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      1 /*
      2  * Copyright (C) 2016 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 com.android.internal.widget;
     18 
     19 import com.android.internal.R;
     20 
     21 import android.annotation.Nullable;
     22 import android.content.Context;
     23 import android.content.res.TypedArray;
     24 import android.graphics.Canvas;
     25 import android.util.AttributeSet;
     26 import android.view.RemotableViewMethod;
     27 import android.view.View;
     28 import android.view.ViewGroup;
     29 import android.widget.RemoteViews;
     30 
     31 /**
     32  * A custom-built layout for the Notification.MessagingStyle.
     33  *
     34  * Evicts children until they all fit.
     35  */
     36 @RemoteViews.RemoteView
     37 public class MessagingLinearLayout extends ViewGroup {
     38 
     39     /**
     40      * Spacing to be applied between views.
     41      */
     42     private int mSpacing;
     43 
     44     /**
     45      * The maximum height allowed.
     46      */
     47     private int mMaxHeight;
     48 
     49     private int mIndentLines;
     50 
     51     /**
     52      * Id of the child that's also visible in the contracted layout.
     53      */
     54     private int mContractedChildId;
     55 
     56     public MessagingLinearLayout(Context context, @Nullable AttributeSet attrs) {
     57         super(context, attrs);
     58 
     59         final TypedArray a = context.obtainStyledAttributes(attrs,
     60                 R.styleable.MessagingLinearLayout, 0,
     61                 0);
     62 
     63         final int N = a.getIndexCount();
     64         for (int i = 0; i < N; i++) {
     65             int attr = a.getIndex(i);
     66             switch (attr) {
     67                 case R.styleable.MessagingLinearLayout_maxHeight:
     68                     mMaxHeight = a.getDimensionPixelSize(i, 0);
     69                     break;
     70                 case R.styleable.MessagingLinearLayout_spacing:
     71                     mSpacing = a.getDimensionPixelSize(i, 0);
     72                     break;
     73             }
     74         }
     75 
     76         if (mMaxHeight <= 0) {
     77             throw new IllegalStateException(
     78                     "MessagingLinearLayout: Must specify positive maxHeight");
     79         }
     80 
     81         a.recycle();
     82     }
     83 
     84 
     85     @Override
     86     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
     87         // This is essentially a bottom-up linear layout that only adds children that fit entirely
     88         // up to a maximum height.
     89 
     90         switch (MeasureSpec.getMode(heightMeasureSpec)) {
     91             case MeasureSpec.AT_MOST:
     92                 heightMeasureSpec = MeasureSpec.makeMeasureSpec(
     93                         Math.min(mMaxHeight, MeasureSpec.getSize(heightMeasureSpec)),
     94                         MeasureSpec.AT_MOST);
     95                 break;
     96             case MeasureSpec.UNSPECIFIED:
     97                 heightMeasureSpec = MeasureSpec.makeMeasureSpec(
     98                         mMaxHeight,
     99                         MeasureSpec.AT_MOST);
    100                 break;
    101             case MeasureSpec.EXACTLY:
    102                 break;
    103         }
    104         final int targetHeight = MeasureSpec.getSize(heightMeasureSpec);
    105         final int count = getChildCount();
    106 
    107         for (int i = 0; i < count; ++i) {
    108             final View child = getChildAt(i);
    109             final LayoutParams lp = (LayoutParams) child.getLayoutParams();
    110             lp.hide = true;
    111         }
    112 
    113         int totalHeight = mPaddingTop + mPaddingBottom;
    114         boolean first = true;
    115 
    116         // Starting from the bottom: we measure every view as if it were the only one. If it still
    117         // fits, we take it, otherwise we stop there.
    118         for (int i = count - 1; i >= 0 && totalHeight < targetHeight; i--) {
    119             if (getChildAt(i).getVisibility() == GONE) {
    120                 continue;
    121             }
    122             final View child = getChildAt(i);
    123             LayoutParams lp = (LayoutParams) getChildAt(i).getLayoutParams();
    124 
    125             if (child instanceof ImageFloatingTextView) {
    126                 // Pretend we need the image padding for all views, we don't know which
    127                 // one will end up needing to do this (might end up not using all the space,
    128                 // but calculating this exactly would be more expensive).
    129                 ((ImageFloatingTextView) child).setNumIndentLines(mIndentLines);
    130             }
    131 
    132             measureChildWithMargins(child, widthMeasureSpec, 0, heightMeasureSpec, 0);
    133 
    134             final int childHeight = child.getMeasuredHeight();
    135             int newHeight = Math.max(totalHeight, totalHeight + childHeight + lp.topMargin +
    136                     lp.bottomMargin + (first ? 0 : mSpacing));
    137             first = false;
    138 
    139             if (newHeight <= targetHeight) {
    140                 totalHeight = newHeight;
    141                 lp.hide = false;
    142             } else {
    143                 break;
    144             }
    145         }
    146 
    147         // Now that we know which views to take, fix up the indents and see what width we get.
