CODEWITHSUNDEEP
androidandroid-listviewandroid-asynctask
Droidman
Droidman

Reputation: 11608

android - identify items in a ListView

I'm having some troubles with correct identification of items in a ListView.

There are 4 classes that matter, it's a lot of code so at first I'm going to explain the logic of those classes.

UPDATE

resolved 1st issue but still can't figure out what's wrong with buttons

2). I set an OnClickListener to my buttons in the Adapter's getView() method. To find out if the button is identified correctly I did nothing but just changed its background. BUT a click on a certain button forces the background of every 11th or 12th button to be changed. Can't figure it out so far.

I can't proceed to getting url and streaming audio until those problems are resolved, so any help is greatly appreciated. My classes go below, please ask if something appears unclear.

AudioList

         public class AudioList extends ListActivity {
private ListView lv;
private PlaylistLoader loader;
private AudioListAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_audio_list);
    init(); // initialize the ListView

    /*--- populate the list with user's audio in case network connection is available ---*/
    loader = new PlaylistLoader(this, lv, adapter);
    if (Utils.isNetworkAvailable(this)) {
        loader.execute();
    } else {
        APP_CONSTANTS.NO_DATA_CONNECTION(this);
    }

}

@Override
protected void onResume() {
    super.onResume();
    lv.setOnItemClickListener(new OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
                long arg3) {

            Toast.makeText(getApplicationContext(), Integer.toString(arg2),
                    Toast.LENGTH_SHORT).show();
            }
    });

}

private void init() {
    lv = getListView();
    lv.setTranscriptMode(0x00000000);
    lv.setDividerHeight(1);
    lv.setSmoothScrollbarEnabled(true);
    lv.setVerticalFadingEdgeEnabled(true);

}

PlaylistLoader

      public class PlaylistLoader extends AsyncTask<Void, Void, Void> {

private JSONObject usersPlaylist, singleJSONItem;
private JSONArray responseJSONArray;
private ListView lv;
private ArrayList<PlaylistItem> playlist;
private Activity a;
private PlaylistItem audioList;
private SharedPreferences prefs;
private ProgressDialog pd;
AudioListAdapter adapter;

public PlaylistLoader(Activity a, ListView lv, AudioListAdapter adapter) {
    this.lv = lv;
    this.a = a;
    this.adapter = adapter;
}

@Override
protected Void doInBackground(Void... arg0) {
    /*--- create new ArrayList of PlaylistItem Objects ---*/
    playlist = new ArrayList<PlaylistItem>();
    /*--- get the preferences using context of calling activity ---*/
    prefs = PreferenceManager.getDefaultSharedPreferences(a);
    try {
        /*--- download the response JSONObject from server // access_token and 
         * user_id come from activity's defaultSharedPreferences ---*/
        usersPlaylist = Utils.retrieveJsonObjectFromUrl(new URL(
                APP_CONSTANTS.REQUEST_AUDIO_LIST(prefs)), a);
        /*--- get the response array from received object ---*/
        responseJSONArray = usersPlaylist.getJSONArray("response");
        /*--- populate the ArrayList with Objects from the response array ---*/
        for (int i = 0; i < responseJSONArray.length(); i++) {
            singleJSONItem = responseJSONArray.getJSONObject(i);
            audioList = new PlaylistItem(singleJSONItem);
            playlist.add(audioList);

        }

    } catch (MalformedURLException e) {
        e.printStackTrace();
    } catch (JSONException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return null;
}

@Override
protected void onPreExecute() {
    super.onPreExecute();
    pd = new ProgressDialog(a);
    pd.setTitle("Please wait");
    pd.setMessage("Retrieving audio list...");
    pd.show();

}

@Override
protected void onPostExecute(Void result) {
    super.onPostExecute(result);
    lv.setVisibility(View.VISIBLE);
    pd.dismiss();
    /*--- set the adapter passed in constructor as an adapter for passed ListView ---*/
    adapter = new AudioListAdapter(a, R.layout.playlist_item, playlist);
    lv.setAdapter(adapter);

}
    }

AudioListAdapter

           public class AudioListAdapter extends ArrayAdapter<PlaylistItem> {
private PlaylistItem pl;
private Context context;
private int layoutResourceId;
private PlaylistItem aud;
private ArrayList<PlaylistItem> data = null;

public AudioListAdapter(Context context, int layoutResourceId,
        ArrayList<PlaylistItem> data) {
    super(context, layoutResourceId, data);
    this.layoutResourceId = layoutResourceId;
    this.context = context;
    this.data = data;

}

@Override
public PlaylistItem getItem(int position) {
    return super.getItem(position);
}

@Override
public int getCount() {
    return data.size();
}

@Override
public int getPosition(PlaylistItem item) {
    return super.getPosition(item);
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {

    pl = new PlaylistItem();
    aud = getItem(position);

    if (convertView == null) {
        LayoutInflater inflater = ((Activity) context).getLayoutInflater();
        convertView = inflater.inflate(layoutResourceId, parent, false);
        pl.btnPlay = (Button) convertView.findViewById(R.id.btn_list_play);
        pl.imgSaved = (ImageView) convertView
                .findViewById(R.id.img_list_audio_saved);
        pl.tvArtist = (TextView) convertView
                .findViewById(R.id.tvListItemArtist);
        pl.tvTitle = (TextView) convertView
                .findViewById(R.id.tvListItemSong);

        convertView.setTag(pl);
    } else {
        pl = (PlaylistItem) convertView.getTag();
        pl.btnPlay.setBackgroundResource(R.drawable.list_button_play);
    }

    pl.tvArtist.setText(aud.getArtist() + " " + "-");
    pl.tvTitle.setText(aud.getTitle());

    pl.btnPlay.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            /*--- vibrate if this option is enabled in the preferences ---*/
            if (APP_CONSTANTS.isHapticFeedbackEnabled(getContext())) {
                APP_CONSTANTS.doVibrate(getContext());

