本文将为您提供关于AndroidMediaPlayer.reset()正在调用onCompletion的详细介绍，我们还将为您解释正在启动android的相关知识，同时，我们还将为您提供关于(Andr
本文将为您提供关于Android MediaPlayer.reset()正在调用onCompletion的详细介绍，我们还将为您解释正在启动android的相关知识，同时，我们还将为您提供关于(Android MediaPlayer)如果MediaPlayer.create()隐式调用prepare(),我应该如何调用setAudioStreamType()？、Android MediaPlaye.getDuration()获取音视频时长的方式、Android Mediaplayer MediaController超时、android MediaPlayer NullPointerException的实用信息。
本文目录一览：- Android MediaPlayer.reset()正在调用onCompletion（正在启动android）
- (Android MediaPlayer)如果MediaPlayer.create()隐式调用prepare(),我应该如何调用setAudioStreamType()？
- Android MediaPlaye.getDuration()获取音视频时长的方式
- Android Mediaplayer MediaController超时
- android MediaPlayer NullPointerException
Android MediaPlayer.reset()正在调用onCompletion（正在启动android）
我遇到以下代码的问题.我在MediaController上调用了setPrevNextListener,并为Prev和Next定义了两个onClickListener.当我单击下一个按钮而不是前进一个轨道时,我前进两个轨道.这似乎是由于onCompletion被某种方式调用的事实. MediaPlayer.reset()是否会调用onCompletion？我已经包含了logcat输出和我的代码.如果我做错了,请告诉我.提前致谢.
logcat的：
02-24 00:36:34.826: D/MP(6675): Next Button Clicked,index was: 0 02-24 00:36:34.837: D/MP(6675): About to call Reset() 02-24 00:36:34.906: D/MP(6675): Inside setUpPlayer 02-24 00:36:34.917: D/MP(6675): Called setDataSource with index: 1 02-24 00:36:34.917: D/MP(6675): Leaving setUpPlayer 02-24 00:36:34.917: D/MP(6675): About to call prepareAsync() 02-24 00:36:34.937: D/MP(6675): Leaving next button 02-24 00:36:35.226: E/MediaPlayer(6675): Attempt to call getDuration without a valid mediaplayer 02-24 00:36:35.226: E/MediaPlayer(6675): error (-38,0) 02-24 00:36:35.276: E/MediaPlayer(6675): Error (-38,0) 02-24 00:36:35.287: D/MP(6675): Inside onCompletion 02-24 00:36:35.337: D/MP(6675): About to call Reset() 02-24 00:36:35.347: D/MP(6675): Inside setUpPlayer 02-24 00:36:35.356: D/MP(6675): Called setDataSource with index: 2 02-24 00:36:35.356: D/MP(6675): Leaving setUpPlayer 02-24 00:36:35.356: D/MP(6675): About to call prepareAsync() 02-24 00:36:35.377: D/MP(6675): Leaving onCompletion 02-24 00:36:36.517: D/MP(6675): Inside onPrepared,index is: 2 02-24 00:36:36.577: D/MP(6675): Leaving onPrepared
码：
public class MusicPlayerActivity extends Activity implements OnPreparedListener,OnCompletionListener,MediaController.MediaPlayerControl {
private MediaPlayer mp;
private MediaController mc;
private SonarDatabase db;
private SubsonicAPIConnector sonic;
ArrayList<String> songs;
int index = 0;
private Handler handler = new Handler();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.music_player);
// Get params from intent
Intent i = getIntent();
String albumId = i.getStringExtra("albumId");
String artistId = i.getStringExtra("artistId");
String albumName = i.getStringExtra("albumName");
String songName = i.getStringExtra("songName");
String songId = i.getStringExtra("songId");
String coverArt = "al-"+albumId+".jpeg";
String duration = i.getStringExtra("duration");
Log.d("MP","results: albumName:" + albumName + ",songName: " + songName + ",songId: "
+ songId + ",duration: " + duration + ",coverArt: " + coverArt + ",artistId: "
+ artistId + ",albumId: " + albumId);
db = new SonarDatabase(getApplicationContext());
sonic = new SubsonicAPIConnector(db.getURL(),db.getUsername(),db.getpassword());
String artistName = db.getArtistNameById(artistId);
setTitle("Now Playing");
songs = db.getSongListForAlbum(albumId);
index = songs.indexOf(songId);
Log.d("MP","songid: " + songId + ",index: " + index);
// Update text views with song information
TextView txtArtist = (TextView) findViewById(R.id.txtArtistName);
txtArtist.setText(artistName);
TextView txtAlbum = (TextView) findViewById(R.id.txtAlbumName);
txtAlbum.setText(albumName);
TextView txtSong = (TextView) findViewById(R.id.txtSongName);
txtSong.setText(songName);
// Show the album art
File img = new File(this.getFilesDir()+"/covers/"+coverArt);
if(img.exists()) {
Log.d("MP","Found image at: " + img.toString());
ImageView imgView = (ImageView) findViewById(R.id.cover_art);
imgView.se@R_301_5026@Bitmap(BitmapFactory.decodeFile(img.getPath()));
