使用服务、AsyncTask和线程开发智能安卓媒体播放器应用程序
使用服务、AsyncTask和线程开发智能安卓媒体播放器应用程序
提问于 2015-09-08 06:38:01
首先:如果我拼写错了，很抱歉。我来自巴拉圭，我正在使用谷歌翻译。
这可能有点傻，我是一个完美主义者，就像任何优秀的开发人员和设计师一样，我不想在我的项目中出现bug。我正在学习过程中，希望能和你一起学到很多东西。
我已经看到媒体播放器应用程序允许用户在不关闭应用程序的情况下快速和反复地按play/stop按钮，并且它仍然正常工作，所以我阅读了Services、AsyncTask和Thread。不仅要在后台播放声音，而且也不要用UI错误杀死我的应用程序。我还有很多问题要问。
我想知道使用以下资源(在网上找到)是否走上了一条好的道路，但当我多次按play/stop buttom或有时根本不播放歌曲时，应用程序就会死掉。
package com.myaudioservice.app;
import android.app.Service;
import android.content.Intent;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.os.AsyncTask;
import android.os.Binder;
import android.os.IBinder;
/**
* Service to serv MediaPlayer in background
*
* @author Eugeny Pozharsky
*/
public class PlayerService extends Service {
private final IBinder mBinder = new LocalBinder();
private MediaPlayer mediaPlayer;
private PlayerCallback callback;
public class LocalBinder extends Binder {
PlayerService getService() {
return PlayerService.this;
}
}
@Override
public IBinder onBind(Intent intent) {
return mBinder;
}
/**
* Kill MediaPlayer to release resources
*/
@Override
public void onDestroy() {
super.onDestroy();
if (mediaPlayer != null) {
stop();
mediaPlayer.release();
}
}
/**
* Starts playing stream.
* Note that we just start media player and do not obtain real URL of the stream.
* So, URL that will be redirected by server will not work. To make such URLs works, adding
* algorithm to obtain the real URL (f.e., create HttpConnection, connect to the server and
* get real URL from connection).
*
* @param url String with URL of a server to connect
*/
public void start(String url) {
if (mediaPlayer == null) {
mediaPlayer = new MediaPlayer();
}
if (isPlaying()) {
mediaPlayer.stop();
mediaPlayer.reset();
}
new Player().execute(url);
Log.e("PlayerService", "start()");
}
/**
* Stops playing of the stream.
*/
public void stop() {
// stopping MediaPlayer in separate thread because it can take a time
new Thread(new Runnable() {
@Override
public void run() {
if (mediaPlayer != null) {
if (mediaPlayer.isPlaying()) {
mediaPlayer.stop();
}
//mediaPlayer.release();
//mediaPlayer = null;
}
}
}).start();
if (callback != null) {
callback.onStopped();
}
Log.e("PlayerService", "stop()");
}
/**
* Is stream playing?
*
* @return true or false
*/
public Boolean isPlaying() {
return mediaPlayer != null && mediaPlayer.isPlaying();
}
public void setCallback(PlayerCallback callback) {
this.callback = callback;
}
/**
* Background task to start MediaPlayer. It is used because starting playing of remote stream may
* take long time and we must not block UI thread.
* Also, this approach allows to cancel starting process (not implemented in current version)
*/
private class Player extends AsyncTask<String, Void, Void> {
/**
* This function called in UI thread and we callback to activity to update UI elements
*/
@Override
protected void onPreExecute() {
super.onPreExecute();
if (callback != null) {
callback.onPreStart();
}
}
/**
* This function called in UI thread and we callback to activity to update UI elements
*/
@Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
if (mediaPlayer == null || !mediaPlayer.isPlaying()) {
// Start MediaPlayer fail.
