0) { 1560 if (mRules[ALIGN_PARENT_RIGHT] == 0) { 1561 // "right" rule is not defined but "end" rule is: use the "end" rule as the 1562 // "right" rule 1563 mRules[ALIGN_PARENT_RIGHT] = mRules[ALIGN_PARENT_END]; 1564 } 1565 mRules[ALIGN_PARENT_END] = 0; 1566 } 1567 } else { 1568 // JB MR1+ case 1569 if ((mRules[ALIGN_START] != 0 || mRules[ALIGN_END] != 0) && 1570 (mRules[ALIGN_LEFT] != 0 || mRules[ALIGN_RIGHT] != 0)) { 1571 // "start"/"end" rules take precedence over "left"/"right" rules 1572 mRules[ALIGN_LEFT] = 0; 1573 mRules[ALIGN_RIGHT] = 0; 1574 } 1575 if (mRules[ALIGN_START] != 0) { 1576 // "start" rule resolved to "left" or "right" depending on the direction 1577 mRules[isLayoutRtl ? ALIGN_RIGHT : ALIGN_LEFT] = mRules[ALIGN_START]; 1578 mRules[ALIGN_START] = 0; 1579 } 1580 if (mRules[ALIGN_END] != 0) { 1581 // "end" rule resolved to "left" or "right" depending on the direction 1582 mRules[isLayoutRtl ? ALIGN_LEFT : ALIGN_RIGHT] = mRules[ALIGN_END]; 1583 mRules[ALIGN_END] = 0; 1584 } 1585 1586 if ((mRules[START_OF] != 0 || mRules[END_OF] != 0) && 1587 (mRules[LEFT_OF] != 0 || mRules[RIGHT_OF] != 0)) { 1588 // "start"/"end" rules take precedence over "left"/"right" rules 1589 mRules[LEFT_OF] = 0; 1590 mRules[RIGHT_OF] = 0; 1591 } 1592 if (mRules[START_OF] != 0) { 1593 // "start" rule resolved to "left" or "right" depending on the direction 1594 mRules[isLayoutRtl ? RIGHT_OF : LEFT_OF] = mRules[START_OF]; 1595 mRules[START_OF] = 0; 1596 } 1597 if (mRules[END_OF] != 0) { 1598 // "end" rule resolved to "left" or "right" depending on the direction 1599 mRules[isLayoutRtl ? LEFT_OF : RIGHT_OF] = mRules[END_OF]; 1600 mRules[END_OF] = 0; 1601 } 1602 1603 if ((mRules[ALIGN_PARENT_START] != 0 || mRules[ALIGN_PARENT_END] != 0) && 1604 (mRules[ALIGN_PARENT_LEFT] != 0 || mRules[ALIGN_PARENT_RIGHT] != 0)) { 1605 // "start"/"end" rules take precedence over "left"/"right" rules 1606 mRules[ALIGN_PARENT_LEFT] = 0; 1607 mRules[ALIGN_PARENT_RIGHT] = 0; 1608 } 1609 if (mRules[ALIGN_PARENT_START] != 0) { 1610 // "start" rule resolved to "left" or "right" depending on the direction 1611 mRules[isLayoutRtl ? ALIGN_PARENT_RIGHT : ALIGN_PARENT_LEFT] = mRules[ALIGN_PARENT_START]; 1612 mRules[ALIGN_PARENT_START] = 0; 1613 } 1614 if (mRules[ALIGN_PARENT_END] != 0) { 1615 // "end" rule resolved to "left" or "right" depending on the direction 1616 mRules[isLayoutRtl ? ALIGN_PARENT_LEFT : ALIGN_PARENT_RIGHT] = mRules[ALIGN_PARENT_END]; 1617 mRules[ALIGN_PARENT_END] = 0; 1618 } 1619 } 1620 1621 mRulesChanged = false; 1622 mNeedsLayoutResolution = false; 1623 } 1624 1625 /** 1626 * Retrieves a complete list of all supported rules, where the index is the rule 1627 * verb, and the element value is the value specified, or "false" if it was never 1628 * set. If there are relative rules defined (*_START / *_END), they will be resolved 1629 * depending on the layout direction. 1630 * 1631 * @param layoutDirection the direction of the layout. 1632 * Should be either {@link View#LAYOUT_DIRECTION_LTR} 1633 * or {@link View#LAYOUT_DIRECTION_RTL} 1634 * @return the supported rules 1635 * @see #addRule(int, int) 1636 * 1637 * @hide 1638 */ 1639 public int[] getRules(int layoutDirection) { 1640 resolveLayoutDirection(layoutDirection); 1641 return mRules; 1642 } 1643 1644 /** 1645 * Retrieves a complete list of all supported rules, where the index is the rule 1646 * verb, and the element value is the value specified, or "false" if it was never 1647 * set. There will be no resolution of relative rules done. 1648 * 1649 * @return the supported rules 1650 * @see #addRule(int, int) 1651 */ 1652 public int[] getRules() { 1653 return mRules; 1654 } 1655 1656 /** 1657 * This will be called by {@link android.view.View#requestLayout()} to 1658 * resolve layout parameters that are relative to the layout direction. 