CheckableRelativeLayout.java

/*
 * This source is part of the
 *      _____  ___   ____
 *  __ / / _ \/ _ | / __/___  _______ _
 * / // / , _/ __ |/ _/_/ _ \/ __/ _ `/
 * \___/_/|_/_/ |_/_/ (_)___/_/  \_, /
 *                              /___/
 * repository.
 *
 * Copyright (C) 2013 Benoit 'BoD' Lubek (BoD@JRAF.org)
 * Copyright (C) 2008 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 org.jraf.android.util.ui.checkable;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.Checkable;
import android.widget.CompoundButton.OnCheckedChangeListener;
import android.widget.RelativeLayout;

/**
 * A special variation of RelativeLayout that can be used as a checkable object.
 * This allows it to be used as the top-level view of a list view item, which
 * also supports checking. Otherwise, it works identically to a RelativeLayout.
 * Note: this was taken from the Android Open Source Project (platform/packages/apps/music/src/com/android/music/CheckableRelativeLayout.java).
 */
public class CheckableRelativeLayout extends RelativeLayout implements Checkable {
    private boolean mChecked;
    private OnCheckedChangeListener mOnCheckedChangeListener;
    private volatile boolean mBroadcasting;

    private static final int[] CHECKED_STATE_SET = { android.R.attr.state_checked };

    public CheckableRelativeLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    protected int[] onCreateDrawableState(int extraSpace) {
        final int[] drawableState = super.onCreateDrawableState(extraSpace + 1);
        if (isChecked()) {
            mergeDrawableStates(drawableState, CHECKED_STATE_SET);
        }
        return drawableState;
    }

    @Override
    public void toggle() {
        setChecked(!mChecked);
    }

    @Override
    public boolean isChecked() {
        return mChecked;
    }

    @Override
    public void setChecked(boolean checked) {
        setChecked(checked, true);
    }

    public void setChecked(boolean checked, boolean notifyListener) {
        if (mChecked != checked) {
            mChecked = checked;
            refreshDrawableState();

            if (mBroadcasting) {
                // Avoid infinite recursions if setChecked() is called from a listener
                return;
            }

            if (notifyListener && mOnCheckedChangeListener != null) {
                // XXX Normally we would pass this view as the first argument, unfortunately
                // the OnCheckedChangeListener interface wants a CompoundButton here :(
                // Pass null instead.

                mBroadcasting = true;

                mOnCheckedChangeListener.onCheckedChanged(null, mChecked);

                mBroadcasting = false;
            }
        }
    }

    @Override
    public boolean performClick() {
        if (isClickable()) toggle();
        return super.performClick();
    }

    /**
     * Register a callback to be invoked when the checked state of this button
     * changes.
     * 
     * @param listener the callback to call on checked state change
     */
    public void setOnCheckedChangeListener(OnCheckedChangeListener listener) {
        mOnCheckedChangeListener = listener;
    }
}