1/*
2 * Copyright (C) 2011 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.contacts.widget;
18
19import android.content.Context;
20import android.content.res.TypedArray;
21import android.util.AttributeSet;
22import android.view.View;
23import android.view.ViewGroup;
24
25import com.android.contacts.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 */
35public 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