1659 * <p> 1660 * After this method is called, any rules using layout-relative verbs 1661 * (ex. {@link #START_OF}) previously added via {@link #addRule(int)} 1662 * may only be accessed via their resolved absolute verbs (ex. 1663 * {@link #LEFT_OF}). 1664 */ 1665 @Override 1666 public void resolveLayoutDirection(int layoutDirection) { 1667 if (shouldResolveLayoutDirection(layoutDirection)) { 1668 resolveRules(layoutDirection); 1669 } 1670 1671 // This will set the layout direction. 1672 super.resolveLayoutDirection(layoutDirection); 1673 } 1674 1675 private boolean shouldResolveLayoutDirection(int layoutDirection) { 1676 return (mNeedsLayoutResolution || hasRelativeRules()) 1677 && (mRulesChanged || layoutDirection != getLayoutDirection()); 1678 } 1679 1680 /** @hide */ 1681 @Override 1682 protected void encodeProperties(@NonNull ViewHierarchyEncoder encoder) { 1683 super.encodeProperties(encoder); 1684 encoder.addProperty("layout:alignWithParent", alignWithParent); 1685 } 1686 } 1687 1688 private static class DependencyGraph { 1689 /** 1690 * List of all views in the graph. 1691 */ 1692 private ArrayList<Node> mNodes = new ArrayList<Node>(); 1693 1694 /** 1695 * List of nodes in the graph. Each node is identified by its 1696 * view id (see View#getId()). 1697 */ 1698 private SparseArray<Node> mKeyNodes = new SparseArray<Node>(); 1699 1700 /** 1701 * Temporary data structure used to build the list of roots 1702 * for this graph. 1703 */ 1704 private ArrayDeque<Node> mRoots = new ArrayDeque<Node>(); 1705 1706 /** 1707 * Clears the graph. 1708 */ 1709 void clear() { 1710 final ArrayList<Node> nodes = mNodes; 1711 final int count = nodes.size(); 1712 1713 for (int i = 0; i < count; i++) { 1714 nodes.get(i).release(); 1715 } 1716 nodes.clear(); 1717 1718 mKeyNodes.clear(); 1719 mRoots.clear(); 1720 } 1721 1722 /** 1723 * Adds a view to the graph. 1724 * 1725 * @param view The view to be added as a node to the graph. 1726 */ 1727 void add(View view) { 1728 final int id = view.getId(); 1729 final Node node = Node.acquire(view); 1730 1731 if (id != View.NO_ID) { 1732 mKeyNodes.put(id, node); 1733 } 1734 1735 mNodes.add(node); 1736 } 1737 1738 /** 1739 * Builds a sorted list of views. The sorting order depends on the dependencies 1740 * between the view. For instance, if view C needs view A to be processed first 1741 * and view A needs view B to be processed first, the dependency graph 1742 * is: B -> A -> C. The sorted array will contain views B, A and C in this order. 1743 * 1744 * @param sorted The sorted list of views. The length of this array must 1745 * be equal to getChildCount(). 1746 * @param rules The list of rules to take into account. 1747 */ 1748 void getSortedViews(View[] sorted, int... rules) { 1749 final ArrayDeque<Node> roots = findRoots(rules); 1750 int index = 0; 1751 1752 Node node; 1753 while ((node = roots.pollLast()) != null) { 1754 final View view = node.view; 1755 final int key = view.getId(); 1756 1757 sorted[index++] = view; 1758 1759 final ArrayMap<Node, DependencyGraph> dependents = node.dependents; 1760 final int count = dependents.size(); 1761 for (int i = 0; i < count; i++) { 1762 final Node dependent = dependents.keyAt(i); 1763 final SparseArray<Node> dependencies = dependent.dependencies; 1764 1765 dependencies.remove(key); 1766 if (dependencies.size() == 0) { 1767 roots.add(dependent); 1768 } 1769 } 1770 } 1771 1772 if (index < sorted.length) { 1773 throw new IllegalStateException("Circular dependencies cannot exist" 1774 + " in RelativeLayout"); 1775 } 1776 } 1777 1778 /** 1779 * Finds the roots of the graph. A root is a node with no dependency and 1780 * with [0..n] dependents. 