如何从项目单击中的列表视图中获取歌曲

Question

我已经制作了android应用程序，其中我从移动存储中读取了所有音频歌曲，并添加了所有歌曲以自定义列表视图。 在我的列表视图中，有一个简单的文本视图，其中放置了歌曲。现在，我想添加单击侦听器到列表中，并从列表视图中获取这些歌曲，然后传递给另一个播放歌曲的活动。 我有两个类MainActivity.java

public class MainActivity extends AppCompatActivity {
ListView lv;
String[] items;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    lv = (ListView) findViewById(R.id.lvPlaylist);

    final ArrayList<File> mySongs = findSongs(Environment.getExternalStorageDirectory());
    items = new String[mySongs.size()];
    for (int i = 0; i < mySongs.size(); i++) {
        //toast(mySongs.get(i).getName().toString());
        items[i] = mySongs.get(i).getName().toString().replace(".mp3", "").replace(".wav", "");
    }

    ArrayAdapter<String> adp = new ArrayAdapter<String>(getApplicationContext(), R.layout.song_layout, R.id.textView, items);
    lv.setAdapter(adp);

    lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long l) {

            Intent intent = new Intent(MainActivity.this,Player.class);
            intent.putExtra("pos",position);
            intent.putExtra("songList",mySongs);
            startActivity(intent);
            //  startActivity(new Intent(getApplicationContext(),Player.class).putExtra("pos",position).putExtra("songlist",mySongs));

        }
    });

}

public ArrayList<File> findSongs(File root) {
    ArrayList<File> al = new ArrayList<File>();
    File[] files = root.listFiles();
    for (File singleFile : files) {
        if (singleFile.isDirectory() && !singleFile.isHidden()) {
            al.addAll(findSongs(singleFile));

        } else {
            if (singleFile.getName().endsWith(".mp3") || singleFile.getName().endsWith(".wav")) {
                al.add(singleFile);
            }
        }

    }
    return al;
}

public void toast(String text) {
    Toast.makeText(getApplicationContext(), text, Toast.LENGTH_SHORT).show();
}

}

这是Palyer.java

public class Player extends AppCompatActivity implements View.OnClickListener{
static MediaPlayer mp;
ArrayList mySongs;
int position;
Uri u;
Thread updateSeekBar;


SeekBar sb;
Button btPlay, btFF, btFB, btPv, btNxt;

MediaPlayer mediaPlayer;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_player);

    btPlay = (Button)findViewById(R.id.btPlay);
    btFF = (Button)findViewById(R.id.btFF);
    btFB = (Button)findViewById(R.id.btFB);
    btPv = (Button)findViewById(R.id.btPv);
    btNxt = (Button)findViewById(R.id.btNxt);

    btPlay.setOnClickListener(this);
    btFF.setOnClickListener(this);
    btFB.setOnClickListener(this);
    btPv.setOnClickListener(this);
    btNxt.setOnClickListener(this);

    sb = (SeekBar)findViewById(R.id.seekBar);
    updateSeekBar = new Thread(){
        @Override
        public void run() {
            //super.run();
            int totalDuration = mp.getDuration();
            int currentPosition = 0;
            sb.setMax(totalDuration);
            while(currentPosition<totalDuration){
                try{
                    sleep(500);
                    currentPosition= mp.getCurrentPosition();
                    sb.setProgress(currentPosition);
                } catch(InterruptedException e){
                    e.printStackTrace();

                }
            }
        }
    };
    if(mp!=null){
        mp.stop();
        mp.release();
    }

    Intent i = getIntent();
    mySongs.add(i.getStringExtra("songList"));
    position=i.getIntExtra("pos",0);
    u = Uri.parse(mySongs.get(position).toString());
    mp = MediaPlayer.create(getApplicationContext(),u );

    mp.release();
    mp.prepareAsync();

    mp.start();
    sb.setMax(mp.getDuration());

   updateSeekBar.start();
    sb.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
        @Override
        public void onProgressChanged(SeekBar seekBar, int progress, boolean b) {

        }

        @Override
        public void onStartTrackingTouch(SeekBar seekBar) {

        }

        @Override
        public void onStopTrackingTouch(SeekBar seekBar) {
            mp.seekTo(seekBar.getProgress());

        }
    });


}

@Override
public void onClick(View view) {
    int id = view.getId();
    switch (id){
        case R.id.btPlay:
            if(mp.isPlaying()){
                btPlay.setText(">");
                mp.pause();
            }
            else{
                mp.start();
                btPlay.setText("||");
            }
            break;
        case R.id.btFF:
            mp.seekTo(mp.getCurrentPosition()+5000);
            break;
        case R.id.btFB:
            mp.seekTo(mp.getCurrentPosition()-5000);
            break;
        case R.id.btNxt:
           mp.stop();
            mp.release();
            position = (position+1)%mySongs.size();
            u = Uri.parse(mySongs.get(position).toString());
            mp = MediaPlayer.create(getApplicationContext(),u );
            mp.start();
            sb.setMax(mp.getDuration());
            break;
        case R.id.btPv:
            mp.stop();
            mp.release();
            position = (position-1<0)? mySongs.size()-1: position-1;
            /*if(position-1<0){
                position = mySongs.size()-1;
            }
            else{
                position = position-1;
            }*/
            u = Uri.parse(mySongs.get(position).toString());
            mp = MediaPlayer.create(getApplicationContext(),u );
            mp.start();
            sb.setMax(mp.getDuration());
            break;
    }

}

}

当我启动我的应用程序并单击列表视图中的歌曲时，我的应用程序崩溃了，有人可以从项目单击监听器中的列表视图中获取歌曲吗？谢谢。

Answer 1

 Make your songs arraylist serializable as:
 public class SongsList implements Serializable
 /// getter and setter
 From Songs Files add object to SongList class then send this class 
 as:
 Intent intent = new Intent(SourceActivity.this,  
 argetActivity.class);
 intent.putExtra("SongListExtra", songList);
 On receiving activity:
 ArrayList<SongList> songlist = new ArrayList<SongList>();
 songlist = (ArrayList<SongList>) 
 getIntent().getSerializableExtra("SongListExtra");
 Instead of sending songList to player activity you can send that 
 particular song details on list item clicked according to position.
 Hope it helps..