如何从 onitemclick 获取数据并将其显示在另一个活动（Android Dev）上？

Question

I am very new to Android and Java dev, sorry in advance.

I am making a simple music player app.

Right now my app gets storage data from the phone (it finds mp3 files) and displays both the title and artist in a ListView.

When a song item in the list is clicked it changes screens to the PlaySongActivity.Java via an intent. On the Activity_Play_Song.xml I set up two text views. I want to make it so that whenever an item is clicked the title and artist is transferred into the two text views in the Activity_Play_Song.xml texts.

How can I do this?

Here is my code:

MainActivity

ArrayList<String> arrayList;
ListView listView;
ArrayAdapter<String> adapter;

 public void getMusic(){
    ContentResolver contentResolver = getContentResolver();
    Uri songUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
    Cursor songCursor = contentResolver.query(songUri, null, null, null, null);

    if(songCursor != null && songCursor.moveToFirst()){
        int songTitle = songCursor.getColumnIndex(MediaStore.Audio.Media.TITLE);
        int songArtist = songCursor.getColumnIndex(MediaStore.Audio.Media.ARTIST);

        do{
            String currentTitle = songCursor.getString((songTitle));
            String currentArtist = songCursor.getString((songArtist));
            arrayList.add(currentTitle+ "\n" + currentArtist);
        } while (songCursor.moveToNext());
    }
}

public void doStuff(){
    listView = (ListView) findViewById(R.id.listView);
    arrayList = new ArrayList<>();
    getMusic();
    adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, arrayList);
    listView.setAdapter(adapter);

    listView.setOnItemClickListener(new AdapterView.OnItemClickListener(){
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            Intent i = new Intent(MainActivity.this, PlaySongActivity.class);
            startActivity(i);

        }
    });


}

Currently, the PlaySongsActivity only contains the default onCreate code and the activity_play_songs.xml has two TextViews where I want the title and artist to go.

Answer 1

Anjali bhardwaj.

To send information from one activity to another using intent do this:

Intent i = new Intent(MainActivity.this, PlaySongActivity.class);

//Here we store the title and author strings using .putExtra("Name", Value)

i.putExtra("ArtistString", currentArtist);
i.putExtra("TitleString", currentTitle);

startActivity(i);

Now it is stored and will be sent over to the activity that you are starting.

To get the information in the receiving activity

/*gets the information from the intent that was passed and casts it to a Intent object*/
Intent intent = getIntent();

//gets the strings from the intent
String artist = intent.getStringExtra("ArtistString");
String title = intent.getStringExtra("TitleString");

Now you can do whatever you want with this string. Hope this helps!

--UPDATE--

Example

public class SomeClass{

//declare them outside of the method so that they can be accessed by any method. 
//I just set them to nothing so that you dont get NULLPOINTEREXCEPTIONs
String currentTitle = "nothing";
String currentArtist = "nothing";

public void getMusic(){
   //set the value of the strings in here
}

public void doStuff(){
  //Access them here
}

}