    148         int measuredWidth = mPaddingLeft + mPaddingRight;
    149         int imageLines = mIndentLines;
    150         for (int i = 0; i < count; i++) {
    151             final View child = getChildAt(i);
    152             final LayoutParams lp = (LayoutParams) child.getLayoutParams();
    153 
    154             if (child.getVisibility() == GONE || lp.hide) {
    155                 continue;
    156             }
    157 
    158             if (child instanceof ImageFloatingTextView) {
    159                 ImageFloatingTextView textChild = (ImageFloatingTextView) child;
    160                 if (imageLines == 2 && textChild.getLineCount() > 2) {
    161                     // HACK: If we need indent for two lines, and they're coming from the same
    162                     // view, we need extra spacing to compensate for the lack of margins,
    163                     // so add an extra line of indent.
    164                     imageLines = 3;
    165                 }
    166                 boolean changed = textChild.setNumIndentLines(Math.max(0, imageLines));
    167                 if (changed) {
    168                     measureChildWithMargins(child, widthMeasureSpec, 0, heightMeasureSpec, 0);
    169                 }
    170                 imageLines -= textChild.getLineCount();
    171             }
    172 
    173             measuredWidth = Math.max(measuredWidth,
    174                     child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin
    175                             + mPaddingLeft + mPaddingRight);
    176         }
    177 
    178 
    179         setMeasuredDimension(
    180                 resolveSize(Math.max(getSuggestedMinimumWidth(), measuredWidth),
    181                         widthMeasureSpec),
    182                 resolveSize(Math.max(getSuggestedMinimumHeight(), totalHeight),
    183                         heightMeasureSpec));
    184     }
    185 
    186     @Override
    187     protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
    188         final int paddingLeft = mPaddingLeft;
    189 
    190         int childTop;
    191 
    192         // Where right end of child should go
    193         final int width = right - left;
    194         final int childRight = width - mPaddingRight;
    195 
    196         final int layoutDirection = getLayoutDirection();
    197         final int count = getChildCount();
    198 
    199         childTop = mPaddingTop;
    200 
    201         boolean first = true;
    202 
    203         for (int i = 0; i < count; i++) {
    204             final View child = getChildAt(i);
    205             final LayoutParams lp = (LayoutParams) child.getLayoutParams();
    206 
    207             if (child.getVisibility() == GONE || lp.hide) {
    208                 continue;
    209             }
    210 
    211             final int childWidth = child.getMeasuredWidth();
    212             final int childHeight = child.getMeasuredHeight();
    213 
    214             int childLeft;
    215             if (layoutDirection == LAYOUT_DIRECTION_RTL) {
    216                 childLeft = childRight - childWidth - lp.rightMargin;
    217             } else {
    218                 childLeft = paddingLeft + lp.leftMargin;
    219             }
    220 
    221             if (!first) {
    222                 childTop += mSpacing;
    223             }
    224 
    225             childTop += lp.topMargin;
    226             child.layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
    227 
    228             childTop += childHeight + lp.bottomMargin;
    229 
    230             first = false;
    231         }
    232     }
    233 
    234     @Override
    235     protected boolean drawChild(Canvas canvas, View child, long drawingTime) {
    236         final LayoutParams lp = (LayoutParams) child.getLayoutParams();
    237         if (lp.hide) {
    238             return true;
    239         }
    240         return super.drawChild(canvas, child, drawingTime);
    241     }
    242 
    243     @Override
    244     public LayoutParams generateLayoutParams(AttributeSet attrs) {
    245         return new LayoutParams(mContext, attrs);
    246     }
    247 
    248     @Override
    249     protected LayoutParams generateDefaultLayoutParams() {
    250         return new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
    251 
    252     }
    253 
    254     @Override
    255     protected LayoutParams generateLayoutParams(ViewGroup.LayoutParams lp) {
    256         LayoutParams copy = new LayoutParams(lp.width, lp.height);
    257         if (lp instanceof MarginLayoutParams) {
    258             copy.copyMarginsFrom((MarginLayoutParams) lp);
    259         }
    260         return copy;
    261     }
    262 
    263     /**
    264      * Sets how many lines should be indented to avoid a floating image.
    265      */
    266     @RemotableViewMethod
    267     public void setNumIndentLines(int numberLines) {
    268         mIndentLines = numberLines;
    269     }
    270 
    271     /**
    272      * Set id of the child that's also visible in the contracted layout.
    273      */
    274     @RemotableViewMethod
    275     public void setContractedChildId(int contractedChildId) {
    276         mContractedChildId = contractedChildId;
    277     }
    278 
    279     /**
    280      * Get id of the child that's also visible in the contracted layout.
    281      */
    282     public int getContractedChildId() {
    283         return mContractedChildId;
    284     }
    285 
    286     public static class LayoutParams extends MarginLayoutParams {
    287 
    288         boolean hide = false;
    289 
    290         public LayoutParams(Context c, AttributeSet attrs) {
    291             super(c, attrs);
    292         }
    293 
    294         public LayoutParams(int width, int height) {
    295             super(width, height);
    296         }
    297     }
    298 }
    299