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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
17package com.android.internal.widget;
18
19import android.content.Context;
20import android.util.AttributeSet;
21import android.util.Pair;
22import android.view.Gravity;
23import android.view.View;
24import android.view.ViewGroup;
25import android.widget.RemoteViews;
26import android.widget.TextView;
27
28import java.util.ArrayList;
29import java.util.Comparator;
30
31/**
32 * Layout for notification actions that ensures that no action consumes more than their share of
33 * the remaining available width, and the last action consumes the remaining space.
34 */
35@RemoteViews.RemoteView
36public class NotificationActionListLayout extends ViewGroup {
37
38    private int mTotalWidth = 0;
39    private ArrayList<Pair<Integer, TextView>> mMeasureOrderTextViews = new ArrayList<>();
40    private ArrayList<View> mMeasureOrderOther = new ArrayList<>();
41
42    public NotificationActionListLayout(Context context, AttributeSet attrs) {
43        super(context, attrs);
44    }
45
46    @Override
47    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
48        final int N = getChildCount();
49        int textViews = 0;
50        int otherViews = 0;
51        int notGoneChildren = 0;
52
53        View lastNotGoneChild = null;
54        for (int i = 0; i < N; i++) {
55            View c = getChildAt(i);
56            if (c instanceof TextView) {
57                textViews++;
58            } else {
59                otherViews++;
60            }
61            if (c.getVisibility() != GONE) {
62                notGoneChildren++;
63                lastNotGoneChild = c;
64            }
65        }
66
67        // Rebuild the measure order if the number of children changed or the text length of
68        // any of the children changed.
69        boolean needRebuild = false;
70        if (textViews != mMeasureOrderTextViews.size()
71                || otherViews != mMeasureOrderOther.size()) {
72            needRebuild = true;
73        }
74        if (!needRebuild) {
75            final int size = mMeasureOrderTextViews.size();
76            for (int i = 0; i < size; i++) {
77                Pair<Integer, TextView> pair = mMeasureOrderTextViews.get(i);
78                if (pair.first != pair.second.getText().length()) {
79                    needRebuild = true;
80                }
81            }
82        }
83        if (notGoneChildren > 1 && needRebuild) {
84            rebuildMeasureOrder(textViews, otherViews);
85        }
86
87        final boolean constrained =
88                MeasureSpec.getMode(widthMeasureSpec) != MeasureSpec.UNSPECIFIED;
89
90        final int innerWidth = MeasureSpec.getSize(widthMeasureSpec) - mPaddingLeft - mPaddingRight;
91        final int otherSize = mMeasureOrderOther.size();
92        int usedWidth = 0;
93
94        // Optimization: Don't do this if there's only one child.
95        int measuredChildren = 0;
96        for (int i = 0; i < N && notGoneChildren > 1; i++) {
97            // Measure shortest children first. To avoid measuring twice, we approximate by looking
98            // at the text length.
99            View c;
100            if (i < otherSize) {
101                c = mMeasureOrderOther.get(i);
102            } else {
103                c = mMeasureOrderTextViews.get(i - otherSize).second;
104            }
105            if (c.getVisibility() == GONE) {
106                continue;
107            }
108            MarginLayoutParams lp = (MarginLayoutParams) c.getLayoutParams();
109
110            int usedWidthForChild = usedWidth;
111            if (constrained) {
112                // Make sure that this child doesn't consume more than its share of the remaining
113                // total available space. Not used space will benefit subsequent views. Since we
114                // measure in the order of (approx.) size, a large view can still take more than its
115                // share if the others are small.
116                int availableWidth = innerWidth - usedWidth;
117                int maxWidthForChild = availableWidth / (notGoneChildren - measuredChildren);
118
119                usedWidthForChild = innerWidth - maxWidthForChild;
120            }
121
122            measureChildWithMargins(c, widthMeasureSpec, usedWidthForChild,
123                    heightMeasureSpec, 0 /* usedHeight */);
124
125            usedWidth += c.getMeasuredWidth() + lp.rightMargin + lp.leftMargin;
126            measuredChildren++;
127        }
128
129        // Make sure to measure the last child full-width if we didn't use up the entire width,
130        // or we didn't measure yet because there's just one child.
131        if (lastNotGoneChild != null && (constrained && usedWidth < innerWidth
132                || notGoneChildren == 1)) {
133            MarginLayoutParams lp = (MarginLayoutParams) lastNotGoneChild.getLayoutParams();
134            if (notGoneChildren > 1) {
135                // Need to make room, since we already measured this once.
