1 /*
2  * Copyright 2018 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 androidx.percentlayout.widget;
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  * &lt;androidx.percentlayout.widget.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"&gt
38  *     &lt;ImageView
39  *         app:layout_widthPercent="50%"
40  *         app:layout_heightPercent="50%"
41  *         app:layout_marginTopPercent="25%"
42  *         app:layout_marginLeftPercent="25%"/&gt
43  * &lt;/androidx.percentlayout.widget.PercentRelativeLayout&gt
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  * @deprecated consider using ConstraintLayout and associated layouts instead. The following shows
78  * how to replicate the functionality of percentage layouts with a ConstraintLayout. The Guidelines
79  * are used to define each percentage break point, and then a Button view is stretched to fill
80  * the gap:
81  *
82  * <pre class="prettyprint">
83  * &lt;androidx.constraintlayout.widget.ConstraintLayout
84  *         xmlns:android="http://schemas.android.com/apk/res/android"
85  *         xmlns:app="http://schemas.android.com/apk/res-auto"
86  *         android:layout_width="match_parent"
87  *         android:layout_height="match_parent"&gt
88  *
89  *     &lt;androidx.constraintlayout.widget.Guideline
90  *         android:layout_width="wrap_content"
91  *         android:layout_height="wrap_content"
92  *         android:id="@+id/left_guideline"
93  *         app:layout_constraintGuide_percent=".15"
94  *         android:orientation="vertical"/&gt
95  *
96  *     &lt;androidx.constraintlayout.widget.Guideline
97  *         android:layout_width="wrap_content"
98  *         android:layout_height="wrap_content"
99  *         android:id="@+id/right_guideline"
100  *         app:layout_constraintGuide_percent=".85"
101  *         android:orientation="vertical"/&gt
102  *
103  *     &lt;androidx.constraintlayout.widget.Guideline
104  *         android:layout_width="wrap_content"
105  *         android:layout_height="wrap_content"
106  *         android:id="@+id/top_guideline"
107  *         app:layout_constraintGuide_percent=".15"
108  *         android:orientation="horizontal"/&gt
109  *
110  *     &lt;androidx.constraintlayout.widget.Guideline
111  *         android:layout_width="wrap_content"
112  *         android:layout_height="wrap_content"
113  *         android:id="@+id/bottom_guideline"
114  *         app:layout_constraintGuide_percent=".85"
115  *         android:orientation="horizontal"/&gt
116  *
117  *     &lt;Button
118  *         android:text="Button"
119  *         android:layout_width="0dp"
120  *         android:layout_height="0dp"
121  *         android:id="@+id/button"
122  *         app:layout_constraintLeft_toLeftOf="@+id/left_guideline"
123  *         app:layout_constraintRight_toRightOf="@+id/right_guideline"
124  *         app:layout_constraintTop_toTopOf="@+id/top_guideline"
125  *         app:layout_constraintBottom_toBottomOf="@+id/bottom_guideline" /&gt
126  *
127  * &lt;/androidx.constraintlayout.widget.ConstraintLayout&gt
128  */
129 @Deprecated
130 public class PercentRelativeLayout extends RelativeLayout {
131     private final PercentLayoutHelper mHelper = new PercentLayoutHelper(this);
132 
PercentRelativeLayout(Context context)133     public PercentRelativeLayout(Context context) {
134         super(context);
135     }
136 
PercentRelativeLayout(Context context, AttributeSet attrs)137     public PercentRelativeLayout(Context context, AttributeSet attrs) {
138         super(context, attrs);
139     }
140 
PercentRelativeLayout(Context context, AttributeSet attrs, int defStyle)141     public PercentRelativeLayout(Context context, AttributeSet attrs, int defStyle) {
142         super(context, attrs, defStyle);
143     }
144 
145     @Override
generateDefaultLayoutParams()146     protected LayoutParams generateDefaultLayoutParams() {
147         return new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
148     }
149 
150     @Override
generateLayoutParams(AttributeSet attrs)151     public LayoutParams generateLayoutParams(AttributeSet attrs) {
152         return new LayoutParams(getContext(), attrs);
153     }
154 
155     @Override
onMeasure(int widthMeasureSpec, int heightMeasureSpec)156     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
157         mHelper.adjustChildren(widthMeasureSpec, heightMeasureSpec);
158         super.onMeasure(widthMeasureSpec, heightMeasureSpec);
159         if (mHelper.handleMeasuredStateTooSmall()) {
160             super.onMeasure(widthMeasureSpec, heightMeasureSpec);
161         }
162     }
163 
164     @Override
onLayout(boolean changed, int left, int top, int right, int bottom)165     protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
166         super.onLayout(changed, left, top, right, bottom);
167         mHelper.restoreOriginalParams();
168     }
169 
170     /**
171      * @deprecated this class is deprecated along with its parent class.
172      */
173     @Deprecated
174     public static class LayoutParams extends RelativeLayout.LayoutParams
175             implements PercentLayoutHelper.PercentLayoutParams {
176         private PercentLayoutHelper.PercentLayoutInfo mPercentLayoutInfo;
177 
LayoutParams(Context c, AttributeSet attrs)178         public LayoutParams(Context c, AttributeSet attrs) {
179             super(c, attrs);
180             mPercentLayoutInfo = PercentLayoutHelper.getPercentLayoutInfo(c, attrs);
181         }
182 
LayoutParams(int width, int height)183         public LayoutParams(int width, int height) {
184             super(width, height);
185         }
186 
LayoutParams(ViewGroup.LayoutParams source)187         public LayoutParams(ViewGroup.LayoutParams source) {
188             super(source);
189         }
190 
LayoutParams(MarginLayoutParams source)191         public LayoutParams(MarginLayoutParams source) {
192             super(source);
193         }
194 
195         @Override
getPercentLayoutInfo()196         public PercentLayoutHelper.PercentLayoutInfo getPercentLayoutInfo() {
197             if (mPercentLayoutInfo == null) {
198                 mPercentLayoutInfo = new PercentLayoutHelper.PercentLayoutInfo();
199             }
200 
201             return mPercentLayoutInfo;
202         }
203 
204         @Override
setBaseAttributes(TypedArray a, int widthAttr, int heightAttr)205         protected void setBaseAttributes(TypedArray a, int widthAttr, int heightAttr) {
206             PercentLayoutHelper.fetchWidthAndHeight(this, a, widthAttr, heightAttr);
207         }
208     }
209 }
210