if (callback != null) {
callback.onStartFailed();
}
} else {
if (callback != null) {
callback.onStarted();
}
}
}
/**
* This function called from separate thread and we do long-time operation in it
*
* @param strings params
* @return null
*/
@Override
protected Void doInBackground(String... strings) {
//mediaPlayer = new MediaPlayer();
try {
mediaPlayer.setDataSource(strings[0]);
mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
mediaPlayer.prepare();
mediaPlayer.start();
} catch (Exception e) {
if (mediaPlayer != null) {
mediaPlayer.release();
}
mediaPlayer = null;
}
return null;
}
}
}我想知道我是否应该在任何时候取消我的AsyncTask进程，或者我是否应该添加/修改应用程序不会死的东西。我该怎么办？有人能指引我吗？
我通常在日志广播中得到错误(如果出现的话)，如下所示：
java.lang.IllegalStateException: Cannot execute task: the task has already been executed (a task can be executed only once)播放/停止按钮：
btn_control.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
control((!ON_PLAY) ? 1 : 0);
}
});
private void control(int est) {
if(est==1){
if (!hayConexion()) {
Toast.makeText(Principal.this, getString(R.string.error_conexion_txt), Toast.LENGTH_SHORT).show();
} else {
if (mBound) {
mService.start();
ON_PLAY = true;
}
}
}else if(est==0) {
if (mBound) {
mService.stop();
ON_PLAY = false;
}
}
}编辑：
逻辑猫：
09-08 03:13:08.333 32438-32474/com.myaudioservice.app V/MediaPlayer-JNI﹕ native_setup
09-08 03:13:08.333 32438-32474/com.myaudioservice.app V/MediaPlayer﹕ constructor
09-08 03:13:08.343 32438-32474/com.myaudioservice.app V/MediaPlayer﹕ setListener
09-08 03:13:08.343 32438-32474/com.myaudioservice.app I/MediaPlayer﹕ path is null
09-08 03:13:08.343 32438-32474/com.myaudioservice.app D/MediaPlayer﹕ setDataSource IOException happend :
java.io.FileNotFoundException: No content provider: rtsp://ip/folder/file.stream
at android.content.ContentResolver.openTypedAssetFileDescriptor(ContentResolver.java:1053)
at android.content.ContentResolver.openAssetFileDescriptor(ContentResolver.java:907)
at android.content.ContentResolver.openAssetFileDescriptor(ContentResolver.java:834)
at android.media.MediaPlayer.setDataSource(MediaPlayer.java:988)
at android.media.MediaPlayer.setDataSource(MediaPlayer.java:942)
at com.myaudioservice.app.PlayerService$Player.doInBackground(PlayerService.java:156)
at com.myaudioservice.app.PlayerService$Player.doInBackground(PlayerService.java:130)
at android.os.AsyncTask$2.call(AsyncTask.java:288)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:841)
09-08 03:13:08.343 32438-32474/com.myaudioservice.app D/MediaPlayer﹕ Couldn't open file on client side, trying server side
09-08 03:13:08.353 32438-32474/com.myaudioservice.app V/MediaPlayer-JNI﹕ setAudioStreamType: 3
09-08 03:13:08.353 32438-32474/com.myaudioservice.app V/MediaPlayer﹕ MediaPlayer::setAudioStreamType
09-08 03:13:08.353 32438-32474/com.myaudioservice.app D/com.myaudioservice.app.PlayerService﹕ Preparing: rtsp://ip/folder/file.stream
09-08 03:13:08.353 32438-32474/com.myaudioservice.app V/MediaPlayer﹕ setVideoSurfaceTexture
09-08 03:13:08.353 32438-32474/com.myaudioservice.app V/MediaPlayer﹕ prepare
09-08 03:13:09.384 32438-32438/com.myaudioservice.app E/PlayerService﹕ stop()
09-08 03:13:09.394 32438-32495/com.myaudioservice.app V/MediaPlayer-JNI﹕ isPlaying: 0
09-08 03:13:09.394 32438-32495/com.myaudioservice.app V/MediaPlayer-JNI﹕ release
