我正在试图找出如何在我的媒体播放器准备流媒体文件时有一个“正在加载。请等待......”的进度条。现在发生的是它在准备好歌曲后显示。我怎样才能解决这个问题?
mediaPlayerLoadingBar =ProgressDialog.show(PlaylistActivity.this, "", "Loading. Please wait...", true);
/*dubstep stream*/
try {
dubstepMediaPlayer.setDataSource(dubstepPlaylistString[0]);
dubstepMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
dubstepMediaPlayer.prepare();
} 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();
}
dubstepMediaPlayer.start();
if(dubstepMediaPlayer.isPlaying()){
mediaPlayerLoadingBar.dismiss();
}`
编辑:这是我现在的代码:
`switch(pSelection){案例1:
new AsyncTask<Void, Void, Void>(){
@Override
protected void onPreExecute(){
mediaPlayerLoadingBar =ProgressDialog.show(PlaylistActivity.this, "", "Loading. Please wait...", true);
try {
dubstepMediaPlayer.setDataSource(dubstepPlaylistString[0]);
} catch (IllegalArgumentException 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();
}
dubstepMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
}
@Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
//mediaPlayerLoadingBar =ProgressDialog.show(PlaylistActivity.this, "", "Loading. Please wait...", true);
return null;
}
protected void onPostExecute(Void result){
//mediaPlayerLoadingBar =ProgressDialog.show(PlaylistActivity.this, "", "Loading. Please wait...", true)
dubstepMediaPlayer.prepareAsync();
dubstepMediaPlayer.start();
mediaPlayerLoadingBar.dismiss();
}
}.execute();`
问题在于你在这里不做异步,你应该这样做。你应该使用AsyncTask来完成你的工作。
看看“4个步骤”,详见此处:
这4个步骤
执行异步任务时,任务将执行4个步骤:
编辑:
您可以创建一个匿名内部类来进行出价,这可能与您创建onClick处理程序的方式类似。在你的onClick做这样的事情:
//pseudo-code...
onClick(View v, ...) {
new AsyncTask<Generic1, Generic2, Generic3>() {
protected void onPreExecute() {
// do pre execute stuff...
}
protected Generic3 doInBackground(Generic1... params) {
// do background stuff...
}
protected void onPostExecute(Generic3 result) {
// do post execute stuff...
}
}.execute();
}
别忘了在这里关注你的仿制药!
如果有人仍然面临这个问题,请参阅下面的代码
AsyncTask<Void, Void, Void> task = new AsyncTask<Void, Void, Void>() {
@Override
protected void onPreExecute() {
if(translation.equals("NIV"))
{
if(AudioPlaying==false)
{
mediaPlayer = new MediaPlayer();
mediaPlayer.setOnPreparedListener(Main.this);
mediaController = new MediaController(Main.this);
}
else
mediaController.show();
}
else
Toast.makeText(getBaseContext(), "عفوا, جاري تحميل ملفات الصوت الخاصة بترجمة الفانديك ", Toast.LENGTH_LONG).show();
pd = new ProgressDialog(Main.this);
pd.setTitle("Processing...");
pd.setMessage("Please wait.");
pd.setCancelable(false);
pd.setIndeterminate(true);
pd.show();
}
@Override
protected Void doInBackground(Void... arg0) {
try {
//Do something...
//Thread.sleep(5000);
try
{
mediaPlayer.setDataSource(AudioUrlPath);
mediaPlayer.prepare();
mediaPlayer.start();
AudioPlaying=true;
}
catch (IOException e) {
Log.e("AudioFileError", "Could not open file " + AudioUrlPath + " for playback.", e);
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void result) {
if (pd!=null) {
pd.dismiss();
//b.setEnabled(true);
}
}
};
task.execute((Void[])null);
这是活动课。这里我只是展示方式。
package com.android.mediaactivity;
import android.app.Activity;
import android.os.Bundle;
import android.widget.LinearLayout;
import android.widget.ProgressBar;
public class MediaActivity extends Activity
{
public LinearLayout mainLayout;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mainLayout=(LinearLayout)findViewById(R.id.mainlinear);
MediaPlayer media=new MediaPlayer(this);
media.startPlayer();
}
}
这是mediaplayerclass。
package com.android.mediaactivity;
import java.io.IOException;
import android.media.MediaPlayer.OnPreparedListener;
public class MediaPlayer implements OnPreparedListener {
MediaActivity mediaActivity;
android.media.MediaPlayer mediaPlayer;
public MediaPlayer(MediaActivity mediaActivity) {
this.mediaActivity = mediaActivity;
}
public void startPlayer() {
mediaPlayer = new android.media.MediaPlayer();
mediaPlayer.setOnPreparedListener(this);
mediaPlayer.reset();
try {
mediaPlayer.setDataSource("");
mediaPlayer.prepareAsync();
toggleProgress(true);
} catch (IllegalArgumentException 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(); } } public void onPrepared(android.media.MediaPlayer mp) { toggleProgress(false); mediaPlayer.start(); }
public void toggleProgress(final boolean show) {
mediaActivity.runOnUiThread(new Runnable() {
public void run() {
if (show) mediaActivity.mainLayout.setVisibility(mediaActivity.mainLayout.VISIBLE);
else mediaActivity.mainLayout.setVisibility(mediaActivity.mainLayout.INVISIBLE);
}
});
}
}
}
}
这是main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent" android:id="@+id/mainlinear"
android:visibility="invisible">
<ProgressBar android:id="@+id/ProgressBar01"
android:layout_width="wrap_content" android:layout_height="wrap_content"></ProgressBar>
</LinearLayout>
当您在底层的prepare
对象上说mediaplayer
时,它内部确实做了一些准备工作 - 为文件设置提取器,设置音频解码器以解码编码的音频文件并设置音频接收器以播放原始音频数据从解码器解码。现在所有这些都需要时间,而不是瞬间完成。
因此,在您的原始代码中,您检查媒体播放器isPlaying
然后解除它,但问题是在那时媒体播放器还没有播放音频,因此您的解雇从未被调用,因此它始终可见。
你需要做的是实现监听器MediaPlayer.OnPreparedListener
,当你的应用程序调用方法onPrepared
时,调用该方法中的mediaPlayerLoadingBar.dismiss();
。
这是我的解决方案:prepareAsync函数用于准备音频,它是一个非阻塞操作(它不会阻止应用程序的主线程)。
然后我使用回调setOnPreparedListener在prepareAsync返回时收到通知,音频就绪
public void playAudio(String audioFile){
//init the progress dialog
final ProgressDialog progressDialog = new ProgressDialog(SubjectActivity.this);
try {
progressDialog.setCancelable(false);
progressDialog.setMessage(" Waiting to Prepare ...");
progressDialog.show();
// pass the url file to the media player
mediaplayer.setDataSource(audioFile);
mediaplayer.prepareAsync();
} 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();
}
//the callback gets called when prepareAsync audio file become ready,
mediaplayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
@Override
public void onPrepared(MediaPlayer mp) {
mediaplayer.start();
// cancel the dialog
progressDialog.cancel();
}
});
}