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 
Direction(String xmlName)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          */
parse(String value)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 
ProportionalLayout(Context context)66     public ProportionalLayout(Context context) {
67         super(context);
68     }
69 
ProportionalLayout(Context context, AttributeSet attrs)70     public ProportionalLayout(Context context, AttributeSet attrs) {
71         super(context, attrs);
72         initFromAttributes(context, attrs);
73     }
74 
ProportionalLayout(Context context, AttributeSet attrs, int defStyle)75     public ProportionalLayout(Context context, AttributeSet attrs, int defStyle) {
76         super(context, attrs, defStyle);
77         initFromAttributes(context, attrs);
78     }
79 
initFromAttributes(Context context, AttributeSet attrs)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
onMeasure(int widthMeasureSpec, int heightMeasureSpec)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
onLayout(boolean changed, int left, int top, int right, int bottom)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 
getDirection()131     public Direction getDirection() {
132         return mDirection;
133     }
134 
setDirection(Direction direction)135     public void setDirection(Direction direction) {
136         mDirection = direction;
137     }
138 
getRatio()139     public float getRatio() {
140         return mRatio;
141     }
142 
setRatio(float ratio)143     public void setRatio(float ratio) {
144         mRatio = ratio;
145     }
146 }
147