/* * Copyright (C) 2015 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package android.support.percent; import android.content.Context; import android.content.res.TypedArray; import android.util.AttributeSet; import android.view.ViewGroup; import android.widget.FrameLayout; /** * Subclass of {@link android.widget.FrameLayout} that supports percentage based dimensions and * margins. * * You can specify dimension or a margin of child by using attributes with "Percent" suffix. Follow * this example: * *
 * <android.support.percent.PercentFrameLayout
 *         xmlns:android="http://schemas.android.com/apk/res/android"
 *         xmlns:app="http://schemas.android.com/apk/res-auto"
 *         android:layout_width="match_parent"
 *         android:layout_height="match_parent">
 *     <ImageView
 *         app:layout_widthPercent="50%"
 *         app:layout_heightPercent="50%"
 *         app:layout_marginTopPercent="25%"
 *         app:layout_marginLeftPercent="25%"/>
 * </android.support.percent.PercentFrameLayout>
 * 
* * The attributes that you can use are: * * * It is not necessary to specify {@code layout_width/height} if you specify {@code * layout_widthPercent.} However, if you want the view to be able to take up more space than what * percentage value permits, you can add {@code layout_width/height="wrap_content"}. In that case * if the percentage size is too small for the View's content, it will be resized using * {@code wrap_content} rule. * *

* You can also make one dimension be a fraction of the other by setting only width or height and * using {@code layout_aspectRatio} for the second one to be calculated automatically. For * example, if you would like to achieve 16:9 aspect ratio, you can write: *

 *     android:layout_width="300dp"
 *     app:layout_aspectRatio="178%"
 * 
* This will make the aspect ratio 16:9 (1.78:1) with the width fixed at 300dp and height adjusted * accordingly. */ public class PercentFrameLayout extends FrameLayout { private final PercentLayoutHelper mHelper = new PercentLayoutHelper(this); public PercentFrameLayout(Context context) { super(context); } public PercentFrameLayout(Context context, AttributeSet attrs) { super(context, attrs); } public PercentFrameLayout(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); } @Override protected LayoutParams generateDefaultLayoutParams() { return new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT); } @Override public LayoutParams generateLayoutParams(AttributeSet attrs) { return new LayoutParams(getContext(), attrs); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { mHelper.adjustChildren(widthMeasureSpec, heightMeasureSpec); super.onMeasure(widthMeasureSpec, heightMeasureSpec); if (mHelper.handleMeasuredStateTooSmall()) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); } } @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { super.onLayout(changed, left, top, right, bottom); mHelper.restoreOriginalParams(); } public static class LayoutParams extends FrameLayout.LayoutParams implements PercentLayoutHelper.PercentLayoutParams { private PercentLayoutHelper.PercentLayoutInfo mPercentLayoutInfo; public LayoutParams(Context c, AttributeSet attrs) { super(c, attrs); mPercentLayoutInfo = PercentLayoutHelper.getPercentLayoutInfo(c, attrs); } public LayoutParams(int width, int height) { super(width, height); } public LayoutParams(int width, int height, int gravity) { super(width, height, gravity); } public LayoutParams(ViewGroup.LayoutParams source) { super(source); } public LayoutParams(MarginLayoutParams source) { super(source); } public LayoutParams(FrameLayout.LayoutParams source) { super((MarginLayoutParams) source); gravity = source.gravity; } public LayoutParams(LayoutParams source) { this((FrameLayout.LayoutParams) source); mPercentLayoutInfo = source.mPercentLayoutInfo; } @Override public PercentLayoutHelper.PercentLayoutInfo getPercentLayoutInfo() { if (mPercentLayoutInfo == null) { mPercentLayoutInfo = new PercentLayoutHelper.PercentLayoutInfo(); } return mPercentLayoutInfo; } @Override protected void setBaseAttributes(TypedArray a, int widthAttr, int heightAttr) { PercentLayoutHelper.fetchWidthAndHeight(this, a, widthAttr, heightAttr); } } }