sdk/sources/android-25/com/android/internal/widget/WeightedLinearLayout.java

   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 }