} else {
Log.d("MP","Couldn't find image: " + img.toString());
}
// Create the media player and controller
mp = new MediaPlayer();
mp.setonPreparedListener(this);
mp.setonCompletionListener(this);
mc = new NonHidingMediaController(this);
mc.setPrevNextListeners(new View.OnClickListener() {
@Override
public void onClick(View v) {
// next button clicked
Log.d("MP","Next Button Clicked,index was: " + index);
playNextTrack();
Log.d("MP","Leaving next button");
}
},new View.OnClickListener() {
@Override
public void onClick(View v) {
// prevIoUs button clicked
Log.d("MP","PrevIoUs button clicked,index was: " + index);
if(mp.isPlaying() && mp.getCurrentPosition() < 2000 && index != 0) {
Log.d("MP","Start the prior song.");
playPrevIoUsTrack();
} else {
Log.d("MP","Restart this song.");
restartCurrentTrack();
}
Log.d("MP","Leaving prevIoUs button");
}
});
mc.setMediaPlayer(this);
setUpPlayer();
Log.d("MP","About to call prepareAsync()");
mp.prepareAsync();
}
@Override
public void onCompletion(MediaPlayer mp) {
Log.d("MP","Inside onCompletion");
//Todo add code for scrobbling here.
playNextTrack();
Log.d("MP","Leaving onCompletion");
}
private void playNextTrack() {
index++;
TextView txtSong = (TextView) findViewById(R.id.txtSongName);
txtSong.setText(db.getSongNameById(songs.get(index)));
Log.d("MP","About to call Reset()");
mp.reset();
setUpPlayer();
Log.d("MP","About to call prepareAsync()");
mp.prepareAsync();
}
private void playPrevIoUsTrack() {
index--;
TextView txtSong = (TextView) findViewById(R.id.txtSongName);
txtSong.setText(db.getSongNameById(songs.get(index)));
Log.d("MP","About to call prepareAsync()");
mp.prepareAsync();
}
private void restartCurrentTrack() {
mp.seekTo(0);
}
public void onPrepared(MediaPlayer mp) {
Log.d("MP","Inside onPrepared,index is: " + index);
mc.setMediaPlayer(this);
mc.setAnchorView(findViewById(R.id.music_player_view));
mp.start();
handler.post(new Runnable() {
public void run() {
mc.setEnabled(true);
mc.show();
}
});
Log.d("MP","Leaving onPrepared");
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_music_player,menu);
return true;
}
@Override
public boolean onTouchEvent(MotionEvent event) {
Log.d("MP","OnTouchEvent called");
mc.show();
return false;
}
private void setUpPlayer() {
Log.d("MP","Inside setUpPlayer");
mp.setAudioStreamType(AudioManager.STREAM_MUSIC);
try {
mp.setDataSource(sonic.streamString("&id=" + songs.get(index)));
Log.d("MP","Called setDataSource with index: " + index);
} catch (IllegalArgumentException e) {
// Todo Auto-generated catch block
e.printstacktrace();
} catch (SecurityException e) {
// Todo Auto-generated catch block
e.printstacktrace();
} catch (IllegalStateException e) {
// Todo Auto-generated catch block
e.printstacktrace();
} catch (IOException e) {
// Todo Auto-generated catch block
e.printstacktrace();
}
Log.d("MP","Leaving setUpPlayer");
}
@Override
protected void onStop() {
super.onStop();
mc.hide();
mp.stop();
mp.release();
}
public void start() {
mp.start();
}
public void pause() {
mp.pause();
}
public int getDuration() {
return mp.getDuration();
}
public int getCurrentPosition() {
return mp.getCurrentPosition();
}
public void seekTo(int i) {
mp.seekTo(i);
}
public boolean isPlaying() {
return mp.isPlaying();
}
public int getBufferPercentage() {
return 0;
}
public boolean canPause() {
return true;
}
public boolean canSeekBackward() {
return true;
}
public boolean canSeekForward() {
return true;
}
public class NonHidingMediaController extends MediaController {
public NonHidingMediaController(Context context,AttributeSet attrs) {
super(context,attrs);
}
public NonHidingMediaController(Context context,boolean useFastForward) {
super(context,useFastForward);
}
public NonHidingMediaController(Context context) {
super(context);
}
@Override
public void show(int timeout) {
super.show(0);
}
}
}
解决方法
我对android源码进行了一些挖掘,发现任何未处理的错误都会导致MediaPlayer调用onCompletion处理程序.在这种情况下,您似乎在空闲,初始化或错误状态下调用getDuration.可以从媒体控制器内部进行.我建议在调用getDuration的任何地方之前添加一些Log.d(),以查看导致问题的调用的位置.
