1/*
2 * Copyright (C) 2015 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.packageinstaller.permission.ui;
18
19import android.content.Context;
20import android.util.AttributeSet;
21import android.view.Gravity;
22import android.view.View;
23import android.widget.LinearLayout;
24import com.android.packageinstaller.R;
25
26/**
27 * An extension of LinearLayout that automatically switches to vertical
28 * orientation when it can't fit its child views horizontally.
29 */
30public class ButtonBarLayout extends LinearLayout {
31    /** Whether the current configuration allows stacking. */
32    private boolean mAllowStacking;
33
34    private int mLastWidthSize = -1;
35
36    public ButtonBarLayout(Context context, AttributeSet attrs) {
37        super(context, attrs);
38        mAllowStacking = true;
39    }
40
41    public void setAllowStacking(boolean allowStacking) {
42        if (mAllowStacking != allowStacking) {
43            mAllowStacking = allowStacking;
44            if (!mAllowStacking && getOrientation() == LinearLayout.VERTICAL) {
45                setStacked(false);
46            }
47            requestLayout();
48        }
49    }
50
51    @Override
52    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
53        final int widthSize = MeasureSpec.getSize(widthMeasureSpec);
54
55        if (mAllowStacking) {
56            if (widthSize > mLastWidthSize && isStacked()) {
57                // We're being measured wider this time, try un-stacking.
58                setStacked(false);
59            }
60
61            mLastWidthSize = widthSize;
62        }
63
64        boolean needsRemeasure = false;
65
66        // If we're not stacked, make sure the measure spec is AT_MOST rather
67        // than EXACTLY. This ensures that we'll still get TOO_SMALL so that we
68        // know to stack the buttons.
69        final int initialWidthMeasureSpec;
70        if (!isStacked() && MeasureSpec.getMode(widthMeasureSpec) == MeasureSpec.EXACTLY) {
71            initialWidthMeasureSpec = MeasureSpec.makeMeasureSpec(widthSize, MeasureSpec.AT_MOST);
72
73            // We'll need to remeasure again to fill excess space.
74            needsRemeasure = true;
75        } else {
76            initialWidthMeasureSpec = widthMeasureSpec;
77        }
78
79        super.onMeasure(initialWidthMeasureSpec, heightMeasureSpec);
80
81        if (mAllowStacking && !isStacked()) {
82            final int measuredWidth = getMeasuredWidthAndState();
83            final int measuredWidthState = measuredWidth & MEASURED_STATE_MASK;
84            if (measuredWidthState == MEASURED_STATE_TOO_SMALL) {
85                setStacked(true);
86
87                // Measure again in the new orientation.
88                needsRemeasure = true;
89            }
90        }
91
92        if (needsRemeasure) {
93            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
94        }
95    }
96
97    private void setStacked(boolean stacked) {
98        setOrientation(stacked ? LinearLayout.VERTICAL : LinearLayout.HORIZONTAL);
99        setGravity(stacked ? Gravity.END : Gravity.BOTTOM);
100
101        final View spacer = findViewById(R.id.spacer);
102        if (spacer != null) {
103            spacer.setVisibility(stacked ? View.GONE : View.INVISIBLE);
104        }
105
106        // Reverse the child order. This is specific to the Material button
107        // bar's layout XML and will probably not generalize.
108        final int childCount = getChildCount();
109        for (int i = childCount - 2; i >= 0; i--) {
110            bringChildToFront(getChildAt(i));
111        }
112    }
113
114    private boolean isStacked() {
115        return getOrientation() == LinearLayout.VERTICAL;
116    }
117}
118