JsonAdapter can't print the data

Question

I follow this video try to get data from mongodb get the JsonArray from mongodb , and use debug mode check the class JsonTest.java : ArrayList<JsonSongs> songlist; have 21 data in it , and all correct , and the listview has 21 row show up , but somehow the data did't show on the textview ,

I think the Class JsonTest.java : ˋArrayList songlist;did pass the data to class JsonSongAdapter.java ˋArrayList<JsonSongs> songlist; right? please help , stuck here for hours

JsonTest.java

public class JsonTest extends Activity {

ListView list;
ArrayList<JsonSongs> songlist;
   private TextView test;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.jsonmain);
    list = (ListView)findViewById(R.id.JsonlistView);
    songlist = new ArrayList<JsonSongs>();
    new JsonTalk().execute("http://192.168.1.102:3000/songs");

       }





class JsonTalk extends AsyncTask< String , String ,String>{

    @Override
    protected String doInBackground(String... params) {
        HttpURLConnection connection = null;
        BufferedReader reader = null;

        try {
            URL url = new URL(params[0]);
            connection = (HttpURLConnection) url.openConnection();
            connection.connect();

            InputStream stream = connection.getInputStream();
            reader = new BufferedReader(new InputStreamReader(stream));
            StringBuffer buffer = new StringBuffer();
            String line = "";
            while ((line = reader.readLine()) != null) {
                buffer.append(line);
            }
            String finalJson = buffer.toString();
           // JSONObject parentJsonObject = new JSONObject(finalJson);
            JSONArray jsonArray = new JSONArray(finalJson);
            JsonSongs jsonSongs = new JsonSongs();
            for (int i = 0 ; i < jsonArray.length();i++){
                JSONObject finaObject = jsonArray.getJSONObject(i);
                jsonSongs.set_id(finaObject.getString("_id"));
                jsonSongs.setDecade(finaObject.getString("decade"));
                jsonSongs.setArtist(finaObject.getString("artist"));
                jsonSongs.setSong(finaObject.getString("song"));
                jsonSongs.setWeeksAtOne(finaObject.getInt("weeksAtOne"));
                songlist.add(jsonSongs);
            }

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

        finally {
            if (connection != null) {
                connection.disconnect();
            }
            try {
                if (reader != null) {
                    reader.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return null;
    }

    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);
        if(result == null){
            JsonSonAdapter adapter = new JsonSonAdapter(getApplicationContext(),R.layout.jsonlayout,songlist);
            list.setAdapter(adapter);
        }else {
            Toast.makeText(JsonTest.this,"NOP",Toast.LENGTH_LONG).show();
        }
    }
}
}

JsonSonAdapter

public class JsonSonAdapter extends ArrayAdapter<JsonSongs> {
ArrayList<JsonSongs> songList;
int Resource;
Context context;
LayoutInflater vi;

public JsonSonAdapter(Context context, int resource, ArrayList<JsonSongs> objects) {
    super(context, resource, objects);
    songList = objects;
    Resource = resource;
    this.context = context;
    vi = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

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

    ViewHolder holder;
    if(convertView == null){
       convertView = vi.inflate(Resource,null);
        holder = new ViewHolder();
        holder.textJson_ID=(TextView)convertView.findViewById(R.id.textJson_ID);
        holder.textJSONname=(TextView)convertView.findViewById(R.id.textJSONname);
        holder.textJsonSong=(TextView)convertView.findViewById(R.id.textJsonSong);
        holder.textJsonYear=(TextView)convertView.findViewById(R.id.textJsonYear);
        holder.textJsonWeeks=(TextView)convertView.findViewById(R.id.textJsonWeeks);
        convertView.setTag(holder);
    }else {
        holder = (ViewHolder)convertView.getTag();
    }

    return convertView;
}

static class ViewHolder{

 public TextView textJsonYear;
 public TextView textJSONname;
 public TextView textJsonSong;
 public TextView textJsonWeeks;
 public TextView textJson_ID;
 }

}

JsonSongs

public class JsonSongs {

private String _id;
private String decade;
private String artist;
private String song;
private int weeksAtOne;

public String get_id() {
    return _id;
}

public void set_id(String _id) {
    this._id = _id;
}

public String getArtist() {
    return artist;
}

public void setArtist(String artist) {
    this.artist = artist;
}

public String getDecade() {
    return decade;
}

public void setDecade(String decade) {
    this.decade = decade;
}

public String getSong() {
    return song;
}

public void setSong(String song) {
    this.song = song;
}

public int getWeeksAtOne() {
    return weeksAtOne;
}

public void setWeeksAtOne(int weeksAtOne) {
    this.weeksAtOne = weeksAtOne;
}




}

Answer 1

but somehow the data did't show on the textview ,

You set it nowhere so no wonders. You need to call setText() on your EditTexts (in getView()) once you done with convertView to populate it with data.

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

    ViewHolder holder;
    if(convertView == null){
       convertView = vi.inflate(Resource,null);
        holder = new ViewHolder();
        holder.textJson_ID=(TextView)convertView.findViewById(R.id.textJson_ID);
        ...
        convertView.setTag(holder);
    }else {
        holder = (ViewHolder)convertView.getTag();
    }


    // populate it with data
    JsonSongs song = songs.get(position);
    holder.textJson_ID.setText(song.getSomething());
    ...


    return convertView;
}

PS: JsonSongs should rather be named JsonSong. And you got quite a mess in naming pattern.