1/*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
5 * except in compliance with the License. You may obtain a copy of the License at
6 *
7 *      http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software distributed under the
10 * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
11 * KIND, either express or implied. See the License for the specific language governing
12 * permissions and limitations under the License.
13 */
14
15package com.android.systemui.statusbar.phone;
16
17import android.annotation.Nullable;
18import android.content.Context;
19import android.util.AttributeSet;
20import android.view.Gravity;
21import android.view.View;
22import android.view.ViewGroup;
23import android.widget.LinearLayout;
24import android.widget.RelativeLayout;
25
26import java.util.ArrayList;
27
28/**
29 * Automatically reverses the order of children as they are added.
30 * Also reverse the width and height values of layout params
31 */
32public class ReverseLinearLayout extends LinearLayout {
33
34    /** If true, the layout is reversed vs. a regular linear layout */
35    private boolean mIsLayoutReverse;
36
37    /** If true, the layout is opposite to it's natural reversity from the layout direction */
38    private boolean mIsAlternativeOrder;
39
40    public ReverseLinearLayout(Context context, @Nullable AttributeSet attrs) {
41        super(context, attrs);
42    }
43
44    @Override
45    protected void onFinishInflate() {
46        super.onFinishInflate();
47        updateOrder();
48    }
49
50    @Override
51    public void addView(View child) {
52        reverseParams(child.getLayoutParams(), child, mIsLayoutReverse);
53        if (mIsLayoutReverse) {
54            super.addView(child, 0);
55        } else {
56            super.addView(child);
57        }
58    }
59
60    @Override
61    public void addView(View child, ViewGroup.LayoutParams params) {
62        reverseParams(params, child, mIsLayoutReverse);
63        if (mIsLayoutReverse) {
64            super.addView(child, 0, params);
65        } else {
66            super.addView(child, params);
67        }
68    }
69
70    @Override
71    public void onRtlPropertiesChanged(int layoutDirection) {
72        super.onRtlPropertiesChanged(layoutDirection);
73        updateOrder();
74    }
75
76    public void setAlternativeOrder(boolean alternative) {
77        mIsAlternativeOrder = alternative;
78        updateOrder();
79    }
80
81    /**
82     * In landscape, the LinearLayout is not auto mirrored since it is vertical. Therefore we
83     * have to do it manually
84     */
85    private void updateOrder() {
86        boolean isLayoutRtl = getLayoutDirection() == LAYOUT_DIRECTION_RTL;
87        boolean isLayoutReverse = isLayoutRtl ^ mIsAlternativeOrder;
88
89        if (mIsLayoutReverse != isLayoutReverse) {
90            // reversity changed, swap the order of all views.
91            int childCount = getChildCount();
92            ArrayList<View> childList = new ArrayList<>(childCount);
93            for (int i = 0; i < childCount; i++) {
94                childList.add(getChildAt(i));
95            }
96            removeAllViews();
97            for (int i = childCount - 1; i >= 0; i--) {
98                final View child = childList.get(i);
99                super.addView(child);
100            }
101            mIsLayoutReverse = isLayoutReverse;
102        }
103    }
104
105    private static void reverseParams(ViewGroup.LayoutParams params, View child,
106            boolean isLayoutReverse) {
107        if (child instanceof Reversable) {
108            ((Reversable) child).reverse(isLayoutReverse);
109        }
110        if (child.getPaddingLeft() == child.getPaddingRight()
111                && child.getPaddingTop() == child.getPaddingBottom()) {
112            child.setPadding(child.getPaddingTop(), child.getPaddingLeft(),
113                    child.getPaddingTop(), child.getPaddingLeft());
114        }
115        if (params == null) {
116            return;
117        }
118        int width = params.width;
119        params.width = params.height;
120        params.height = width;
121    }
122
123    public interface Reversable {
124        void reverse(boolean isLayoutReverse);
125    }
126
127    public static class ReverseRelativeLayout extends RelativeLayout implements Reversable {
128
129        public ReverseRelativeLayout(Context context) {
130            super(context);
131        }
132
133        @Override
134        public void reverse(boolean isLayoutReverse) {
135            updateGravity(isLayoutReverse);
136            reverseGroup(this, isLayoutReverse);
137        }
138
139        private int mDefaultGravity = Gravity.NO_GRAVITY;
140        public void setDefaultGravity(int gravity) {
141            mDefaultGravity = gravity;
142        }
143
144        public void updateGravity(boolean isLayoutReverse) {
145            // Flip gravity if top of bottom is used
146            if (mDefaultGravity != Gravity.TOP && mDefaultGravity != Gravity.BOTTOM) return;
147
148            // Use the default (intended for 270 LTR and 90 RTL) unless layout is otherwise
149            int gravityToApply = mDefaultGravity;
150            if (isLayoutReverse) {
151                gravityToApply = mDefaultGravity == Gravity.TOP ? Gravity.BOTTOM : Gravity.TOP;
152            }
153
154            if (getGravity() != gravityToApply) setGravity(gravityToApply);
155        }
156    }
157
158    private static void reverseGroup(ViewGroup group, boolean isLayoutReverse) {
159        for (int i = 0; i < group.getChildCount(); i++) {
160            final View child = group.getChildAt(i);
161            reverseParams(child.getLayoutParams(), child, isLayoutReverse);
162
163            // Recursively reverse all children
164            if (child instanceof ViewGroup) {
165                reverseGroup((ViewGroup) child, isLayoutReverse);
166            }
167        }
168    }
169
170}
171