09-08 03:13:09.394 32438-32495/com.myaudioservice.app V/MediaPlayer﹕ setListener
09-08 03:13:09.394 32438-32495/com.myaudioservice.app V/MediaPlayer﹕ disconnect
09-08 03:13:09.544 32438-32438/com.myaudioservice.app D/AndroidRuntime﹕ Shutting down VM
09-08 03:13:09.544 32438-32438/com.myaudioservice.app W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x4193eda0)
09-08 03:13:09.544 32438-32438/com.myaudioservice.app E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.myaudioservice.app, PID: 32438
java.lang.IllegalStateException
at android.media.MediaPlayer.isPlaying(Native Method)
at com.myaudioservice.app.PlayerService.reproduciendo(PlayerService.java:118)
at com.myaudioservice.app.PlayerService.start(PlayerService.java:84)
at com.myaudioservice.app.MainActivity.control(MainActivity.java:298)
at com.myaudioservice.app.MainActivity.access$100(MainActivity.java:38)
at com.myaudioservice.app.MainActivity$1.onClick(MainActivity.java:173)
at android.view.View.performClick(View.java:4640)
at android.view.View$PerformClick.run(View.java:19425)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5593)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
at dalvik.system.NativeStart.main(Native Method)新LOGCAT:
09-08 14:49:24.360 9651-9651/com.myaudioservice.app V/MediaPlayer﹕ isPlaying: no active player
09-08 14:49:24.360 9651-9651/com.myaudioservice.app V/MediaPlayer-JNI﹕ isPlaying: 0
09-08 14:49:24.390 9651-9651/com.myaudioservice.app E/PlayerService﹕ start()
09-08 14:49:24.480 9651-10534/com.myaudioservice.app V/MediaPlayer﹕ isPlaying: no active player
09-08 14:49:24.480 9651-10534/com.myaudioservice.app V/MediaPlayer-JNI﹕ isPlaying: 0
09-08 14:49:24.480 9651-10534/com.myaudioservice.app V/MediaPlayer-JNI﹕ reset
09-08 14:49:24.480 9651-10534/com.myaudioservice.app V/MediaPlayer﹕ reset
09-08 14:49:24.490 9651-9651/com.myaudioservice.app E/PlayerService﹕ stop()
09-08 14:49:24.620 9651-9651/com.myaudioservice.app V/MediaPlayer﹕ isPlaying: no active player
09-08 14:49:24.620 9651-9651/com.myaudioservice.app V/MediaPlayer-JNI﹕ isPlaying: 0
09-08 14:49:24.650 9651-9651/com.myaudioservice.app E/PlayerService﹕ start()
09-08 14:49:24.770 9651-10535/com.myaudioservice.app V/MediaPlayer﹕ isPlaying: no active player
09-08 14:49:24.770 9651-10535/com.myaudioservice.app V/MediaPlayer-JNI﹕ isPlaying: 0
09-08 14:49:24.770 9651-10535/com.myaudioservice.app V/MediaPlayer-JNI﹕ reset
09-08 14:49:24.770 9651-10535/com.myaudioservice.app V/MediaPlayer﹕ reset
09-08 14:49:24.780 9651-9651/com.myaudioservice.app E/PlayerService﹕ stop()
09-08 14:49:24.890 9651-9651/com.myaudioservice.app V/MediaPlayer﹕ isPlaying: no active player
09-08 14:49:24.890 9651-9651/com.myaudioservice.app V/MediaPlayer-JNI﹕ isPlaying: 0
09-08 14:49:24.910 9651-9651/com.myaudioservice.app E/PlayerService﹕ start()
09-08 14:49:25.021 9651-10540/com.myaudioservice.app V/MediaPlayer﹕ isPlaying: no active player
09-08 14:49:25.031 9651-10540/com.myaudioservice.app V/MediaPlayer-JNI﹕ isPlaying: 0
09-08 14:49:25.031 9651-10540/com.myaudioservice.app V/MediaPlayer-JNI﹕ reset
09-08 14:49:25.031 9651-10540/com.myaudioservice.app V/MediaPlayer﹕ reset
09-08 14:49:25.041 9651-9651/com.myaudioservice.app E/PlayerService﹕ stop()
