VisualizerController.java

/*
 This file is part of Subsonic.

 Subsonic is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 Subsonic is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with Subsonic.  If not, see <http://www.gnu.org/licenses/>.

 Copyright 2011 (C) Sindre Mehus
 */
package github.madmarty.madsonic.audiofx;

import android.content.Context;
import android.media.MediaPlayer;
import android.media.audiofx.Visualizer;
import github.madmarty.madsonic.util.Logger;

/**
 * Backward-compatible wrapper for {@link Visualizer}, which is API Level 9.
 *
 * @author Sindre Mehus
 * @version $Id$
 */
public class VisualizerController {

    private static final Logger LOG = new Logger(VisualizerController.class);
    private static final int PREFERRED_CAPTURE_SIZE = 128; // Must be a power of two.

    private Visualizer visualizer;
	private boolean released = false;
	private int audioSessionId = 0;

    // Class initialization fails when this throws an exception.
    static {
        try {
            Class.forName("android.media.audiofx.Visualizer");
        } catch (Exception ex) {
            throw new RuntimeException(ex);
        }
    }

    /**
     * Throws an exception if the {@link Visualizer} class is not available.
     */
    public static void checkAvailable() throws Throwable {
        // Calling here forces class initialization.
    }

    public VisualizerController(Context context, MediaPlayer mediaPlayer) {
        try {
			audioSessionId = mediaPlayer.getAudioSessionId();
            visualizer = new Visualizer(audioSessionId);
        } catch (Throwable x) {
            LOG.warn("Failed to create visualizer.", x);
        }

        if (visualizer != null) {
            int[] captureSizeRange = Visualizer.getCaptureSizeRange();
            int captureSize = Math.max(PREFERRED_CAPTURE_SIZE, captureSizeRange[0]);
            captureSize = Math.min(captureSize, captureSizeRange[1]);
            visualizer.setCaptureSize(captureSize);
        }
    }

    public boolean isAvailable() {
        return visualizer != null;
    }

    public boolean isEnabled() {
        return isAvailable() && visualizer.getEnabled();
    }

    public void release() {
        if (isAvailable()) {
            visualizer.release();
			released = true;
        }
    }

    public Visualizer getVisualizer() {
		if(released) {
			released = false;
			try {
				visualizer = new Visualizer(audioSessionId);
			} catch (Throwable x) {
				visualizer = null;
				LOG.warn("Failed to create visualizer.", x);
			}
		}
		
        return visualizer;
    }
}