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Android example source code file (ToggleButton.java)

This example Android source code file (ToggleButton.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, attributeset, charsequence, compoundbutton, content, drawing, graphics, layerdrawable, no_alpha, override, paint, togglebutton, typedarray, ui

The ToggleButton.java Android example source code

/*
 * Copyright (C) 2007 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.widget;


import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.LayerDrawable;
import android.util.AttributeSet;

/**
 * Displays checked/unchecked states as a button
 * with a "light" indicator and by default accompanied with the text "ON" or "OFF".
 * 
 * @attr ref android.R.styleable#ToggleButton_textOn
 * @attr ref android.R.styleable#ToggleButton_textOff
 * @attr ref android.R.styleable#ToggleButton_disabledAlpha
 */
public class ToggleButton extends CompoundButton {
    private CharSequence mTextOn;
    private CharSequence mTextOff;
    
    private Drawable mIndicatorDrawable;

    private static final int NO_ALPHA = 0xFF;
    private float mDisabledAlpha;
    
    public ToggleButton(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        
        TypedArray a =
            context.obtainStyledAttributes(
                    attrs, com.android.internal.R.styleable.ToggleButton, defStyle, 0);
        mTextOn = a.getText(com.android.internal.R.styleable.ToggleButton_textOn);
        mTextOff = a.getText(com.android.internal.R.styleable.ToggleButton_textOff);
        mDisabledAlpha = a.getFloat(com.android.internal.R.styleable.ToggleButton_disabledAlpha, 0.5f);
        syncTextState();
        a.recycle();
    }

    public ToggleButton(Context context, AttributeSet attrs) {
        this(context, attrs, com.android.internal.R.attr.buttonStyleToggle);
    }

    public ToggleButton(Context context) {
        this(context, null);
    }

    @Override
    public void setChecked(boolean checked) {
        super.setChecked(checked);
        
        syncTextState();
    }

    private void syncTextState() {
        boolean checked = isChecked();
        if (checked && mTextOn != null) {
            setText(mTextOn);
        } else if (!checked && mTextOff != null) {
            setText(mTextOff);
        }
    }

    /**
     * Returns the text for when the button is in the checked state.
     * 
     * @return The text.
     */
    public CharSequence getTextOn() {
        return mTextOn;
    }

    /**
     * Sets the text for when the button is in the checked state.
     *  
     * @param textOn The text.
     */
    public void setTextOn(CharSequence textOn) {
        mTextOn = textOn;
    }

    /**
     * Returns the text for when the button is not in the checked state.
     * 
     * @return The text.
     */
    public CharSequence getTextOff() {
        return mTextOff;
    }

    /**
     * Sets the text for when the button is not in the checked state.
     * 
     * @param textOff The text.
     */
    public void setTextOff(CharSequence textOff) {
        mTextOff = textOff;
    }

    @Override
    protected void onFinishInflate() {
        super.onFinishInflate();
        
        updateReferenceToIndicatorDrawable(getBackground());
    }

    @Override
    public void setBackgroundDrawable(Drawable d) {
        super.setBackgroundDrawable(d);
        
        updateReferenceToIndicatorDrawable(d);
    }

    private void updateReferenceToIndicatorDrawable(Drawable backgroundDrawable) {
        if (backgroundDrawable instanceof LayerDrawable) {
            LayerDrawable layerDrawable = (LayerDrawable) backgroundDrawable;
            mIndicatorDrawable =
                    layerDrawable.findDrawableByLayerId(com.android.internal.R.id.toggle);
        }
    }
    
    @Override
    protected void drawableStateChanged() {
        super.drawableStateChanged();
        
        if (mIndicatorDrawable != null) {
            mIndicatorDrawable.setAlpha(isEnabled() ? NO_ALPHA : (int) (NO_ALPHA * mDisabledAlpha));
        }
    }
    
}

Other Android examples (source code examples)

Here is a short list of links related to this Android ToggleButton.java source code file:

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