09-08 14:49:25.151 9651-9651/com.myaudioservice.app V/MediaPlayer﹕ isPlaying: no active player
09-08 14:49:25.151 9651-9651/com.myaudioservice.app V/MediaPlayer-JNI﹕ isPlaying: 0
09-08 14:49:25.181 9651-9651/com.myaudioservice.app E/PlayerService﹕ start()-----------------------------------------------------------------------编辑2：
我以为我已经有了它，直到我发现了一个bug (就在我的服务结束时)：
编辑的PlayerService类
package com.myaudioservice.app;
import android.app.Service;
import android.content.Intent;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;
public class PlayerService extends Service implements MediaPlayer.OnPreparedListener, MediaPlayer.OnInfoListener, MediaPlayer.OnCompletionListener {
private static final String LOG_TAG = PlayerService.class.getName();
private String URL_STREAM = "rtsp://domain/folder/file.stream";
private MediaPlayer mMediaPlayer = null;
private PlayerCallback callback;
private final IBinder mBinder = new LocalBinder();
public class LocalBinder extends Binder {
PlayerService getService() {
return PlayerService.this;
}
}
@Override
public IBinder onBind(Intent intent) {
return mBinder;
}
@Override
public void onDestroy(){
if (mMediaPlayer != null) {
stop();
mMediaPlayer.release();
mMediaPlayer = null;
}
}
/**
* Starts playing stream.
* Note that we just start media player and do not obtain real URL of the stream.
* So, URL that will be redirected by server will not work. To make such URLs works, adding
* algorithm to obtain the real URL (f.e., create HttpConnection, connect to the server and
* get real URL from connection).
*
* //@param url String with URL of a server to connect
*/
public void start() {
if (mMediaPlayer == null) mMediaPlayer = new MediaPlayer();
if (isPlaying()) {
mMediaPlayer.stop();
mMediaPlayer.reset();
}
try {
mMediaPlayer.setDataSource(URL_STREAM);
mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
if (callback != null) callback.onPreStart();
Log.e(LOG_TAG, "Preparando: " + URL_STREAM);
mMediaPlayer.prepareAsync();
} catch (Exception e) {
if (mMediaPlayer != null) {
mMediaPlayer.reset();
}
Log.e(LOG_TAG, e.toString());
//mMediaPlayer = null;
}
mMediaPlayer.setOnPreparedListener(this);
mMediaPlayer.setOnInfoListener(this);
mMediaPlayer.setOnCompletionListener(this);
}
@Override
public void onPrepared(MediaPlayer mp) {
mp.start();
Log.e(LOG_TAG, "start()");
}
@Override
public boolean onInfo(MediaPlayer mp, int what, int extra) {
switch (what) {
case MediaPlayer.MEDIA_ERROR_IO:
case MediaPlayer.MEDIA_ERROR_MALFORMED:
case MediaPlayer.MEDIA_ERROR_NOT_VALID_FOR_PROGRESSIVE_PLAYBACK:
case MediaPlayer.MEDIA_ERROR_SERVER_DIED:
case MediaPlayer.MEDIA_ERROR_TIMED_OUT:
case MediaPlayer.MEDIA_ERROR_UNSUPPORTED:
if (mMediaPlayer == null || !mMediaPlayer.isPlaying()) {
// Start MediaPlayer fail.
if (callback != null) callback.onStartFailed();
}
Log.e(LOG_TAG, "Error");
break;
case MediaPlayer.MEDIA_INFO_BUFFERING_START:
if (callback != null) callback.onStarted();
Log.e(LOG_TAG, "Almacenando en búfer");
break;
case MediaPlayer.MEDIA_INFO_BUFFERING_END:
if (callback != null) callback.onPlaying();
Log.e(LOG_TAG, "Reproduciendo");
break;
}
return false;
}
@Override
public void onCompletion(MediaPlayer mp) {
Log.e(LOG_TAG, "Reproducción finalizada");
stop();
}
/**
* Stops playing of the stream.