136                usedWidth -= lastNotGoneChild.getMeasuredWidth() + lp.rightMargin + lp.leftMargin;
137            }
138
139            int originalWidth = lp.width;
140            lp.width = LayoutParams.MATCH_PARENT;
141            measureChildWithMargins(lastNotGoneChild, widthMeasureSpec, usedWidth,
142                    heightMeasureSpec, 0 /* usedHeight */);
143            lp.width = originalWidth;
144
145            usedWidth += lastNotGoneChild.getMeasuredWidth() + lp.rightMargin + lp.leftMargin;
146        }
147
148        mTotalWidth = usedWidth + mPaddingRight + mPaddingLeft;
149        setMeasuredDimension(resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec),
150                resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec));
151    }
152
153    private void rebuildMeasureOrder(int capacityText, int capacityOther) {
154        clearMeasureOrder();
155        mMeasureOrderTextViews.ensureCapacity(capacityText);
156        mMeasureOrderOther.ensureCapacity(capacityOther);
157        final int childCount = getChildCount();
158        for (int i = 0; i < childCount; i++) {
159            View c = getChildAt(i);
160            if (c instanceof TextView && ((TextView) c).getText().length() > 0) {
161                mMeasureOrderTextViews.add(Pair.create(((TextView) c).getText().length(),
162                        (TextView)c));
163            } else {
164                mMeasureOrderOther.add(c);
165            }
166        }
167        mMeasureOrderTextViews.sort(MEASURE_ORDER_COMPARATOR);
168    }
169
170    private void clearMeasureOrder() {
171        mMeasureOrderOther.clear();
172        mMeasureOrderTextViews.clear();
173    }
174
175    @Override
176    public void onViewAdded(View child) {
177        super.onViewAdded(child);
178        clearMeasureOrder();
179    }
180
181    @Override
182    public void onViewRemoved(View child) {
183        super.onViewRemoved(child);
184        clearMeasureOrder();
185    }
186
187    @Override
188    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
189        final boolean isLayoutRtl = isLayoutRtl();
190        final int paddingTop = mPaddingTop;
191
192        int childTop;
193        int childLeft;
194
195        // Where bottom of child should go
196        final int height = bottom - top;
197
198        // Space available for child
199        int innerHeight = height - paddingTop - mPaddingBottom;
200
201        final int count = getChildCount();
202
203        final int layoutDirection = getLayoutDirection();
204        switch (Gravity.getAbsoluteGravity(Gravity.START, layoutDirection)) {
205            case Gravity.RIGHT:
206                // mTotalWidth contains the padding already
207                childLeft = mPaddingLeft + right - left - mTotalWidth;
208                break;
209
210            case Gravity.LEFT:
211            default:
212                childLeft = mPaddingLeft;
213                break;
214        }
215
216        int start = 0;
217        int dir = 1;
218        //In case of RTL, start drawing from the last child.
219        if (isLayoutRtl) {
220            start = count - 1;
221            dir = -1;
222        }
223
224        for (int i = 0; i < count; i++) {
225            final int childIndex = start + dir * i;
226            final View child = getChildAt(childIndex);
227            if (child.getVisibility() != GONE) {
228                final int childWidth = child.getMeasuredWidth();
229                final int childHeight = child.getMeasuredHeight();
230
231                final MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();
232
233                childTop = paddingTop + ((innerHeight - childHeight) / 2)
234                            + lp.topMargin - lp.bottomMargin;
235
236                childLeft += lp.leftMargin;
237                child.layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
238                childLeft += childWidth + lp.rightMargin;
239            }
240        }
241    }
242
243    @Override
244    public LayoutParams generateLayoutParams(AttributeSet attrs) {
245        return new MarginLayoutParams(getContext(), attrs);
246    }
247
248    @Override
249    protected LayoutParams generateDefaultLayoutParams() {
250        return new MarginLayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT);
251    }
252
253    @Override
254    protected LayoutParams generateLayoutParams(LayoutParams p) {
255        if (p instanceof MarginLayoutParams) {
256            return new MarginLayoutParams((MarginLayoutParams)p);
257        }
258        return new MarginLayoutParams(p);
259    }
260
261    @Override
262    protected boolean checkLayoutParams(LayoutParams p) {
263        return p instanceof MarginLayoutParams;
264    }
265
266    public static final Comparator<Pair<Integer, TextView>> MEASURE_ORDER_COMPARATOR
267            = (a, b) -> a.first.compareTo(b.first);
268}
269