public class Music extends Activity implements OnCompletionListener, SeekBar.OnSeekBarChangeListener {
private ImageButton btnPlay;
private ImageButton btnForward;
private ImageButton btnBackward;
private ImageButton btnPlaylist;
private SeekBar songProgressBar;
private TextView songTitleLabel;
private TextView songCurrentDurationLabel;
private TextView songTotalDurationLabel;
// Media Player
private MediaPlayer mp;
// Handler to update UI timer, progress bar etc,.
private Handler mHandler = new Handler();;
private SongsManager songManager;
private Utilities utils;
private int seekForwardTime = 5000; // 5000 milliseconds
private int seekBackwardTime = 5000; // 5000 milliseconds
private int currentSongIndex = 0;
private boolean isShuffle = false;
private boolean isRepeat = false;
private ArrayList<HashMap<String, String>> songsList = new ArrayList<HashMap<String, String>>();
ImageButton homeButton;
ImageButton backButton;
private boolean isActivityRestarting;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.player);
// All player buttons
btnPlay = (ImageButton) findViewById(R.id.play_btn);
btnForward = (ImageButton) findViewById(R.id.forword_btn);
btnBackward = (ImageButton) findViewById(R.id.backword_btn);
btnPlaylist = (ImageButton) findViewById(R.id.btnPlaylist);
songProgressBar = (SeekBar) findViewById(R.id.songProgressBar);
songTitleLabel = (TextView) findViewById(R.id.songTitle);
songCurrentDurationLabel = (TextView) findViewById(R.id.songCurrentDurationLabel);
songTotalDurationLabel = (TextView) findViewById(R.id.songTotalDurationLabel);
// Mediaplayer
mp = new MediaPlayer();
songManager = new SongsManager();
utils = new Utilities();
homeButton = (ImageButton) findViewById(R.id.home_btn);
backButton = (ImageButton) findViewById(R.id.back_btn);
homeButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v){
Intent openStartingPoint = new Intent("org.example.app.betar.HOME");
startActivity(openStartingPoint);
}
});
backButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v){
Intent openStartingPoint = new Intent("org.example.app.betar.HOME");
startActivity(openStartingPoint);
}
});
// Listeners
songProgressBar.setOnSeekBarChangeListener(this); // Important
mp.setOnCompletionListener(this); // Important
// Getting all songs list
songsList = songManager.getPlayList();
// By default play first song
playSong(0);
/**
* Play button click event
* plays a song and changes button to pause image
* pauses a song and changes button to play image
* */
btnPlay.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// check for already playing
if(mp.isPlaying()){
if(mp!=null){
mp.pause();
// Changing button image to play button
btnPlay.setImageResource(R.drawable.btn_play);
}
}else{
// Resume song
if(mp!=null){
mp.start();
// Changing button image to pause button
btnPlay.setImageResource(R.drawable.btn_pause);
}
}
}
});
/**
* Forward button click event
* Forwards song specified seconds
* */
btnForward.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// get current song position
int currentPosition = mp.getCurrentPosition();
// check if seekForward time is lesser than song duration
if(currentPosition + seekForwardTime <= mp.getDuration()){
// forward song
mp.seekTo(currentPosition + seekForwardTime);
}else{
// forward to end position
mp.seekTo(mp.getDuration());
}
}
});
/**
* Backward button click event
* Backward song to specified seconds
* */
btnBackward.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// get current song position
int currentPosition = mp.getCurrentPosition();
// check if seekBackward time is greater than 0 sec
if(currentPosition - seekBackwardTime >= 0){
// forward song
mp.seekTo(currentPosition - seekBackwardTime);
}else{
// backward to starting position
mp.seekTo(0);
}
}
});
/**
* Button Click event for Play list click event
* Launches list activity which displays list of songs
* */
btnPlaylist.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
Intent i = new Intent(getApplicationContext(), PlayListActivity.class);
startActivityForResult(i, 100);
}
});
}
/**
* Receiving song index from playlist view
* and play the song
* */
@Override
protected void onActivityResult(int requestCode,
int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if(resultCode == 100){
currentSongIndex = data.getExtras().getInt("songIndex");
// play selected song
playSong(currentSongIndex);
}
}
/**
* Function to play a song
* @param songIndex - index of song
* */
public void playSong(int songIndex){
// Play song
try {
mp.reset();
mp.setDataSource(songsList.get(songIndex).get("songPath"));
mp.prepare();
mp.start();
// Displaying Song title
String songTitle = songsList.get(songIndex).get("songTitle");
songTitleLabel.setText(songTitle);
// Changing Button Image to pause image
btnPlay.setImageResource(R.drawable.btn_pause);
// set Progress bar values
songProgressBar.setProgress(0);
songProgressBar.setMax(100);
// Updating progress bar
updateProgressBar();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* Update timer on seekbar
* */
public void updateProgressBar() {
mHandler.postDelayed(mUpdateTimeTask, 100);
}
/**
* Background Runnable thread
* */
private Runnable mUpdateTimeTask = new Runnable() {
public void run() {
long totalDuration = mp.getDuration();
long currentDuration = mp.getCurrentPosition();
// Displaying Total Duration time
songTotalDurationLabel.setText(""+utils.milliSecondsToTimer(totalDuration));
// Displaying time completed playing
songCurrentDurationLabel.setText(""+utils.milliSecondsToTimer(currentDuration));
// Updating progress bar
int progress = (int)(utils.getProgressPercentage(currentDuration, totalDuration));
//Log.d("Progress", ""+progress);
songProgressBar.setProgress(progress);
// Running this thread after 100 milliseconds
mHandler.postDelayed(this, 100);
}
};
/**
*
* */
@Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromTouch) {
}
/**
* When user starts moving the progress handler
* */
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
// remove message Handler from updating progress bar
mHandler.removeCallbacks(mUpdateTimeTask);
}
/**
* When user stops moving the progress hanlder
* */
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
mHandler.removeCallbacks(mUpdateTimeTask);
int totalDuration = mp.getDuration();
int currentPosition = utils.progressToTimer(seekBar.getProgress(), totalDuration);
// forward or backward to certain seconds
mp.seekTo(currentPosition);
// update timer progress again
updateProgressBar();
}
/**
* On Song Playing completed
* if repeat is ON play same song again
* if shuffle is ON play random song
* */
@Override
public void onCompletion(MediaPlayer arg0) {
// check for repeat is ON or OFF
// no repeat or shuffle ON - play next song
if(currentSongIndex < (songsList.size() - 1)){
playSong(currentSongIndex + 1);
currentSongIndex = currentSongIndex + 1;
}else{
// play first song
playSong(0);
currentSongIndex = 0;
}
}
@Override
public void onDestroy(){
super.onDestroy();
mp.release();
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
//preventing default implementation previous to android.os.Build.VERSION_CODES.ECLAIR
return true;
}
return super.onKeyDown(keyCode, event);
}
}
我使用android构建了音乐播放器这个播放器是这个应用程序中更多活动的一个我从主页调用活动播放器但是当我回到主页然后再次调用播放器的活动你再次播放歌曲并且仍然播放旧音乐
当我打电话给活动播放器时，我需要继续播放歌曲，回到现在
我使用 startActivity 从主页调用活动播放器
请帮帮我