*/
public void stop() {
// stopping MediaPlayer in separate thread because it can take a time
new Thread(new Runnable() {
@Override
public void run() {
if (mMediaPlayer != null) {
if (mMediaPlayer.isPlaying()) mMediaPlayer.stop(); // I get the error here when I destroy the Service quickly
mMediaPlayer.reset();
}
}
}).start();
if (callback != null) callback.onStopped();
Log.e(LOG_TAG, "stop()");
}
/**
* Is stream playing?
*
* @return true or false
*/
public Boolean isPlaying() {
return mMediaPlayer != null && mMediaPlayer.isPlaying();
}
public void setCallback(PlayerCallback callback) {
this.callback = callback;
}
}逻辑猫：
09-08 19:15:39.578 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ isPlaying: no active player
09-08 19:15:39.578 27582-27582/com.myaudioservice.app V/MediaPlayer-JNI﹕ isPlaying: 0
09-08 19:15:39.578 27582-27582/com.myaudioservice.app V/MediaPlayer-JNI﹕ setAudioStreamType: 3
09-08 19:15:39.578 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ MediaPlayer::setAudioStreamType
09-08 19:15:39.578 27582-27582/com.myaudioservice.app E/com.myaudioservice.app.PlayerService﹕ Preparando: rtsp://domain/folder/file.stream
09-08 19:15:39.578 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ setVideoSurfaceTexture
09-08 19:15:39.578 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ prepareAsync
09-08 19:15:39.678 27582-31945/com.myaudioservice.app V/MediaPlayer-JNI﹕ isPlaying: 0
09-08 19:15:39.678 27582-31945/com.myaudioservice.app V/MediaPlayer-JNI﹕ reset
09-08 19:15:39.678 27582-31945/com.myaudioservice.app V/MediaPlayer﹕ reset
09-08 19:15:39.678 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ message received msg=1, ext1=0, ext2=0
09-08 19:15:39.688 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ notify(1, 0, 0) callback on disconnected mediaplayer
09-08 19:15:39.688 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ message received msg=8, ext1=0, ext2=0
09-08 19:15:39.688 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ notify(8, 0, 0) callback on disconnected mediaplayer
09-08 19:15:39.688 27582-27582/com.myaudioservice.app E/com.myaudioservice.app.PlayerService﹕ stop()
09-08 19:15:39.798 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ isPlaying: no active player
09-08 19:15:39.798 27582-27582/com.myaudioservice.app V/MediaPlayer-JNI﹕ isPlaying: 0
09-08 19:15:39.808 27582-27582/com.myaudioservice.app V/MediaPlayer-JNI﹕ setAudioStreamType: 3
09-08 19:15:39.808 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ MediaPlayer::setAudioStreamType
09-08 19:15:39.808 27582-27582/com.myaudioservice.app E/com.myaudioservice.app.PlayerService﹕ Preparando: rtsp://domain/folder/file.stream
09-08 19:15:39.808 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ setVideoSurfaceTexture
09-08 19:15:39.808 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ prepareAsync
09-08 19:15:39.938 27582-31952/com.myaudioservice.app V/MediaPlayer-JNI﹕ isPlaying: 0
09-08 19:15:39.938 27582-31952/com.myaudioservice.app V/MediaPlayer-JNI﹕ reset
09-08 19:15:39.938 27582-31952/com.myaudioservice.app V/MediaPlayer﹕ reset
09-08 19:15:39.938 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ message received msg=1, ext1=0, ext2=0
09-08 19:15:39.938 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ notify(1, 0, 0) callback on disconnected mediaplayer
09-08 19:15:39.938 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ message received msg=8, ext1=0, ext2=0
09-08 19:15:39.938 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ notify(8, 0, 0) callback on disconnected mediaplayer
