1 /* 2 * Copyright (C) 2015 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 android.support.percent; 18 19 import android.content.Context; 20 import android.content.res.TypedArray; 21 import android.util.AttributeSet; 22 import android.view.ViewGroup; 23 import android.widget.RelativeLayout; 24 25 /** 26 * Subclass of {@link android.widget.RelativeLayout} that supports percentage based dimensions and 27 * margins. 28 * 29 * You can specify dimension or a margin of child by using attributes with "Percent" suffix. Follow 30 * this example: 31 * 32 * <pre class="prettyprint"> 33 * <android.support.percent.PercentRelativeLayout 34 * xmlns:android="http://schemas.android.com/apk/res/android" 35 * xmlns:app="http://schemas.android.com/apk/res-auto" 36 * android:layout_width="match_parent" 37 * android:layout_height="match_parent"> 38 * <ImageView 39 * app:layout_widthPercent="50%" 40 * app:layout_heightPercent="50%" 41 * app:layout_marginTopPercent="25%" 42 * app:layout_marginLeftPercent="25%"/> 43 * </android.support.percent.PercentFrameLayout> 44 * </pre> 45 * 46 * The attributes that you can use are: 47 * <ul> 48 * <li>{@code layout_widthPercent} 49 * <li>{@code layout_heightPercent} 50 * <li>{@code layout_marginPercent} 51 * <li>{@code layout_marginLeftPercent} 52 * <li>{@code layout_marginTopPercent} 53 * <li>{@code layout_marginRightPercent} 54 * <li>{@code layout_marginBottomPercent} 55 * <li>{@code layout_marginStartPercent} 56 * <li>{@code layout_marginEndPercent} 57 * <li>{@code layout_aspectRatio} 58 * </ul> 59 * 60 * It is not necessary to specify {@code layout_width/height} if you specify {@code 61 * layout_widthPercent.} However, if you want the view to be able to take up more space than what 62 * percentage value permits, you can add {@code layout_width/height="wrap_content"}. In that case 63 * if the percentage size is too small for the View's content, it will be resized using 64 * {@code wrap_content} rule. 65 * 66 * <p> 67 * You can also make one dimension be a fraction of the other by setting only width or height and 68 * using {@code layout_aspectRatio} for the second one to be calculated automatically. For 69 * example, if you would like to achieve 16:9 aspect ratio, you can write: 70 * <pre class="prettyprint"> 71 * android:layout_width="300dp" 72 * app:layout_aspectRatio="178%" 73 * </pre> 74 * This will make the aspect ratio 16:9 (1.78:1) with the width fixed at 300dp and height adjusted 75 * accordingly. 76 */ 77 public class PercentRelativeLayout extends RelativeLayout { 78 private final PercentLayoutHelper mHelper = new PercentLayoutHelper(this); 79 PercentRelativeLayout(Context context)80 public PercentRelativeLayout(Context context) { 81 super(context); 82 } 83 PercentRelativeLayout(Context context, AttributeSet attrs)84 public PercentRelativeLayout(Context context, AttributeSet attrs) { 85 super(context, attrs); 86 } 87 PercentRelativeLayout(Context context, AttributeSet attrs, int defStyle)88 public PercentRelativeLayout(Context context, AttributeSet attrs, int defStyle) { 89 super(context, attrs, defStyle); 90 } 91 92 @Override generateDefaultLayoutParams()93 protected LayoutParams generateDefaultLayoutParams() { 94 return new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT); 95 } 96 97 @Override generateLayoutParams(AttributeSet attrs)98 public LayoutParams generateLayoutParams(AttributeSet attrs) { 99 return new LayoutParams(getContext(), attrs); 100 } 101 102 @Override onMeasure(int widthMeasureSpec, int heightMeasureSpec)103 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 104 mHelper.adjustChildren(widthMeasureSpec, heightMeasureSpec); 105 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 106 if (mHelper.handleMeasuredStateTooSmall()) { 107 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 108 } 109 } 110 111 @Override onLayout(boolean changed, int left, int top, int right, int bottom)112 protected void onLayout(boolean changed, int left, int top, int right, int bottom) { 113 super.onLayout(changed, left, top, right, bottom); 114 mHelper.restoreOriginalParams(); 115 } 116 117 public static class LayoutParams extends RelativeLayout.LayoutParams 118 implements PercentLayoutHelper.PercentLayoutParams { 119 private PercentLayoutHelper.PercentLayoutInfo mPercentLayoutInfo; 120 LayoutParams(Context c, AttributeSet attrs)121 public LayoutParams(Context c, AttributeSet attrs) { 122 super(c, attrs); 123 mPercentLayoutInfo = PercentLayoutHelper.getPercentLayoutInfo(c, attrs); 124 } 125 LayoutParams(int width, int height)126 public LayoutParams(int width, int height) { 127 super(width, height); 128 } 129 LayoutParams(ViewGroup.LayoutParams source)130 public LayoutParams(ViewGroup.LayoutParams source) { 131 super(source); 132 } 133 LayoutParams(MarginLayoutParams source)134 public LayoutParams(MarginLayoutParams source) { 135 super(source); 136 } 137 138 @Override getPercentLayoutInfo()139 public PercentLayoutHelper.PercentLayoutInfo getPercentLayoutInfo() { 140 if (mPercentLayoutInfo == null) { 141 mPercentLayoutInfo = new PercentLayoutHelper.PercentLayoutInfo(); 142 } 143 144 return mPercentLayoutInfo; 145 } 146 147 @Override setBaseAttributes(TypedArray a, int widthAttr, int heightAttr)148 protected void setBaseAttributes(TypedArray a, int widthAttr, int heightAttr) { 149 PercentLayoutHelper.fetchWidthAndHeight(this, a, widthAttr, heightAttr); 150 } 151 } 152 } 153