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Android example source code file (WeightedLinearLayout.java)

This example Android source code file (WeightedLinearLayout.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" TM.

Java - Android tags/keywords

android, at_most, attributeset, content, displaymetrics, exactly, override, typedarray, ui, util, utilities, utils, weightedlinearlayout

The WeightedLinearLayout.java Android example source code

/*
 * Copyright (C) 2010 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 com.android.internal.widget;

import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.widget.LinearLayout;

import static android.view.View.MeasureSpec.*;
import static com.android.internal.R.*;

/**
 * A special layout when measured in AT_MOST will take up a given percentage of
 * the available space.
 */
public class WeightedLinearLayout extends LinearLayout {
    private float mMajorWeight;
    private float mMinorWeight;

    public WeightedLinearLayout(Context context) {
        super(context);
    }

    public WeightedLinearLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
        
        TypedArray a = 
            context.obtainStyledAttributes(attrs, styleable.WeightedLinearLayout);

        mMajorWeight = a.getFloat(styleable.WeightedLinearLayout_majorWeight, 0.0f);
        mMinorWeight = a.getFloat(styleable.WeightedLinearLayout_minorWeight, 0.0f);
        
        a.recycle();
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        final DisplayMetrics metrics = getContext().getResources().getDisplayMetrics();
        final int screenWidth = metrics.widthPixels;
        final boolean isPortrait = screenWidth < metrics.heightPixels;

        final int widthMode = getMode(widthMeasureSpec);

        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        int width = getMeasuredWidth();
        int height = getMeasuredHeight();
        boolean measure = false;

        widthMeasureSpec = MeasureSpec.makeMeasureSpec(width, EXACTLY);
        heightMeasureSpec = MeasureSpec.makeMeasureSpec(height, EXACTLY);

        final float widthWeight = isPortrait ? mMinorWeight : mMajorWeight;
        if (widthMode == AT_MOST && widthWeight > 0.0f) {
            if (width < (screenWidth * widthWeight)) {
                widthMeasureSpec = MeasureSpec.makeMeasureSpec((int) (screenWidth * widthWeight),
                        EXACTLY);
                measure = true;
            }
        }

        // TODO: Support height?

        if (measure) {
            super.onMeasure(widthMeasureSpec, heightMeasureSpec);            
        }
    }
}

Other Android examples (source code examples)

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