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      1 /*
      2  * Copyright (C) 2010 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.android.internal.widget;
     18 
     19 import android.content.Context;
     20 import android.content.res.TypedArray;
     21 import android.util.AttributeSet;
     22 import android.util.DisplayMetrics;
     23 import android.widget.LinearLayout;
     24 
     25 import static android.view.View.MeasureSpec.*;
     26 import static com.android.internal.R.*;
     27 
     28 /**
     29  * A special layout when measured in AT_MOST will take up a given percentage of
     30  * the available space.
     31  */
     32 public class WeightedLinearLayout extends LinearLayout {
     33     private float mMajorWeightMin;
     34     private float mMinorWeightMin;
     35     private float mMajorWeightMax;
     36     private float mMinorWeightMax;
     37 
     38     public WeightedLinearLayout(Context context) {
     39         super(context);
     40     }
     41 
     42     public WeightedLinearLayout(Context context, AttributeSet attrs) {
     43         super(context, attrs);
     44 
     45         TypedArray a =
     46             context.obtainStyledAttributes(attrs, styleable.WeightedLinearLayout);
     47 
     48         mMajorWeightMin = a.getFloat(styleable.WeightedLinearLayout_majorWeightMin, 0.0f);
     49         mMinorWeightMin = a.getFloat(styleable.WeightedLinearLayout_minorWeightMin, 0.0f);
     50         mMajorWeightMax = a.getFloat(styleable.WeightedLinearLayout_majorWeightMax, 0.0f);
     51         mMinorWeightMax = a.getFloat(styleable.WeightedLinearLayout_minorWeightMax, 0.0f);
     52 
     53         a.recycle();
     54     }
     55 
     56     @Override
     57     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
     58         final DisplayMetrics metrics = getContext().getResources().getDisplayMetrics();
     59         final int screenWidth = metrics.widthPixels;
     60         final boolean isPortrait = screenWidth < metrics.heightPixels;
     61 
     62         final int widthMode = getMode(widthMeasureSpec);
     63 
     64         super.onMeasure(widthMeasureSpec, heightMeasureSpec);
     65 
     66         int width = getMeasuredWidth();
     67         boolean measure = false;
     68 
     69         widthMeasureSpec = MeasureSpec.makeMeasureSpec(width, EXACTLY);
     70 
     71         final float widthWeightMin = isPortrait ? mMinorWeightMin : mMajorWeightMin;
     72         final float widthWeightMax = isPortrait ? mMinorWeightMax : mMajorWeightMax;
     73         if (widthMode == AT_MOST) {
     74             final int weightedMin = (int) (screenWidth * widthWeightMin);
     75             final int weightedMax = (int) (screenWidth * widthWeightMin);
     76             if (widthWeightMin > 0.0f && width < weightedMin) {
     77                 widthMeasureSpec = MeasureSpec.makeMeasureSpec(weightedMin, EXACTLY);
     78                 measure = true;
     79             } else if (widthWeightMax > 0.0f && width > weightedMax) {
     80                 widthMeasureSpec = MeasureSpec.makeMeasureSpec(weightedMax, EXACTLY);
     81                 measure = true;
     82             }
     83         }
     84 
     85         // TODO: Support height?
     86 
     87         if (measure) {
     88             super.onMeasure(widthMeasureSpec, heightMeasureSpec);
     89         }
     90     }
     91 }
     92