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      1 /*
      2  * Copyright (C) 2014 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.example.android.activityscenetransitionbasic;
     18 
     19 import android.content.Context;
     20 import android.util.AttributeSet;
     21 import android.widget.FrameLayout;
     22 
     23 /**
     24  * {@link android.widget.FrameLayout} which forces itself to be laid out as square.
     25  */
     26 public class SquareFrameLayout extends FrameLayout {
     27 
     28     public SquareFrameLayout(Context context) {
     29         super(context);
     30     }
     31 
     32     public SquareFrameLayout(Context context, AttributeSet attrs) {
     33         super(context, attrs);
     34     }
     35 
     36     public SquareFrameLayout(Context context, AttributeSet attrs, int defStyleAttr) {
     37         super(context, attrs, defStyleAttr);
     38     }
     39 
     40     public SquareFrameLayout(Context context, AttributeSet attrs,
     41             int defStyleAttr, int defStyleRes) {
     42         super(context, attrs, defStyleAttr, defStyleRes);
     43     }
     44 
     45     @Override
     46     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
     47         final int widthSize = MeasureSpec.getSize(widthMeasureSpec);
     48         final int heightSize = MeasureSpec.getSize(heightMeasureSpec);
     49 
     50         if (widthSize == 0 && heightSize == 0) {
     51             // If there are no constraints on size, let FrameLayout measure
     52             super.onMeasure(widthMeasureSpec, heightMeasureSpec);
     53 
     54             // Now use the smallest of the measured dimensions for both dimensions
     55             final int minSize = Math.min(getMeasuredWidth(), getMeasuredHeight());
     56             setMeasuredDimension(minSize, minSize);
     57             return;
     58         }
     59 
     60         final int size;
     61         if (widthSize == 0 || heightSize == 0) {
     62             // If one of the dimensions has no restriction on size, set both dimensions to be the
     63             // on that does
     64             size = Math.max(widthSize, heightSize);
     65         } else {
     66             // Both dimensions have restrictions on size, set both dimensions to be the
     67             // smallest of the two
     68             size = Math.min(widthSize, heightSize);
     69         }
     70 
     71         final int newMeasureSpec = MeasureSpec.makeMeasureSpec(size, MeasureSpec.EXACTLY);
     72         super.onMeasure(newMeasureSpec, newMeasureSpec);
     73     }
     74 }
     75