src/com/android/music/CheckableRelativeLayout.java

/*
 * 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 com.android.music;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.Checkable;
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.
 */
public class CheckableRelativeLayout extends RelativeLayout implements Checkable {
    private boolean mChecked;

    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;
    }

    public void toggle() {
        setChecked(!mChecked);
    }
    
    public boolean isChecked() {
        return mChecked;
    }

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