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      1 /*
      2  * Copyright (C) 2012 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.contacts.common.widget;
     18 
     19 import android.content.Context;
     20 import android.content.res.TypedArray;
     21 import android.util.AttributeSet;
     22 import android.view.View;
     23 import android.view.ViewGroup;
     24 
     25 import com.android.contacts.common.R;
     26 
     27 /**
     28  * Layout that calculates its height based on its width, or vice versa (depending on the set
     29  * {@link #setDirection(Direction)}. The factor is specified in {@link #setRatio(float)}.
     30  * <p>For {@link Direction#heightToWidth}: width := height * factor</p>
     31  * <p>For {@link Direction#widthToHeight}: height := width * factor</p>
     32  * <p>Only one child is allowed; if more are required, another ViewGroup can be used as the direct
     33  * child of this layout.</p>
     34  */
     35 public class ProportionalLayout extends ViewGroup {
     36     /** Specifies whether the width should be calculated based on the height or vice-versa  */
     37     public enum Direction {
     38         widthToHeight("widthToHeight"),
     39         heightToWidth("heightToWidth");
     40 
     41         public final String XmlName;
     42 
     43         private Direction(String xmlName) {
     44             XmlName = xmlName;
     45         }
     46 
     47         /**
     48          * Parses the given direction string and returns the Direction instance. This
     49          * should be used when inflating from xml
     50          */
     51         public static Direction parse(String value) {
     52             if (widthToHeight.XmlName.equals(value)) {
     53                 return Direction.widthToHeight;
     54             } else if (heightToWidth.XmlName.equals(value)) {
     55                 return Direction.heightToWidth;
     56             } else {
     57                 throw new IllegalStateException("direction must be either " +
     58                         widthToHeight.XmlName + " or " + heightToWidth.XmlName);
     59             }
     60         }
     61     }
     62 
     63     private Direction mDirection;
     64     private float mRatio;
     65 
     66     public ProportionalLayout(Context context) {
     67         super(context);
     68     }
     69 
     70     public ProportionalLayout(Context context, AttributeSet attrs) {
     71         super(context, attrs);
     72         initFromAttributes(context, attrs);
     73     }
     74 
     75     public ProportionalLayout(Context context, AttributeSet attrs, int defStyle) {
     76         super(context, attrs, defStyle);
     77         initFromAttributes(context, attrs);
     78     }
     79 
     80     private void initFromAttributes(Context context, AttributeSet attrs) {
     81         TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ProportionalLayout);
     82 
     83         mDirection = Direction.parse(a.getString(R.styleable.ProportionalLayout_direction));
     84         mRatio = a.getFloat(R.styleable.ProportionalLayout_ratio, 1.0f);
     85 
     86         a.recycle();
     87     }
     88 
     89     @Override
     90     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
     91         if (getChildCount() != 1) {
     92             throw new IllegalStateException("ProportionalLayout requires exactly one child");
     93         }
     94 
     95         final View child = getChildAt(0);
     96 
     97         // Do a first pass to get the optimal size
     98         measureChild(child, widthMeasureSpec, heightMeasureSpec);
     99         final int childWidth = child.getMeasuredWidth();
    100         final int childHeight = child.getMeasuredHeight();
    101 
    102         final int width;
    103         final int height;
    104         if (mDirection == Direction.heightToWidth) {
    105             width = Math.round(childHeight * mRatio);
    106             height = childHeight;
    107         } else {
    108             width = childWidth;
    109             height = Math.round(childWidth * mRatio);
    110         }
    111 
    112         // Do a second pass so that all children are informed of the new size
    113         measureChild(child,
    114                 MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY),
    115                 MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY));
    116 
    117         setMeasuredDimension(
    118                 resolveSize(width, widthMeasureSpec), resolveSize(height, heightMeasureSpec));
    119     }
    120 
    121     @Override
    122     protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
    123         if (getChildCount() != 1) {
    124             throw new IllegalStateException("ProportionalLayout requires exactly one child");
    125         }
    126 
    127         final View child = getChildAt(0);
    128         child.layout(0, 0, right-left, bottom-top);
    129     }
    130 
    131     public Direction getDirection() {
    132         return mDirection;
    133     }
    134 
    135     public void setDirection(Direction direction) {
    136         mDirection = direction;
    137     }
    138 
    139     public float getRatio() {
    140         return mRatio;
    141     }
    142 
    143     public void setRatio(float ratio) {
    144         mRatio = ratio;
    145     }
    146 }
    147