1781 * 1782 * @param rulesFilter The list of rules to consider when building the 1783 * dependencies 1784 * 1785 * @return A list of node, each being a root of the graph 1786 */ 1787 private ArrayDeque<Node> findRoots(int[] rulesFilter) { 1788 final SparseArray<Node> keyNodes = mKeyNodes; 1789 final ArrayList<Node> nodes = mNodes; 1790 final int count = nodes.size(); 1791 1792 // Find roots can be invoked several times, so make sure to clear 1793 // all dependents and dependencies before running the algorithm 1794 for (int i = 0; i < count; i++) { 1795 final Node node = nodes.get(i); 1796 node.dependents.clear(); 1797 node.dependencies.clear(); 1798 } 1799 1800 // Builds up the dependents and dependencies for each node of the graph 1801 for (int i = 0; i < count; i++) { 1802 final Node node = nodes.get(i); 1803 1804 final LayoutParams layoutParams = (LayoutParams) node.view.getLayoutParams(); 1805 final int[] rules = layoutParams.mRules; 1806 final int rulesCount = rulesFilter.length; 1807 1808 // Look only the the rules passed in parameter, this way we build only the 1809 // dependencies for a specific set of rules 1810 for (int j = 0; j < rulesCount; j++) { 1811 final int rule = rules[rulesFilter[j]]; 1812 if (rule > 0) { 1813 // The node this node depends on 1814 final Node dependency = keyNodes.get(rule); 1815 // Skip unknowns and self dependencies 1816 if (dependency == null || dependency == node) { 1817 continue; 1818 } 1819 // Add the current node as a dependent 1820 dependency.dependents.put(node, this); 1821 // Add a dependency to the current node 1822 node.dependencies.put(rule, dependency); 1823 } 1824 } 1825 } 1826 1827 final ArrayDeque<Node> roots = mRoots; 1828 roots.clear(); 1829 1830 // Finds all the roots in the graph: all nodes with no dependencies 1831 for (int i = 0; i < count; i++) { 1832 final Node node = nodes.get(i); 1833 if (node.dependencies.size() == 0) roots.addLast(node); 1834 } 1835 1836 return roots; 1837 } 1838 1839 /** 1840 * A node in the dependency graph. A node is a view, its list of dependencies 1841 * and its list of dependents. 1842 * 1843 * A node with no dependent is considered a root of the graph. 1844 */ 1845 static class Node { 1846 /** 1847 * The view representing this node in the layout. 1848 */ 1849 View view; 1850 1851 /** 1852 * The list of dependents for this node; a dependent is a node 1853 * that needs this node to be processed first. 1854 */ 1855 final ArrayMap<Node, DependencyGraph> dependents = 1856 new ArrayMap<Node, DependencyGraph>(); 1857 1858 /** 1859 * The list of dependencies for this node. 1860 */ 1861 final SparseArray<Node> dependencies = new SparseArray<Node>(); 1862 1863 /* 1864 * START POOL IMPLEMENTATION 1865 */ 1866 // The pool is static, so all nodes instances are shared across 1867 // activities, that's why we give it a rather high limit 1868 private static final int POOL_LIMIT = 100; 1869 private static final SynchronizedPool<Node> sPool = 1870 new SynchronizedPool<Node>(POOL_LIMIT); 1871 1872 static Node acquire(View view) { 1873 Node node = sPool.acquire(); 1874 if (node == null) { 1875 node = new Node(); 1876 } 1877 node.view = view; 1878 return node; 1879 } 1880 1881 void release() { 1882 view = null; 1883 dependents.clear(); 1884 dependencies.clear(); 1885 1886 sPool.release(this); 1887 } 1888 /* 1889 * END POOL IMPLEMENTATION 1890 */ 1891 } 1892 } 1893 } 1894