            }
         pl.btnPlay.setBackgroundResource(R.drawable.list_button_pause);

        }
    });

    return convertView;
}

PlayListItem

     public class PlaylistItem {

private String artist, title;
private JSONObject obj;
public Button btnPlay;
public TextView tvArtist, tvTitle;
public ImageView imgSaved;
public int duration;
public int audio_id;
public String url;

/*--- the constructor takes a single JSONObject from the response array ---*/
public PlaylistItem(JSONObject obj) {
    this.obj = obj;
}

public PlaylistItem() {
    // default constructor
}

/*--- the methods below return values by key from the passed JSONObject ---*/

public String getArtist() {
    try {
        artist = obj.getString("artist");
    } catch (JSONException e) {

        e.printStackTrace();
    }
    return artist;

}

public String getTitle() {
    try {
        title = obj.getString("title");
    } catch (JSONException e) {

        e.printStackTrace();
    }
    return title;
}

public int getID() {
    try {
        audio_id = obj.getInt("aid");
    } catch (JSONException e) {

        e.printStackTrace();
    }
    return audio_id;
}

public String getURL() {
    try {
        url = obj.getString("url");
    } catch (JSONException e) {

        e.printStackTrace();
    }
    return url;
}
    }

Upvotes: 0

Views: 1042

Answers (2)

Sam
Sam

Reputation: 86948

BUT a click on a certain button forces the background of every 11th or 12th button to be changed. Can't figure it out so far.

You are fighting the way ListViews recycle the row layouts.
Think of it this way: if you have a ListView with 10,000 rows but can only fit 9 of them on the screen, then it doesn't make sense to create 10,000 unique layouts. This just waste resources, instead ListView only creates ~10 layouts and reuses them.

Solution: return each row to it's default state when it is reused. In getView() add:

} else {
    pl = (PlaylistItem) convertView.getTag();
    pl.btnPlay.setBackgroundResource(R.drawable.list_button_play);
    // I guessed at the resource's name         ^^^^^^^^^^^^^^^^
}

(Also you can make a few small changes to speed up your code. For instance, you only need one OnClickListener since they all contain the same code, make this a class variable and pass this to each play Button. There are more.)

Upvotes: 1

Pragnani
Pragnani

Reputation: 20155

Edit:

Try this

Take a custom Selector in your drawable button_play.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:drawable="@drawable/pause_button"
          android:state_selected="true" />
    <item android:drawable="@drawable/play_button" />
</selector>

Modifty your adapter like this

 public class AudioListAdapter extends ArrayAdapter<PlaylistItem> {
private PlaylistItem pl;
private Context context;
private int layoutResourceId;
private PlaylistItem aud;
private ArrayList<PlaylistItem> data = null;
Button previous;

public AudioListAdapter(Context context, int layoutResourceId,
        ArrayList<PlaylistItem> data) {
    super(context, layoutResourceId, data);
    this.layoutResourceId = layoutResourceId;
    previous=new Button(context);
    this.context = context;
    this.data = data;

}

....
....

@Override
public View getView(int position, View convertView, ViewGroup parent) {

    pl = new PlaylistItem();
    aud = getItem(position);

    if (convertView == null) {
        LayoutInflater inflater = ((Activity) context).getLayoutInflater();
        convertView = inflater.inflate(layoutResourceId, parent, false);
        pl.btnPlay = (Button) convertView.findViewById(R.id.btn_list_play);
pl.btnPlay.setBackGroundResouce(R.drawable.button_play); //you can set here or in xml

        pl.imgSaved = (ImageView) convertView
                .findViewById(R.id.img_list_audio_saved);
        pl.tvArtist = (TextView) convertView
                .findViewById(R.id.tvListItemArtist);
        pl.tvTitle = (TextView) convertView
                .findViewById(R.id.tvListItemSong);

        convertView.setTag(pl);
    } else {
        pl = (PlaylistItem) convertView.getTag();
    }


    pl.tvArtist.setText(aud.getArtist() + " " + "-");
    pl.tvTitle.setText(aud.getTitle());

    pl.btnPlay.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            /*--- vibrate if this option is enabled in the preferences ---*/
            if (APP_CONSTANTS.isHapticFeedbackEnabled(getContext())) {
                APP_CONSTANTS.doVibrate(getContext());
            }
                //for some reason, the background gets changed for every 11th or 12th button in the list
             Button current=((Button)v);
              current.setSelected(true);
              previous.setSelected(false);
              previous=current;
        }
    });

    return convertView;
}

    }

The reason why your button and listitem not clickable is because Your list have a focus item button, so you need to setFocusable=false for your button. Try setting focusable=false for your button in the xml. If it is not worked for you than do like this

In your row xml file

1.set focusable=true for your button. 2.In the same set android:descendantFocusability="blocksDescendants" for your parent item.(i.e parent layout in which your views lie).

In getView() method after setting the onclickListener for the button, set focusable false for the button. It will work for sure. I hope this will help you..

Upvotes: 1

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