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 android.annotation.Nullable;
20 import android.content.Context;
21 import android.content.res.TypedArray;
22 import android.graphics.Canvas;
23 import android.util.AttributeSet;
24 import android.view.RemotableViewMethod;
25 import android.view.View;
26 import android.view.ViewGroup;
27 import android.widget.RemoteViews;
28 
29 import com.android.internal.R;
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     private int mMaxDisplayedLines = Integer.MAX_VALUE;
45 
46     private MessagingLayout mMessagingLayout;
47 
MessagingLinearLayout(Context context, @Nullable AttributeSet attrs)48     public MessagingLinearLayout(Context context, @Nullable AttributeSet attrs) {
49         super(context, attrs);
50 
51         final TypedArray a = context.obtainStyledAttributes(attrs,
52                 R.styleable.MessagingLinearLayout, 0,
53                 0);
54 
55         final int N = a.getIndexCount();
56         for (int i = 0; i < N; i++) {
57             int attr = a.getIndex(i);
58             switch (attr) {
59                 case R.styleable.MessagingLinearLayout_spacing:
60                     mSpacing = a.getDimensionPixelSize(i, 0);
61                     break;
62             }
63         }
64 
65         a.recycle();
66     }
67 
68     @Override
onMeasure(int widthMeasureSpec, int heightMeasureSpec)69     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
70         // This is essentially a bottom-up linear layout that only adds children that fit entirely
71         // up to a maximum height.
72         int targetHeight = MeasureSpec.getSize(heightMeasureSpec);
73         switch (MeasureSpec.getMode(heightMeasureSpec)) {
74             case MeasureSpec.UNSPECIFIED:
75                 targetHeight = Integer.MAX_VALUE;
76                 break;
77         }
78 
79         // Now that we know which views to take, fix up the indents and see what width we get.
80         int measuredWidth = mPaddingLeft + mPaddingRight;
81         final int count = getChildCount();
82         int totalHeight;
83         for (int i = 0; i < count; ++i) {
84             final View child = getChildAt(i);
85             final LayoutParams lp = (LayoutParams) child.getLayoutParams();
86             lp.hide = true;
87         }
88 
89         totalHeight = mPaddingTop + mPaddingBottom;
90         boolean first = true;
91         int linesRemaining = mMaxDisplayedLines;
92         // Starting from the bottom: we measure every view as if it were the only one. If it still
93         // fits, we take it, otherwise we stop there.
94         for (int i = count - 1; i >= 0 && totalHeight < targetHeight; i--) {
95             if (getChildAt(i).getVisibility() == GONE) {
96                 continue;
97             }
98             final View child = getChildAt(i);
99             LayoutParams lp = (LayoutParams) getChildAt(i).getLayoutParams();
100             MessagingChild messagingChild = null;
101             int spacing = mSpacing;
102             if (child instanceof MessagingChild) {
103                 messagingChild = (MessagingChild) child;
104                 messagingChild.setMaxDisplayedLines(linesRemaining);
105                 spacing += messagingChild.getExtraSpacing();
106             }
107             spacing = first ? 0 : spacing;
108             measureChildWithMargins(child, widthMeasureSpec, 0, heightMeasureSpec, totalHeight
109                     - mPaddingTop - mPaddingBottom + spacing);
110 
111             final int childHeight = child.getMeasuredHeight();
112             int newHeight = Math.max(totalHeight, totalHeight + childHeight + lp.topMargin +
113                     lp.bottomMargin + spacing);
114             first = false;
115             int measureType = MessagingChild.MEASURED_NORMAL;
116             if (messagingChild != null) {
117                 measureType = messagingChild.getMeasuredType();
118                 linesRemaining -= messagingChild.getConsumedLines();
119             }
120             boolean isShortened = measureType == MessagingChild.MEASURED_SHORTENED;
121             boolean isTooSmall = measureType == MessagingChild.MEASURED_TOO_SMALL;
122             if (newHeight <= targetHeight && !isTooSmall) {
123                 totalHeight = newHeight;
124                 measuredWidth = Math.max(measuredWidth,
125                         child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin
126                                 + mPaddingLeft + mPaddingRight);
127                 lp.hide = false;
128                 if (isShortened || linesRemaining <= 0) {
129                     break;
130                 }
131             } else {
132                 break;
133             }
134         }
135 
136         setMeasuredDimension(
137                 resolveSize(Math.max(getSuggestedMinimumWidth(), measuredWidth),
138                         widthMeasureSpec),
139                 Math.max(getSuggestedMinimumHeight(), totalHeight));
140     }
141 
142     @Override
onLayout(boolean changed, int left, int top, int right, int bottom)143     protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
144         final int paddingLeft = mPaddingLeft;
145 
146         int childTop;
147 
148         // Where right end of child should go
149         final int width = right - left;
150         final int childRight = width - mPaddingRight;