(Android MediaPlayer)如果MediaPlayer.create()隐式调用prepare(),我应该如何调用setAudioStreamType()？
我正在编写一个使用服务的
Android闹钟应用程序来播放闹钟.目前,我可以获得播放的音频,但播放的形式可以通过关闭设备的音量进行静音.因此,我试图添加一个调用setAudioStreamType(AudioManager.STREAM_ALARM);以防止这种情况.
我为我的onStartCommand()函数提供以下服务：
MediaPlayer mMP;
@Override
public int onStartCommand(Intent intent,int flags,int startId)
{
try
{
mMP = MediaPlayer.create(this,R.raw.alarm);
mMP.setAudioStreamType(AudioManager.STREAM_ALARM);
mMP.setLooping(true);
//mMP.prepare(); commented out since prepare() is called in create
}
catch (Exception e)
{
e.printstacktrace();
}
if (mMP != null) mMP.start();
return START_STICKY;
}
我的问题是,通过调用setAudioStreamType(),MediaPlayer从不播放音频.如果我评论该行,音频播放.
有了行,我得到以下运行时错误：
04-10 19:32:03.115: E/MediaPlayer(3411): setAudioStream called in state 8
04-10 19:32:03.115: E/MediaPlayer(3411): error (-38,0)
04-10 19:32:03.115: E/MediaPlayer(3411): start called in state 0
04-10 19:32:03.115: E/MediaPlayer(3411): error (-38,0)
04-10 19:32:03.115: E/MediaPlayer(3411): Error (-38,0)
有些研究(现在我找不到链接)告诉我,在调用prepare()之后,setAudioStreamType()不能被调用,而create()隐含地调用prepare().
在任何方面,我应该如何设置AudioStreamType()没有这样的错误？
解决方法
您可以调用mp.reset(),然后设置流类型,数据源,然后准备.或者,只需使用默认构造函数并自己处理初始化.
编辑：
Resources res = getResources(); AssetFileDescriptor afd = res.openRawResourceFd(R.raw.alarm); mp.reset(); mp.setAudioStreamType(AudioManager.STREAM_ALARM); mp.setLooping(true); mp.setDataSource(afd.getFileDescriptor(),afd.getStartOffset(),afd.getLength()); mp.prepare(); mp.start();
Android MediaPlaye.getDuration()获取音视频时长的方式
android MediaPlaye.getDuration()获取不到在线音乐时长,看看mediaPlayer.getDuration()的源码，里面明确地说了，不支持在线内容，所以，根本原因就是它（不过我本地资源也获取不到）
/**
* Gets the duration of the file.
*
* @return the duration in milliseconds,if no duration is available
* (for example,if streaming live content),-1 is returned.
*/
public native int getDuration();
解决办法：使用MediaMetadataRetriever获取音视频总时长。
try {
//1，创建MediaMetadataRetriever对象
MediaMetadataRetriever retriever = new MediaMetadataRetriever();
//2.设置音视频资源路径
retriever.setDataSource(path);
//3.获取音视频资源总时长
String time = retriever.extractMetadata(MediaMetadataRetriever.MetaDATA_KEY_DURATION);
}catch (Exception e){
e.printstacktrace();
}
遇到的问题：
报错：java.lang.RuntimeException: setDataSource Failed: status = 0x80000000
解决办法：
1.加网络权限
<uses-permission android:name=@H_301_115@"android.permission.INTERNET" />
2.替换下setDataSource的参数形式
FileInputStream inputStream = null;
try {
inputStream = new FileInputStream(new File(currentAudioPath).getAbsolutePath());
retriever.setDataSource(inputStream.getFD());
} catch (Exception e) {
e.printstacktrace();
}
String time = retriever.extractMetadata(MediaMetadataRetriever.MetaDATA_KEY_DURATION);
3.场景：使用MediaRecorder录制短视频，结束录后，马上通过path获取短视频的时长。这样也会导致报错；
原因：在MediaRecorder.release() 之前调用了获取时长的方法。
解释：MediaRecorder.release()没有调用前，视频文件还属于不完整状态。
解决方案：在MediaRecorder.release()结束后在调用获取时长的方法。
但是，通过这种方法获取的duration可能不准确，对于VBR格式的mp3，duration可能远远比真实的长度小。对于这个问题，可以用比特率和文件大小来计算：
下面是我采用的方式
MediaMetadataRetriever retriever = new MediaMetadataRetriever();
long fileSize = new File(currentAudioPath).length();
retriever.setDataSource(new File(currentAudioPath).getAbsolutePath());
long bitRate = Long.parseLong(retriever.extractMetadata(MediaMetadataRetriever.MetaDATA_KEY_BITRATE));
long duration = (fileSize*8) /(bitRate);//单位秒
retriever.release();//务必release
Android Mediaplayer MediaController超时
香港专业教育学院实现了流媒体的MP3 URL的mediaplayer和mediacontroller.但是,我在TMobile网络上的设备无法获得很好的3G信号,因此可以在EDGE上运行.我假设媒体播放器因流太慢或不完整而崩溃,是否可以设置超时？
解决方法:
MediaPlayer中没有超时方法,但是您可以自己实现-有多种方法可以执行.
