选择一个音乐文件的MediaPlayer播放 [英] Select a music file to play with MediaPlayer
问题描述
我是新的机器人编程，现在我与我的应用程序有问题。我打算与功能codeA MediaPlayer的应用程序：选择存储使用的意图，然后开始播放该文件的文件。我用MediaPlayer.create（背景下，URI）的方法，但现在我得到的错误
I'm new in android programming and now i get a problem with my app. I intend to code a MediaPlayer application with feature: select a file from storage using intent then start playing that file. I use "MediaPlayer.create(context, uri)" method but currently i got error
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//openFile();
Button openFile = (Button) this.findViewById(R.id.ButtonOpen);
openFile.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent chooseFile;
Intent intent;
chooseFile = new Intent(Intent.ACTION_GET_CONTENT);
chooseFile.setType("file/*");
intent = Intent.createChooser(chooseFile, "Choose a file");
startActivityForResult(intent, ACTIVITY_CHOOSE_FILE);
Uri uri = intent.getData();
initViews(uri);
}
});
}
private void initViews(Uri uri) {
mButtonPlayStop = (Button) findViewById(R.id.ButtonPlayStop);
mButtonPlayStop.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
buttonClick();
}
});
mMediaPlayer = MediaPlayer.create(this, uri);
}
private void starPlayProgressUpdater() {
mSeekBar.setProgress(mMediaPlayer.getCurrentPosition());
if (mMediaPlayer.isPlaying()) {
Runnable notification = new Runnable() {
@Override
public void run() {
starPlayProgressUpdater();
}
};
mHandler.postDelayed(notification, 1000);
} else {
mMediaPlayer.pause();
mButtonPlayStop.setText(getString(R.string.play_str));
mSeekBar.setProgress(0);
}
}
private void buttonClick() {
if (mButtonPlayStop.getText() == getString(R.string.play_str)) {
mButtonPlayStop.setText(getString(R.string.pause_str));
try {
mMediaPlayer.start();
starPlayProgressUpdater();
} catch (IllegalStateException e) {
mMediaPlayer.pause();
}
} else {
mButtonPlayStop.setText(getString(R.string.play_str));
mMediaPlayer.pause();
}
}
和它引发NullPointerException异常的mMediaPlayer = MediaPlayer.create（这一点，URI）;。它有问题的URI。谁能公会我的方法是什么？
And it throws NullPointerException in "mMediaPlayer = MediaPlayer.create(this, uri);". It has problem with the uri. Could anyone guild me the way?
由于Ilango J，I修订我的code，那么现在我可以选择和播放音乐文件。但我的expecteation是选择文件，然后点击后，只玩上播放/暂停按钮（带进度条），但我得到了新的NullPointerException我buttonClick
Thanks Ilango j, i revised my code then now i could select and play a music file. But my expecteation is select file then only play after click on Play/Pause button (with progress bar) but i got new NullPointerException with my buttonClick
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mContext = (Context) getApplicationContext();
Button openFile = (Button) this.findViewById(R.id.ButtonOpen);
openFile.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
initView();
}
});
}
private void initView() {
mButtonPlayStop = (Button) findViewById(R.id.ButtonPlayStop);
mButtonPlayStop.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
buttonClick();
}
});
Intent intent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Audio.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(intent, 10);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == RESULT_OK && requestCode == 10) {
Uri uri = data.getData();
mMediaPlayer = MediaPlayer.create(mContext, uri);
mSeekBar = (SeekBar) findViewById(R.id.SeekBar01);
mSeekBar.setMax(mMediaPlayer.getDuration());
mSeekBar.setOnTouchListener(new OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
seekChange(v);
return false;
}
});
}
}
private void starPlayProgressUpdater() {
mSeekBar.setProgress(mMediaPlayer.getCurrentPosition());
if (mMediaPlayer.isPlaying()) {
Runnable notification = new Runnable() {
@Override
public void run() {
starPlayProgressUpdater();
}
};
mHandler.postDelayed(notification, 1000);
} else {
mMediaPlayer.pause();
mButtonPlayStop.setText(getString(R.string.play_str));
mSeekBar.setProgress(0);
}
}
private void seekChange(View v) {
if (mMediaPlayer.isPlaying()) {
SeekBar sb = (SeekBar) v;
mMediaPlayer.seekTo(sb.getProgress());
}
}
private void buttonClick() {
if (mButtonPlayStop.getText().equals(getString(R.string.play_str))) {
mButtonPlayStop.setText(getString(R.string.pause_str));
try {
mMediaPlayer.start();
starPlayProgressUpdater();
} catch (IllegalStateException e) {
mMediaPlayer.pause();
}
} else {
mButtonPlayStop.setText(getString(R.string.play_str));
mMediaPlayer.pause();
}
}
您能给一个建议？
Could you please give an advice?
推荐答案
首先开始的活动，从SD卡的PIC的媒体文件。更换以下code
First start activity to pic media file from sd card. Replace the following code
Button openFile = (Button) this.findViewById(R.id.ButtonOpen);
openFile.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Audio.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(intent, 10);
}
});
那么在添加以下code。在 onActivityResult
Then in add the following code in onActivityResult
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if(requestCode == RESULT_OK && requestCode == 10){
Uri uriSound=data.getData();
play(this, uriSound);
}
}
和调用下面的方法来创建媒体播放器和播放选定的音频文件。
And call the below method to create media player and play selected audio file.
private void play(Context context, Uri uri) {
try {
MediaPlayer mp = new MediaPlayer();
mp.setDataSource(context, uri);
mp.start();
} 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();
}
}
这篇关于选择一个音乐文件的MediaPlayer播放的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