151 
152         final int layoutDirection = getLayoutDirection();
153         final int count = getChildCount();
154 
155         childTop = mPaddingTop;
156 
157         boolean first = true;
158         final boolean shown = isShown();
159         for (int i = 0; i < count; i++) {
160             final View child = getChildAt(i);
161             if (child.getVisibility() == GONE) {
162                 continue;
163             }
164             final LayoutParams lp = (LayoutParams) child.getLayoutParams();
165             MessagingChild messagingChild = (MessagingChild) child;
166 
167             final int childWidth = child.getMeasuredWidth();
168             final int childHeight = child.getMeasuredHeight();
169 
170             int childLeft;
171             if (layoutDirection == LAYOUT_DIRECTION_RTL) {
172                 childLeft = childRight - childWidth - lp.rightMargin;
173             } else {
174                 childLeft = paddingLeft + lp.leftMargin;
175             }
176             if (lp.hide) {
177                 if (shown && lp.visibleBefore) {
178                     // We still want to lay out the child to have great animations
179                     child.layout(childLeft, childTop, childLeft + childWidth,
180                             childTop + lp.lastVisibleHeight);
181                     messagingChild.hideAnimated();
182                 }
183                 lp.visibleBefore = false;
184                 continue;
185             } else {
186                 lp.visibleBefore = true;
187                 lp.lastVisibleHeight = childHeight;
188             }
189 
190             if (!first) {
191                 childTop += mSpacing;
192             }
193 
194             childTop += lp.topMargin;
195             child.layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
196 
197             childTop += childHeight + lp.bottomMargin;
198 
199             first = false;
200         }
201     }
202 
203     @Override
drawChild(Canvas canvas, View child, long drawingTime)204     protected boolean drawChild(Canvas canvas, View child, long drawingTime) {
205         final LayoutParams lp = (LayoutParams) child.getLayoutParams();
206         if (lp.hide) {
207             MessagingChild messagingChild = (MessagingChild) child;
208             if (!messagingChild.isHidingAnimated()) {
209                 return true;
210             }
211         }
212         return super.drawChild(canvas, child, drawingTime);
213     }
214 
215     @Override
generateLayoutParams(AttributeSet attrs)216     public LayoutParams generateLayoutParams(AttributeSet attrs) {
217         return new LayoutParams(mContext, attrs);
218     }
219 
220     @Override
generateDefaultLayoutParams()221     protected LayoutParams generateDefaultLayoutParams() {
222         return new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
223 
224     }
225 
226     @Override
generateLayoutParams(ViewGroup.LayoutParams lp)227     protected LayoutParams generateLayoutParams(ViewGroup.LayoutParams lp) {
228         LayoutParams copy = new LayoutParams(lp.width, lp.height);
229         if (lp instanceof MarginLayoutParams) {
230             copy.copyMarginsFrom((MarginLayoutParams) lp);
231         }
232         return copy;
233     }
234 
isGone(View view)235     public static boolean isGone(View view) {
236         if (view.getVisibility() == View.GONE) {
237             return true;
238         }
239         final ViewGroup.LayoutParams lp = view.getLayoutParams();
240         if (lp instanceof MessagingLinearLayout.LayoutParams
241                 && ((MessagingLinearLayout.LayoutParams) lp).hide) {
242             return true;
243         }
244         return false;
245     }
246 
247     /**
248      * Sets how many lines should be displayed at most
249      */
250     @RemotableViewMethod
setMaxDisplayedLines(int numberLines)251     public void setMaxDisplayedLines(int numberLines) {
252         mMaxDisplayedLines = numberLines;
253     }
254 
setMessagingLayout(MessagingLayout layout)255     public void setMessagingLayout(MessagingLayout layout) {
256         mMessagingLayout = layout;
257     }
258 
getMessagingLayout()259     public MessagingLayout getMessagingLayout() {
260         return mMessagingLayout;
261     }
262 
263     public interface MessagingChild {
264         int MEASURED_NORMAL = 0;
265         int MEASURED_SHORTENED = 1;
266         int MEASURED_TOO_SMALL = 2;
267 
getMeasuredType()268         int getMeasuredType();
getConsumedLines()269         int getConsumedLines();
setMaxDisplayedLines(int lines)270         void setMaxDisplayedLines(int lines);
hideAnimated()271         void hideAnimated();
isHidingAnimated()272         boolean isHidingAnimated();
getExtraSpacing()273         default int getExtraSpacing() {
274             return 0;
275         }
276     }
277 
278     public static class LayoutParams extends MarginLayoutParams {
279 
280         public boolean hide = false;
281         public boolean visibleBefore = false;
282         public int lastVisibleHeight;
283 
LayoutParams(Context c, AttributeSet attrs)284         public LayoutParams(Context c, AttributeSet attrs) {
285             super(c, attrs);
286         }
287 
LayoutParams(int width, int height)288         public LayoutParams(int width, int height) {
289             super(width, height);
290         }
291     }
292 }
293