1 /* 2 * Copyright (C) 2007 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.content.Context; 20 import android.content.res.TypedArray; 21 import android.graphics.drawable.shapes.RectShape; 22 import android.graphics.drawable.shapes.Shape; 23 import android.util.AttributeSet; 24 import android.view.accessibility.AccessibilityEvent; 25 import android.view.accessibility.AccessibilityNodeInfo; 26 27 import com.android.internal.R; 28 29 /** 30 * A RatingBar is an extension of SeekBar and ProgressBar that shows a rating in 31 * stars. The user can touch/drag or use arrow keys to set the rating when using 32 * the default size RatingBar. The smaller RatingBar style ( 33 * {@link android.R.attr#ratingBarStyleSmall}) and the larger indicator-only 34 * style ({@link android.R.attr#ratingBarStyleIndicator}) do not support user 35 * interaction and should only be used as indicators. 36 * <p> 37 * When using a RatingBar that supports user interaction, placing widgets to the 38 * left or right of the RatingBar is discouraged. 39 * <p> 40 * The number of stars set (via {@link #setNumStars(int)} or in an XML layout) 41 * will be shown when the layout width is set to wrap content (if another layout 42 * width is set, the results may be unpredictable). 43 * <p> 44 * The secondary progress should not be modified by the client as it is used 45 * internally as the background for a fractionally filled star. 46 * 47 * @attr ref android.R.styleable#RatingBar_numStars 48 * @attr ref android.R.styleable#RatingBar_rating 49 * @attr ref android.R.styleable#RatingBar_stepSize 50 * @attr ref android.R.styleable#RatingBar_isIndicator 51 */ 52 public class RatingBar extends AbsSeekBar { 53 54 /** 55 * A callback that notifies clients when the rating has been changed. This 56 * includes changes that were initiated by the user through a touch gesture 57 * or arrow key/trackball as well as changes that were initiated 58 * programmatically. 59 */ 60 public interface OnRatingBarChangeListener { 61 62 /** 63 * Notification that the rating has changed. Clients can use the 64 * fromUser parameter to distinguish user-initiated changes from those 65 * that occurred programmatically. This will not be called continuously 66 * while the user is dragging, only when the user finalizes a rating by 67 * lifting the touch. 68 * 69 * @param ratingBar The RatingBar whose rating has changed. 70 * @param rating The current rating. This will be in the range 71 * 0..numStars. 72 * @param fromUser True if the rating change was initiated by a user's 73 * touch gesture or arrow key/horizontal trackbell movement. 74 */ 75 void onRatingChanged(RatingBar ratingBar, float rating, boolean fromUser); 76 77 } 78 79 private int mNumStars = 5; 80 81 private int mProgressOnStartTracking; 82 83 private OnRatingBarChangeListener mOnRatingBarChangeListener; 84 85 public RatingBar(Context context, AttributeSet attrs, int defStyle) { 86 super(context, attrs, defStyle); 87 88 TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.RatingBar, 89 defStyle, 0); 90 final int numStars = a.getInt(R.styleable.RatingBar_numStars, mNumStars); 91 setIsIndicator(a.getBoolean(R.styleable.RatingBar_isIndicator, !mIsUserSeekable)); 92 final float rating = a.getFloat(R.styleable.RatingBar_rating, -1); 93 final float stepSize = a.getFloat(R.styleable.RatingBar_stepSize, -1); 94 a.recycle(); 95 96 if (numStars > 0 && numStars != mNumStars) { 97 setNumStars(numStars); 98 } 99 100 if (stepSize >= 0) { 101 setStepSize(stepSize); 102 } else { 103 setStepSize(0.5f); 104 } 105 106 if (rating >= 0) { 107 setRating(rating); 108 } 109 110 // A touch inside a star fill up to that fractional area (slightly more 111 // than 1 so boundaries round up). 112 mTouchProgressOffset = 1.1f; 113 } 114 115 public RatingBar(Context context, AttributeSet attrs) { 116 this(context, attrs, com.android.internal.R.attr.ratingBarStyle); 117 } 118 119 public RatingBar(Context context) { 120 this(context, null); 121 } 122 123 /** 124 * Sets the listener to be called when the rating changes. 125 * 126 * @param listener The listener. 127 */ 128 public void setOnRatingBarChangeListener(OnRatingBarChangeListener listener) { 129 mOnRatingBarChangeListener = listener; 130 } 131 132 /** 133 * @return The listener (may be null) that is listening for rating change 134 * events. 135 */ 136 public OnRatingBarChangeListener getOnRatingBarChangeListener() { 137 return mOnRatingBarChangeListener; 138 } 139 140 /** 141 * Whether this rating bar should only be an indicator (thus non-changeable 142 * by the user). 143 * 144 * @param isIndicator Whether it should be an indicator. 145 * 146 * @attr ref android.R.styleable#RatingBar_isIndicator 147 */ 148 public void setIsIndicator(boolean isIndicator) { 149 mIsUserSeekable = !isIndicator; 150 setFocusable(!isIndicator); 151 } 152 153 /** 154 * @return Whether this rating bar is only an indicator. 