09-08 19:15:39.948 27582-27582/com.myaudioservice.app E/com.myaudioservice.app.PlayerService﹕ stop()
09-08 19:15:40.069 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ isPlaying: no active player
09-08 19:15:40.069 27582-27582/com.myaudioservice.app V/MediaPlayer-JNI﹕ isPlaying: 0
09-08 19:15:40.079 27582-27582/com.myaudioservice.app V/MediaPlayer-JNI﹕ setAudioStreamType: 3
09-08 19:15:40.079 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ MediaPlayer::setAudioStreamType
09-08 19:15:40.079 27582-27582/com.myaudioservice.app E/com.myaudioservice.app.PlayerService﹕ Preparando: rtsp://domain/folder/file.stream
09-08 19:15:40.079 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ setVideoSurfaceTexture
09-08 19:15:40.079 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ prepareAsync
09-08 19:15:40.179 27582-31957/com.myaudioservice.app V/MediaPlayer-JNI﹕ isPlaying: 0
09-08 19:15:40.179 27582-31957/com.myaudioservice.app V/MediaPlayer-JNI﹕ reset
09-08 19:15:40.179 27582-31957/com.myaudioservice.app V/MediaPlayer﹕ reset
09-08 19:15:40.179 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ message received msg=1, ext1=0, ext2=0
09-08 19:15:40.189 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ notify(1, 0, 0) callback on disconnected mediaplayer
09-08 19:15:40.189 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ message received msg=8, ext1=0, ext2=0
09-08 19:15:40.189 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ notify(8, 0, 0) callback on disconnected mediaplayer
09-08 19:15:40.189 27582-27582/com.myaudioservice.app E/com.myaudioservice.app.PlayerService﹕ stop()
09-08 19:15:40.289 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ isPlaying: no active player
09-08 19:15:40.289 27582-27582/com.myaudioservice.app V/MediaPlayer-JNI﹕ isPlaying: 0
09-08 19:15:40.299 27582-27582/com.myaudioservice.app V/MediaPlayer-JNI﹕ setAudioStreamType: 3
09-08 19:15:40.299 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ MediaPlayer::setAudioStreamType
09-08 19:15:40.299 27582-27582/com.myaudioservice.app E/com.myaudioservice.app.PlayerService﹕ Preparando: rtsp://domain/folder/file.stream
09-08 19:15:40.299 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ setVideoSurfaceTexture
09-08 19:15:40.299 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ prepareAsync
09-08 19:15:40.429 27582-31966/com.myaudioservice.app V/MediaPlayer-JNI﹕ isPlaying: 0
09-08 19:15:40.429 27582-31966/com.myaudioservice.app V/MediaPlayer-JNI﹕ reset
09-08 19:15:40.429 27582-31966/com.myaudioservice.app V/MediaPlayer﹕ reset
09-08 19:15:40.429 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ message received msg=1, ext1=0, ext2=0
09-08 19:15:40.429 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ notify(1, 0, 0) callback on disconnected mediaplayer
09-08 19:15:40.429 27582-27582/com.myaudioservice.app E/com.myaudioservice.app.PlayerService﹕ stop()
09-08 19:15:40.429 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ message received msg=8, ext1=0, ext2=0
09-08 19:15:40.429 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ notify(8, 0, 0) callback on disconnected mediaplayer
09-08 19:15:40.549 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ isPlaying: no active player
09-08 19:15:40.549 27582-27582/com.myaudioservice.app V/MediaPlayer-JNI﹕ isPlaying: 0
09-08 19:15:40.559 27582-27582/com.myaudioservice.app V/MediaPlayer-JNI﹕ setAudioStreamType: 3
09-08 19:15:40.559 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ MediaPlayer::setAudioStreamType
