在Android开发中有时候需要用到播放声音操作，在android API 的media包中有三种方式可供我们选择，它们分别是Ringtone，SoundPool，MediaPlayer。因为在我目前的项目中暂时用不到播放很长的音频文件，只需要播放一些简短的提示音，所以在这篇博文中我只是简单的记录下。
- 1.Ringtone.java
- 2.SoundPool.java
- 3.MediaPlayer.java
- 4.demo
- 5.bug record
1.Ringtone.java
关于Ringtone的介绍。
package android.media;
/**
* Ringtone provides a quick method for playing a ringtone, notification, or
* other similar types of sounds.
* <p>
* For ways of retrieving {@link Ringtone} objects or to show a ringtone
* picker, see {@link RingtoneManager}.
*
* @see RingtoneManager
*/
public class Ringtone {}2.SoundPool.java
关于SoundPool的介绍。
/**
* The SoundPool class manages and plays audio resources for applications.
*
* <p>A SoundPool is a collection of samples that can be loaded into memory
* from a resource inside the APK or from a file in the file system. The
* SoundPool library uses the MediaPlayer service to decode the audio
* into a raw 16-bit PCM mono or stereo stream. This allows applications
* to ship with compressed streams without having to suffer the CPU load
* and latency of decompressing during playback.</p>
*
* <p>In addition to low-latency playback, SoundPool can also manage the number
* of audio streams being rendered at once. When the SoundPool object is
* constructed, the maxStreams parameter sets the maximum number of streams
* that can be played at a time from this single SoundPool. SoundPool tracks
* the number of active streams. If the maximum number of streams is exceeded,
* SoundPool will automatically stop a previously playing stream based first
* on priority and then by age within that priority. Limiting the maximum
* number of streams helps to cap CPU loading and reducing the likelihood that
* audio mixing will impact visuals or UI performance.</p>
*
* <p>Sounds can be looped by setting a non-zero loop value. A value of -1
* causes the sound to loop forever. In this case, the application must
* explicitly call the stop() function to stop the sound. Any other non-zero
* value will cause the sound to repeat the specified number of times, e.g.
* a value of 3 causes the sound to play a total of 4 times.</p>
*
* <p>The playback rate can also be changed. A playback rate of 1.0 causes
* the sound to play at its original frequency (resampled, if necessary,
* to the hardware output frequency). A playback rate of 2.0 causes the
* sound to play at twice its original frequency, and a playback rate of
* 0.5 causes it to play at half its original frequency. The playback
* rate range is 0.5 to 2.0.</p>
*
* <p>Priority runs low to high, i.e. higher numbers are higher priority.
* Priority is used when a call to play() would cause the number of active
* streams to exceed the value established by the maxStreams parameter when
* the SoundPool was created. In this case, the stream allocator will stop
* the lowest priority stream. If there are multiple streams with the same
* low priority, it will choose the oldest stream to stop. In the case
* where the priority of the new stream is lower than all the active
* streams, the new sound will not play and the play() function will return
* a streamID of zero.</p>
*
* <p>Let's examine a typical use case: A game consists of several levels of
* play. For each level, there is a set of unique sounds that are used only
* by that level. In this case, the game logic should create a new SoundPool
* object when the first level is loaded. The level data itself might contain
* the list of sounds to be used by this level. The loading logic iterates
* through the list of sounds calling the appropriate SoundPool.load()
* function. This should typically be done early in the process to allow time
* for decompressing the audio to raw PCM format before they are needed for
* playback.</p>
*
* <p>Once the sounds are loaded and play has started, the application can
* trigger sounds by calling SoundPool.play(). Playing streams can be
* paused or resumed, and the application can also alter the pitch by
* adjusting the playback rate in real-time for doppler or synthesis
* effects.</p>
*
* <p>Note that since streams can be stopped due to resource constraints, the
* streamID is a reference to a particular instance of a stream. If the stream
* is stopped to allow a higher priority stream to play, the stream is no
* longer be valid. However, the application is allowed to call methods on
* the streamID without error. This may help simplify program logic since
* the application need not concern itself with the stream lifecycle.</p>
*
* <p>In our example, when the player has completed the level, the game
* logic should call SoundPool.release() to release all the native resources
* in use and then set the SoundPool reference to null. If the player starts
* another level, a new SoundPool is created, sounds are loaded, and play
* resumes.</p>
*/
public class SoundPool {}3.MediaPlayer.java
package android.media;
/**
* MediaPlayer class can be used to control playback
* of audio/video files and streams. An example on how to use the methods in
* this class can be found in {@link android.widget.VideoView}.
* For ways of retrieving {@link Ringtone} objects or to show a ringtone
* picker, see {@link RingtoneManager}.
