从另一个类访问列表

Question

I'm working on an audio player. I have a fragment called HomeFragment which shows the lists of the songs. When I press one of the songs an activity called SongDetailActivity opens and there is a play button called play_fab inside it. I want to create a notification when I press this play button.

I have the song lists inside the DataSource.java .

My problem is in this line

SongDetailActivity :

CreateNotification.createNotification(SongDetailActivity.this, lstSongs.get(1),R.drawable.ic_pause_black_24dp,1,lstSongs.size()-1);

lstSongs is colored red, I can't reach it. What should I do to reach lstSongs. Can somebody help please?

My codes:

SongDetailActivity.java

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

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        createChannel();
    }


    play_fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            CreateNotification.createNotification(SongDetailActivity.this, lstSongs.get(1),R.drawable.ic_pause_black_24dp,1,lstSongs.size()-1);
        }
    });

DataSource.java

public class DataSource {

public static List<Song> getMusic(){

    List<Song> lstSongs = new ArrayList<>();
    lstSongs.add(new Song("Title1","Artist1", R.drawable.cover1,"Category Name 1"));
    lstSongs.add(new Song("Title2","Artist2",R.drawable.cover2,"Category Name 2"));
    lstSongs.add(new Song("Title3","Artist3",R.drawable.cover3,"Category Name 3"));
    lstSongs.add(new Song("Title4","Artist4",R.drawable.cover4,"Category Name 4"));
    lstSongs.add(new Song("Title5","Artist5",R.drawable.cover5,"Category Name 5"));
    lstSongs.add(new Song("Title6","Artist6",R.drawable.cover6,"Category Name 6"));
    lstSongs.add(new Song("Title7","Artist7",R.drawable.cover7,"Category Name 7"));

    return lstSongs;

}

Answer 1

Create a global variable List<Song> lstSongs; and instantiate in onCreate() of SongDetailActivity as follows:

lstSongs = DataSource.getMusic();

It should serve your purpose.