用例是这样的,在 Android 中(在 Kit Kat 之上):从音频文件打开一个流,获取它的属性,修改内存缓冲区并播放结果。
我想知道如何 1)从音频文件正确创建流; 2) 像 javax.sound.sampled.AudioFormat 一样获取其属性( channel 、编码、长度),但使用来自 android.media 框架的方法。
我知道如何从二进制构建一个流,向它添加音频属性然后播放它。我想做另一种方式,并使用 Android 框架的最新类从现有的声音文件头中提取这些属性( channel 、编码)。
谢谢!
最佳答案
这是完整的流媒体类使用:
public class MainActivity extends Activity implements OnClickListener,
OnTouchListener, OnCompletionListener, OnBufferingUpdateListener {
private Button btn_play, btn_pause, btn_stop;
private SeekBar seekBar;
private MediaPlayer mediaPlayer;
private int lengthOfAudio;
private final String URL = "http://songspkcompilations.com/indian/soulfularijit/%5BSongs.PK%5D%2012%20-%20Mickey%20Virus%20-%20Tose%20Naina.mp3";
private static final int MINUTES_IN_AN_HOUR = 60;
private static final int SECONDS_IN_A_MINUTE = 60;
private final Handler handler = new Handler();
private boolean is_loading = true;
private boolean is_stopped = false;
private final Runnable r = new Runnable() {
@Override
public void run() {
updateSeekProgress();
}
};
private TextView txtTime;
private ProgressBar musicProgress;
private ImageView artistImg;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initialize_Controls();
}
private void initialize_Controls() {
btn_play = (Button) findViewById(R.id.btn_play);
btn_play.setOnClickListener(this);
btn_pause = (Button) findViewById(R.id.btn_pause);
btn_pause.setOnClickListener(this);
btn_pause.setEnabled(false);
btn_stop = (Button) findViewById(R.id.btn_stop);
btn_stop.setOnClickListener(this);
btn_stop.setEnabled(false);
musicProgress = (ProgressBar) findViewById(R.id.progress);
artistImg = (ImageView) findViewById(R.id.artistImg);
seekBar = (SeekBar) findViewById(R.id.seekBar);
seekBar.setOnTouchListener(this);
txtTime = (TextView) findViewById(R.id.time);
mediaPlayer = new MediaPlayer();
mediaPlayer.setOnBufferingUpdateListener(this);
mediaPlayer.setOnCompletionListener(this);
}
@Override
public void onBufferingUpdate(MediaPlayer mediaPlayer, int percent) {
seekBar.setSecondaryProgress(percent);
}
@Override
public void onCompletion(MediaPlayer mp) {
btn_play.setEnabled(true);
btn_pause.setEnabled(false);
btn_stop.setEnabled(false);
}
@Override
public boolean onTouch(View v, MotionEvent event) {
if (mediaPlayer.isPlaying()) {
SeekBar tmpSeekBar = (SeekBar) v;
mediaPlayer
.seekTo((lengthOfAudio / 100) * tmpSeekBar.getProgress());
}
return false;
}
@Override
public void onClick(View view) {
try {
mediaPlayer.setDataSource(URL);
mediaPlayer.prepare();
lengthOfAudio = mediaPlayer.getDuration();
} catch (Exception e) {
// Log.e("Error", e.getMessage());
}
switch (view.getId()) {
case R.id.btn_play:
if (is_stopped) {
is_stopped = false;
mediaPlayer.seekTo(0);
}
playAudio();
break;
case R.id.btn_pause:
pauseAudio();
break;
case R.id.btn_stop:
stopAudio();
break;
default:
break;
}
updateSeekProgress();
}
private void updateSeekProgress() {
if (mediaPlayer.isPlaying()) {
if (is_loading) {
is_loading = false;
musicProgress.setVisibility(View.GONE);
artistImg.setVisibility(View.VISIBLE);
}
int progress = (int) (((float) mediaPlayer.getCurrentPosition() / lengthOfAudio) * 100);
int remainSec = (lengthOfAudio - mediaPlayer.getCurrentPosition()) / 1000;
seekBar.setProgress(progress);
txtTime.setText("" + timeConversion(remainSec));
handler.postDelayed(r, 1000);
}
}
private void stopAudio() {
if (mediaPlayer != null) {
mediaPlayer.pause();
is_stopped = true;
}
seekBar.setProgress(0);
seekBar.setSecondaryProgress(0);
txtTime.setText("" + timeConversion(lengthOfAudio / 1000));
btn_play.setEnabled(true);
btn_pause.setEnabled(false);
btn_stop.setEnabled(false);
}
private void pauseAudio() {
if (mediaPlayer != null) {
mediaPlayer.pause();
}
btn_play.setEnabled(true);
btn_pause.setEnabled(false);
}
private void playAudio() {
if (mediaPlayer != null) {
mediaPlayer.start();
}
btn_play.setEnabled(false);
btn_pause.setEnabled(true);
btn_stop.setEnabled(true);
}
private static String timeConversion(int totalSeconds) {
int hours = totalSeconds / MINUTES_IN_AN_HOUR / SECONDS_IN_A_MINUTE;
int minutes = (totalSeconds - (hoursToSeconds(hours)))
/ SECONDS_IN_A_MINUTE;
int seconds = totalSeconds
- ((hoursToSeconds(hours)) + (minutesToSeconds(minutes)));
return hours + ":" + minutes + ":" + seconds;
}
private static int hoursToSeconds(int hours) {
return hours * MINUTES_IN_AN_HOUR * SECONDS_IN_A_MINUTE;
}
private static int minutesToSeconds(int minutes) {
return minutes * SECONDS_IN_A_MINUTE;
}
class PlayTask extends AsyncTask<String, Integer, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected String doInBackground(String... params) {
try {
mediaPlayer.setDataSource(URL);
mediaPlayer.prepare();
lengthOfAudio = mediaPlayer.getDuration();
} catch (Exception e) {
// Log.e("Error", e.getMessage());
}
return null;
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
playAudio();
updateSeekProgress();
}
}
@Override
protected void onResume() {
super.onResume();
new PlayTask().execute();
}
@Override
public void onBackPressed() {
super.onBackPressed();
pauseAudio();
finish();
}
}
关于java - 在Android中从音频文件创建流,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/28323359/