*
* @see RingtoneManager
*/
public class MediaPlayer implements SubtitleController.Listener{}4.demo
因为这个demo很简单，就一个Activity和xml，所以我就不提供源码下载了。
请直接看码：
package android.media;
package org.tuzhao.demo.activity;
import android.app.Activity;
import android.content.res.AssetFileDescriptor;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.media.Ringtone;
import android.media.RingtoneManager;
import android.media.SoundPool;
import android.net.Uri;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import org.tuzhao.sqlite.R;
import java.io.IOException;
/**
* three types to play sound
* @author tuzhao
*/
public class SoundActivity extends AppCompatActivity implements View.OnClickListener {
private Ringtone ringtone;
private SoundPool soundPool;
private int loadId;
private MediaPlayer mediaPlayer;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sound);
//初始化这三个方法
ringtone = initRingtone(this);
soundPool = initSoundPool();
loadId = soundPool.load(this, R.raw.beep, 1);
mediaPlayer = initMediaPlayer(this, 0);
findViewById(R.id.bt_ringtone).setOnClickListener(this);
findViewById(R.id.bt_sound_pool).setOnClickListener(this);
findViewById(R.id.bt_media).setOnClickListener(this);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.bt_ringtone:
ringtone.play();
break;
case R.id.bt_sound_pool:
soundPool.play(loadId, 1.0f, 1.0f, 0, 0, 1.0f);
break;
case R.id.bt_media:
mediaPlayer.start();
break;
}
}
@Override
protected void onDestroy() {
super.onDestroy();
//release resource of this two types.
soundPool.release();
mediaPlayer.release();
}
/**
* init type of Ringtone
* @param context Activity
* @return Ringtone
*/
private Ringtone initRingtone(Activity context) {
Uri notification = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
return RingtoneManager.getRingtone(context, notification);
}
/**
* init type of SoundPool
* @return SoundPool
*/
@SuppressWarnings("deprecation")
private SoundPool initSoundPool() {
// The content of the comments need API-23
// SoundPool.Builder builder=new SoundPool.Builder();
// builder.setMaxStreams(10);
//
// AudioAttributes.Builder audioBuilder=new AudioAttributes.Builder();
// audioBuilder.setContentType(AudioAttributes.CONTENT_TYPE_UNKNOWN);
// audioBuilder.setFlags(AudioAttributes.FLAG_AUDIBILITY_ENFORCED);
// audioBuilder.setLegacyStreamType(AudioManager.STREAM_SYSTEM);
// audioBuilder.setUsage(AudioAttributes.USAGE_NOTIFICATION);
// AudioAttributes attributes = audioBuilder.build();
//
// builder.setAudioAttributes(attributes);
// SoundPool soundPool = builder.build();
return new SoundPool(10, AudioManager.STREAM_NOTIFICATION, 5);
}
/**
* init type of MediaPlayer
* @param context Activity
* @param rawId the id of raw
* @return MediaPlayer
*/
public MediaPlayer initMediaPlayer(Activity context, int rawId) {
context.setVolumeControlStream(AudioManager.STREAM_MUSIC);
final MediaPlayer mediaPlayer = new MediaPlayer();
mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
/**
* When the beep has finished playing, rewind to queue up another one.
*/
mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mp) {
mediaPlayer.seekTo(0);
}
});
mediaPlayer.setOnErrorListener(new MediaPlayer.OnErrorListener() {
@Override
public boolean onError(MediaPlayer mp, int what, int extra) {
mediaPlayer.release();
return true;
}
});
AssetFileDescriptor file;
if (rawId == 0) {
file = context.getResources().openRawResourceFd(R.raw.beep);
} else {
file = context.getResources().openRawResourceFd(rawId);
}
try {
mediaPlayer.setDataSource(file.getFileDescriptor(),
file.getStartOffset(), file.getLength());
file.close();
float BEEP_VOLUME = 1.0f;
mediaPlayer.setVolume(BEEP_VOLUME, BEEP_VOLUME);
mediaPlayer.prepare();
} catch (IOException e) {
e.printStackTrace();
Log.i("initSpecifiedSound", "what happened to init sound? you need to deal it .");
return null;
}
return mediaPlayer;
}
}
下面是xml布局：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="org.tuzhao.sqlite.activity.SoundActivity">
<Button
android:id="@+id/bt_ringtone"
android:layout_width="120dp"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="88dp"
android:text="Ringtone"
android:textAllCaps="false"
/>
<Button
android:id="@+id/bt_sound_pool"
android:layout_width="120dp"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/bt_ringtone"
android:layout_alignStart="@+id/bt_ringtone"
android:layout_below="@+id/bt_ringtone"
android:layout_marginTop="15dp"
android:text="SoundPool"
android:textAllCaps="false"/>
<Button
android:id="@+id/bt_media"
android:layout_width="120dp"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/bt_sound_pool"
android:layout_alignStart="@+id/bt_sound_pool"
android:layout_below="@+id/bt_sound_pool"
android:layout_marginTop="15dp"
android:text="MediaPlayer"
android:textAllCaps="false"/>
</RelativeLayout>5.bug record
bugs：
AudioTrack: AudioFlinger could not create track, status: -12
AudioFlinger: no more track names available
AudioSink: Unable to create audio track
MediaPlayer: Should have subtitle controller already set
resolve：我出现这种情况是因为我最刚开始采用的不是上面Java文件初始化的方法，而是每播放一次声音就new 一个对象来播放声音。这样能播放，但是播放了十几次就报上面的错误。正确做法是只初始化一次。
每次调用下面这三个分别对应方法：
soundPool.play(sourceId, 1.0f, 1.0f, 0, 0, 1.0f);
ringtone.play();
mediaPlayer.start();
本人才疏学浅，出错在所难免。如文中有错误的地方望指正，谢谢！
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