我建议其中之一,我用了自己,对我有用-broadcastReceiver
代码如下所示：
public class ConnectivityCheckingReceiver extends WakefulbroadcastReceiver
{
private AlarmManager alarmManager;
private PendingIntent pendingIntent;
@Override
public void onReceive(Context context, Intent intent)
{
if (MusicService.mediaPlayer != null)
{
if (!MusicService.mediaPlayer.isPlaying())
Log.v("Music", "Music is NOT playing");
//stop service and notify user
else
Log.v("Music", "Music is playing");
}
else
{
Log.v("Music", "User stopped player");
}
}
public void setAlarm (Context context, int hour, int minute, int second)
{
alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(context, ConnectivityCheckingReceiver.class);
pendingIntent = PendingIntent.getbroadcast(context, 0, intent, 0);
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, hour);
calendar.set(Calendar.MINUTE, minute);
calendar.set(Calendar.SECOND, second);
alarmManager.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);
}
}
在活动/服务/片段中添加以下行：
ConnectivityCheckingReceiver conCheck = new ConnectivityCheckingReceiver();
conCheck.setAlarm(context, hour, min, second);
您将需要自己实现小时/分钟/秒检查逻辑,但是使用Joda Time之类的库就可以轻松实现.
并且不要忘记添加到清单中：
<uses-permission android:name="android.permission.WAKE_LOCK" />
<receiver android:name=".receivers.ConnectivityCheckingReceiver" />
附言：我的解决方案不是完美的,但是我没有看到关于此问题的任何好答案,因此,如果找到一个,请分享.
android MediaPlayer NullPointerException
我有点难以对此进行故障排除,因为我是通过其他人的
Android设备的崩溃报告得到的,我无法向他们提问,而且我从未在自己的Android设备上看到它.
崩溃报告说它是Android 4.1.2,堆栈跟踪是：
java.lang.NullPointerException at android.media.MediaPlayer$EventHandler.handleMessage(MediaPlayer.java:2102) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:137) at android.app.ActivityThread.main(ActivityThread.java:5021) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:511) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:556) at dalvik.system.NativeStart.main(Native Method)
不幸的是,grepcode.com上的android源代码似乎与这些行号不匹配,所以我不确定哪个是null.
当发生这种情况时,我不知道用户正在做什么,所以我不知道这是在音乐或声音效果正在播放时发生,还是在发生破坏时发生了什么.我有点怀疑它可能在毁灭期间发生.我在activity的onDestroy方法中有以下代码：
public void onDestroy() {
synchronized(curPlayers) {
for(List<MediaP> ms : curPlayers.values()) {
synchronized(ms) {
for(MediaP m : ms) {
synchronized(m) {
m.m.stop();
m.m.release();
}
}
}
}
curPlayers.clear();
}
}
private static class MediaP {
private MediaP(MediaPlayer m) {
this.m = m;
}
private MediaPlayer m;
private boolean wasplaying = false;
}
那里有什么我应该做的吗？
解决方法
在release()之前删除对MediaPlayer.stop()的调用.我们在Nexus 4,5,7,10和Moto X上看到过很多类似的崩溃.你可以在这里阅读更多内容
NullPointerException in MediaPlayer$EventHandler.handleMessage
据我所知,有一次他们切换到从stop()发送消息,如果你不够运气,你的release()会在检查到它不为空并尝试调用其方法后立即使对象无效.
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