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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"); 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 
     15 package com.android.systemui.statusbar.phone;
     16 
     17 import android.annotation.Nullable;
     18 import android.content.Context;
     19 import android.util.AttributeSet;
     20 import android.view.View;
     21 import android.view.ViewGroup;
     22 import android.widget.FrameLayout;
     23 import android.widget.LinearLayout;
     24 
     25 import java.util.ArrayList;
     26 
     27 /**
     28  * Automatically reverses the order of children as they are added.
     29  * Also reverse the width and height values of layout params
     30  */
     31 public class ReverseLinearLayout extends LinearLayout {
     32 
     33     /** If true, the layout is reversed vs. a regular linear layout */
     34     private boolean mIsLayoutReverse;
     35 
     36     /** If true, the layout is opposite to it's natural reversity from the layout direction */
     37     private boolean mIsAlternativeOrder;
     38 
     39     public ReverseLinearLayout(Context context, @Nullable AttributeSet attrs) {
     40         super(context, attrs);
     41     }
     42 
     43     @Override
     44     protected void onFinishInflate() {
     45         super.onFinishInflate();
     46         updateOrder();
     47     }
     48 
     49     @Override
     50     public void addView(View child) {
     51         reverseParams(child.getLayoutParams(), child);
     52         if (mIsLayoutReverse) {
     53             super.addView(child, 0);
     54         } else {
     55             super.addView(child);
     56         }
     57     }
     58 
     59     @Override
     60     public void addView(View child, ViewGroup.LayoutParams params) {
     61         reverseParams(params, child);
     62         if (mIsLayoutReverse) {
     63             super.addView(child, 0, params);
     64         } else {
     65             super.addView(child, params);
     66         }
     67     }
     68 
     69     @Override
     70     public void onRtlPropertiesChanged(int layoutDirection) {
     71         super.onRtlPropertiesChanged(layoutDirection);
     72         updateOrder();
     73     }
     74 
     75     public void setAlternativeOrder(boolean alternative) {
     76         mIsAlternativeOrder = alternative;
     77         updateOrder();
     78     }
     79 
     80     /**
     81      * In landscape, the LinearLayout is not auto mirrored since it is vertical. Therefore we
     82      * have to do it manually
     83      */
     84     private void updateOrder() {
     85         boolean isLayoutRtl = getLayoutDirection() == LAYOUT_DIRECTION_RTL;
     86         boolean isLayoutReverse = isLayoutRtl ^ mIsAlternativeOrder;
     87 
     88         if (mIsLayoutReverse != isLayoutReverse) {
     89             // reversity changed, swap the order of all views.
     90             int childCount = getChildCount();
     91             ArrayList<View> childList = new ArrayList<>(childCount);
     92             for (int i = 0; i < childCount; i++) {
     93                 childList.add(getChildAt(i));
     94             }
     95             removeAllViews();
     96             for (int i = childCount - 1; i >= 0; i--) {
     97                 super.addView(childList.get(i));
     98             }
     99             mIsLayoutReverse = isLayoutReverse;
    100         }
    101     }
    102 
    103     private static void reverseParams(ViewGroup.LayoutParams params, View child) {
    104         if (child instanceof Reversable) {
    105             ((Reversable) child).reverse();
    106         }
    107         if (child.getPaddingLeft() == child.getPaddingRight()
    108                 && child.getPaddingTop() == child.getPaddingBottom()) {
    109             child.setPadding(child.getPaddingTop(), child.getPaddingLeft(),
    110                     child.getPaddingTop(), child.getPaddingLeft());
    111         }
    112         if (params == null) {
    113             return;
    114         }
    115         int width = params.width;
    116         params.width = params.height;
    117         params.height = width;
    118     }
    119 
    120     public interface Reversable {
    121         void reverse();
    122     }
    123 
    124     public static class ReverseFrameLayout extends FrameLayout implements Reversable {
    125 
    126         public ReverseFrameLayout(Context context) {
    127             super(context);
    128         }
    129 
    130         @Override
    131         public void reverse() {
    132             for (int i = 0; i < getChildCount(); i++) {
    133                 View child = getChildAt(i);
    134                 reverseParams(child.getLayoutParams(), child);
    135             }
    136         }
    137     }
    138 
    139 }
    140