09-08 19:15:40.559 27582-27582/com.myaudioservice.app E/com.myaudioservice.app.PlayerService﹕ Preparando: rtsp://domain/folder/file.stream
09-08 19:15:40.559 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ setVideoSurfaceTexture
09-08 19:15:40.559 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ prepareAsync
09-08 19:15:40.659 27582-31972/com.myaudioservice.app V/MediaPlayer-JNI﹕ isPlaying: 0
09-08 19:15:40.659 27582-31972/com.myaudioservice.app V/MediaPlayer-JNI﹕ reset
09-08 19:15:40.659 27582-31972/com.myaudioservice.app V/MediaPlayer﹕ reset
09-08 19:15:40.659 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ message received msg=1, ext1=0, ext2=0
09-08 19:15:40.659 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ notify(1, 0, 0) callback on disconnected mediaplayer
09-08 19:15:40.659 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ message received msg=8, ext1=0, ext2=0
09-08 19:15:40.659 27582-27596/com.myaudioservice.app V/MediaPlayer﹕ notify(8, 0, 0) callback on disconnected mediaplayer
09-08 19:15:40.669 27582-27582/com.myaudioservice.app E/com.myaudioservice.app.PlayerService﹕ stop()
09-08 19:16:01.281 27582-27582/com.myaudioservice.app D/AbsListView﹕ onDetachedFromWindow
09-08 19:16:01.311 27582-27582/com.myaudioservice.app E/com.myaudioservice.app.PlayerService﹕ stop()
09-08 19:16:01.311 27582-27582/com.myaudioservice.app V/MediaPlayer-JNI﹕ release
09-08 19:16:01.311 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ setListener
09-08 19:16:01.311 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ disconnect
09-08 19:16:01.311 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ destructor
09-08 19:16:01.311 27582-32148/com.myaudioservice.app W/dalvikvm﹕ threadid=14: thread exiting with uncaught exception (group=0x4193eda0)
09-08 19:16:01.311 27582-27582/com.myaudioservice.app V/MediaPlayer﹕ disconnect
09-08 19:16:01.321 27582-32148/com.myaudioservice.app E/AndroidRuntime﹕ FATAL EXCEPTION: Thread-15992
Process: com.myaudioservice.app, PID: 27582
java.lang.IllegalStateException
at android.media.MediaPlayer.isPlaying(Native Method)
at com.myaudioservice.app.PlayerService$1.run(PlayerService.java:129)
at java.lang.Thread.run(Thread.java:841)回答 2
Stack Overflow用户
发布于 2015-09-08 11:38:08
在文档中，如果内部播放器引擎尚未初始化或已释放，则可以读取MediaPlayer.isPlaying()抛出IllegalStateException。
这段代码不是线程安全的，这可能是这个异常的原因(线程调用release()，在mediaPlayer设置为null应用程序调用发布的mediaPlayer上的isPlaying()之前)。您需要添加一些同步来使其工作(或使用异步方法形式的MediaPlayer)。
Stack Overflow用户
发布于 2015-09-09 01:59:58
好吧，我想我终于得到我想要的了。我不知道是否应该将@KamilW响应标记为正确的，因为它确实是完全正确的，但是我将用正确的代码(或者至少认为是正确的)回答我的问题，它可能对其他人有用。
我的最后代码：
package com.myaudioservice.app;
import android.app.Service;
import android.content.Intent;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;
public class PlayerService extends Service implements MediaPlayer.OnPreparedListener, MediaPlayer.OnInfoListener, MediaPlayer.OnErrorListener, MediaPlayer.OnCompletionListener {
private static final String LOG_TAG = PlayerService.class.getName();
private String URL_STREAM = "rtsp://domain/folder/file.stream";
private MediaPlayer mMediaPlayer = null;
private PlayerCallback callback;
private final IBinder mBinder = new LocalBinder();
public class LocalBinder extends Binder {
PlayerService getService() {
return PlayerService.this;
}
}
@Override
public IBinder onBind(Intent intent) {
return mBinder;
}
@Override
public void onDestroy(){
if (mMediaPlayer != null) {
mMediaPlayer.release();
mMediaPlayer = null;
}
}
/**
* Starts playing stream.
