src/com/android/camera/SoundPlayer.java

/*
 * Copyright (C) 2011 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.camera;

import android.content.res.AssetFileDescriptor;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.util.Log;

import java.io.IOException;

/**
 * Plays an AssetFileDescriptor, but does all the hard work on another thread so
 * that any slowness with preparing or loading doesn't block the calling thread.
 */
public class SoundPlayer implements Runnable {
    private static final String TAG = "SoundPlayer";
    private Thread mThread;
    private MediaPlayer mPlayer;
    private int mPlayCount = 0;
    private boolean mExit;
    private AssetFileDescriptor mAfd;
    private int mAudioStreamType;

    @Override
    public void run() {
        while(true) {
            try {
                if (mPlayer == null) {
                    MediaPlayer player = new MediaPlayer();
                    player.setAudioStreamType(mAudioStreamType);
                    player.setDataSource(mAfd.getFileDescriptor(), mAfd.getStartOffset(),
                            mAfd.getLength());
                    player.setLooping(false);
                    player.prepare();
                    mPlayer = player;
                    mAfd.close();
                    mAfd = null;
                }
                synchronized (this) {
                    while(true) {
                        if (mExit) {
                            return;
                        } else if (mPlayCount <= 0) {
                            wait();
                        } else {
                            mPlayCount--;
                            break;
                        }
                    }
                }
                mPlayer.start();
            } catch (Exception e) {
                Log.e(TAG, "Error playing sound", e);
            }
        }
    }

    public SoundPlayer(AssetFileDescriptor afd) {
        mAfd = afd;
        mAudioStreamType = AudioManager.STREAM_MUSIC;
    }

    public SoundPlayer(AssetFileDescriptor afd, boolean enforceAudible) {
        mAfd = afd;
        if (enforceAudible) {
            mAudioStreamType = 7; // AudioManager.STREAM_SYSTEM_ENFORCED; currently hidden API.
        } else {
            mAudioStreamType = AudioManager.STREAM_MUSIC;
        }
    }

    public void play() {
        if (mThread == null) {
            mThread = new Thread(this);
            mThread.start();
        }
        synchronized (this) {
            mPlayCount++;
            notifyAll();
        }
    }

    public void release() {
        if (mThread != null) {
            synchronized (this) {
                mExit = true;
                notifyAll();
            }
            try {
                mThread.join();
            } catch (InterruptedException e) {
            }
            mThread = null;
        }
        if (mAfd != null) {
            try {
                mAfd.close();
            } catch(IOException e) {
            }
            mAfd = null;
        }
        if (mPlayer != null) {
            mPlayer.release();
            mPlayer = null;
        }
    }
}