src/com/android/camera/SoundPlayer.java

/*
 * Copyright (C) 2014 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.Context;
import android.media.AudioManager;
import android.media.SoundPool;
import android.util.SparseIntArray;

import com.android.camera.util.ApiHelper;

/**
 * Loads a plays custom sounds. For playing system-standard sounds for various
 * camera actions, please refer to {@link SoundClips}.
 */
public class SoundPlayer {
    private final Context mAppContext;
    private final SoundPool mSoundPool;
    /** Keeps a mapping from sound resource ID to sound ID */
    private final SparseIntArray mResourceToSoundId = new SparseIntArray();
    private boolean mIsReleased = false;

    /**
     * Construct a new sound player.
     */
    public SoundPlayer(Context appContext) {
        mAppContext = appContext;
        final int audioType = getAudioTypeForSoundPool();
        mSoundPool = new SoundPool(1 /* max streams */, audioType, 0 /* quality */);
    }

    /**
     * Load the sound from a resource.
     */
    public void loadSound(int resourceId) {
        int soundId = mSoundPool.load(mAppContext, resourceId, 1/* priority */);
        mResourceToSoundId.put(resourceId, soundId);
    }

    /**
     * Play the sound with the given resource. The resource has to be loaded
     * before it can be played, otherwise an exception will be thrown.
     */
    public void play(int resourceId, float volume) {
        Integer soundId = mResourceToSoundId.get(resourceId);
        if (soundId == null) {
            throw new IllegalStateException("Sound not loaded. Must call #loadSound first.");
        }
        mSoundPool.play(soundId, volume, volume, 0 /* priority */, 0 /* loop */, 1 /* rate */);
    }

    /**
     * Unload the given sound if it's not needed anymore to release memory.
     */
    public void unloadSound(int resourceId) {
        Integer soundId = mResourceToSoundId.get(resourceId);
        if (soundId == null) {
            throw new IllegalStateException("Sound not loaded. Must call #loadSound first.");
        }
        mSoundPool.unload(soundId);
    }

    /**
     * Call this if you don't need the SoundPlayer anymore. All memory will be
     * released and the object cannot be re-used.
     */
    public void release() {
        mIsReleased = true;
        mSoundPool.release();
    }

    public boolean isReleased() {
        return mIsReleased;
    }

    private static int getAudioTypeForSoundPool() {
        // STREAM_SYSTEM_ENFORCED is hidden API.
        return ApiHelper.getIntFieldIfExists(AudioManager.class,
                "STREAM_SYSTEM_ENFORCED", null, AudioManager.STREAM_RING);
    }
}