* Note that we just start media player and do not obtain real URL of the stream.
* So, URL that will be redirected by server will not work. To make such URLs works, adding
* algorithm to obtain the real URL (f.e., create HttpConnection, connect to the server and
* get real URL from connection).
*
* //@param url String with URL of a server to connect
*/
public void start() {
if (mMediaPlayer == null) mMediaPlayer = new MediaPlayer();
if (isPlaying()) {
mMediaPlayer.stop();
mMediaPlayer.reset();
}
try {
mMediaPlayer.setDataSource(URL_STREAM);
mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
if (callback != null) callback.onPreStart();
Log.e(LOG_TAG, "Preparando: " + URL_STREAM);
mMediaPlayer.prepareAsync();
} catch (Exception e) {
if (mMediaPlayer != null) {
mMediaPlayer.reset();
}
if (callback != null) callback.onStartFailed();
Log.e(LOG_TAG, e.toString());
//mMediaPlayer = null;
}
mMediaPlayer.setOnPreparedListener(this);
mMediaPlayer.setOnInfoListener(this);
mMediaPlayer.setOnErrorListener(this);
mMediaPlayer.setOnCompletionListener(this);
}
@Override
public void onPrepared(MediaPlayer mp) {
mp.start();
Log.e(LOG_TAG, "start()");
}
@Override
public boolean onInfo(MediaPlayer mp, int what, int extra) {
switch (what) {
case MediaPlayer.MEDIA_INFO_BUFFERING_START:
if (callback != null) callback.onStarted();
Log.e(LOG_TAG, "Almacenando en búfer");
break;
case MediaPlayer.MEDIA_INFO_BUFFERING_END:
if (callback != null) callback.onPlaying();
Log.e(LOG_TAG, "Reproduciendo");
break;
}
return false;
}
@Override
public void onCompletion(MediaPlayer mp) {
Log.e(LOG_TAG, "Reproducción finalizada");
stop();
}
/**
* Stops playing of the stream.
*/
public void stop() {
// stopping MediaPlayer in separate thread because it can take a time
new Thread(new Runnable() {
@Override
public void run() {
if (mMediaPlayer != null) {
if (mMediaPlayer.isPlaying()) mMediaPlayer.stop();
mMediaPlayer.reset();
}
}
}).start();
if (callback != null) callback.onStopped();
Log.e(LOG_TAG, "stop()");
}
/**
* Is stream playing?
*
* @return true or false
*/
public Boolean isPlaying() {
return mMediaPlayer != null && mMediaPlayer.isPlaying();
}
public void setCallback(PlayerCallback callback) {
this.callback = callback;
}
@Override
public boolean onError(MediaPlayer mp, int what, int extra){
if(what == MediaPlayer.MEDIA_ERROR_UNKNOWN ||
what == MediaPlayer.MEDIA_ERROR_SERVER_DIED ||
extra == MediaPlayer.MEDIA_ERROR_IO ||
extra == MediaPlayer.MEDIA_ERROR_MALFORMED ||
extra == MediaPlayer.MEDIA_ERROR_UNSUPPORTED ||
extra == MediaPlayer.MEDIA_ERROR_TIMED_OUT ||
extra == MediaPlayer.MEDIA_ERROR_NOT_VALID_FOR_PROGRESSIVE_PLAYBACK){
stop();
if (callback != null) callback.onStartFailed();
}
return true;// Si hay error, no es necesario llamar a onCompletionListener, por eso: true
}
}我也想被专家检查，告诉我在代码中需要改进什么(如果不要求太多的话)。打给你。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/32450826
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