155 * 156 * @attr ref android.R.styleable#RatingBar_isIndicator 157 */ 158 public boolean isIndicator() { 159 return !mIsUserSeekable; 160 } 161 162 /** 163 * Sets the number of stars to show. In order for these to be shown 164 * properly, it is recommended the layout width of this widget be wrap 165 * content. 166 * 167 * @param numStars The number of stars. 168 */ 169 public void setNumStars(final int numStars) { 170 if (numStars <= 0) { 171 return; 172 } 173 174 mNumStars = numStars; 175 176 // This causes the width to change, so re-layout 177 requestLayout(); 178 } 179 180 /** 181 * Returns the number of stars shown. 182 * @return The number of stars shown. 183 */ 184 public int getNumStars() { 185 return mNumStars; 186 } 187 188 /** 189 * Sets the rating (the number of stars filled). 190 * 191 * @param rating The rating to set. 192 */ 193 public void setRating(float rating) { 194 setProgress(Math.round(rating * getProgressPerStar())); 195 } 196 197 /** 198 * Gets the current rating (number of stars filled). 199 * 200 * @return The current rating. 201 */ 202 public float getRating() { 203 return getProgress() / getProgressPerStar(); 204 } 205 206 /** 207 * Sets the step size (granularity) of this rating bar. 208 * 209 * @param stepSize The step size of this rating bar. For example, if 210 * half-star granularity is wanted, this would be 0.5. 211 */ 212 public void setStepSize(float stepSize) { 213 if (stepSize <= 0) { 214 return; 215 } 216 217 final float newMax = mNumStars / stepSize; 218 final int newProgress = (int) (newMax / getMax() * getProgress()); 219 setMax((int) newMax); 220 setProgress(newProgress); 221 } 222 223 /** 224 * Gets the step size of this rating bar. 225 * 226 * @return The step size. 227 */ 228 public float getStepSize() { 229 return (float) getNumStars() / getMax(); 230 } 231 232 /** 233 * @return The amount of progress that fits into a star 234 */ 235 private float getProgressPerStar() { 236 if (mNumStars > 0) { 237 return 1f * getMax() / mNumStars; 238 } else { 239 return 1; 240 } 241 } 242 243 @Override 244 Shape getDrawableShape() { 245 // TODO: Once ProgressBar's TODOs are fixed, this won't be needed 246 return new RectShape(); 247 } 248 249 @Override 250 void onProgressRefresh(float scale, boolean fromUser) { 251 super.onProgressRefresh(scale, fromUser); 252 253 // Keep secondary progress in sync with primary 254 updateSecondaryProgress(getProgress()); 255 256 if (!fromUser) { 257 // Callback for non-user rating changes 258 dispatchRatingChange(false); 259 } 260 } 261 262 /** 263 * The secondary progress is used to differentiate the background of a 264 * partially filled star. This method keeps the secondary progress in sync 265 * with the progress. 266 * 267 * @param progress The primary progress level. 268 */ 269 private void updateSecondaryProgress(int progress) { 270 final float ratio = getProgressPerStar(); 271 if (ratio > 0) { 272 final float progressInStars = progress / ratio; 273 final int secondaryProgress = (int) (Math.ceil(progressInStars) * ratio); 274 setSecondaryProgress(secondaryProgress); 275 } 276 } 277 278 @Override 279 protected synchronized void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 280 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 281 282 if (mSampleTile != null) { 283 // TODO: Once ProgressBar's TODOs are gone, this can be done more 284 // cleanly than mSampleTile 285 final int width = mSampleTile.getWidth() * mNumStars; 286 setMeasuredDimension(resolveSizeAndState(width, widthMeasureSpec, 0), 287 getMeasuredHeight()); 288 } 289 } 290 291 @Override 292 void onStartTrackingTouch() { 293 mProgressOnStartTracking = getProgress(); 294 295 super.onStartTrackingTouch(); 296 } 297 298 @Override 299 void onStopTrackingTouch() { 300 super.onStopTrackingTouch(); 301 302 if (getProgress() != mProgressOnStartTracking) { 303 dispatchRatingChange(true); 304 } 305 } 306 307 @Override 308 void onKeyChange() { 309 super.onKeyChange(); 310 dispatchRatingChange(true); 311 } 312 313 void dispatchRatingChange(boolean fromUser) { 314 if (mOnRatingBarChangeListener != null) { 315 mOnRatingBarChangeListener.onRatingChanged(this, getRating(), 316 fromUser); 317 } 318 } 319 320 @Override 321 public synchronized void setMax(int max) { 322 // Disallow max progress = 0 323 if (max <= 0) { 324 return; 325 } 326 327 super.setMax(max); 328 } 329 330 @Override 331 public void onInitializeAccessibilityEvent(AccessibilityEvent event) { 332 super.onInitializeAccessibilityEvent(event); 333 event.setClassName(RatingBar.class.getName()); 334 } 335 336 @Override 337 public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { 338 super.onInitializeAccessibilityNodeInfo(info); 339 info.setClassName(RatingBar.class.getName()); 340 } 341 } 342
