在Listview中加载。 将最后一个条目中的数据加载到所有行中

Question

I'm trying to make a list of songs. Each list item should contain title, artist, time the song starts and some album art. I can't seem to get it to work properly, each time I try it only loads the data from the last entry into all the rows. I've read about ViewHolders and image loading libraries and tried implementing what I found with no luck.

Here's my code:

public class MyAdapter extends SimpleAdapter {

private static LayoutInflater inflater = null;
List data;

public MyAdapter(Context context, List<? extends Map<String, ?>> data,
        int resource, String[] from, int[] to) {
    super(context, data, resource, from, to);
    this.data = data;
    inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

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

    View vi = convertView;
    String imgURL = SongListFragment.imgURL;

    if(convertView == null){

        vi = inflater.inflate(R.layout.custom_listitem, null);

        TextView title = (TextView) vi.findViewById(R.id.title);
        TextView artist = (TextView) vi.findViewById(R.id.artist);
        TextView timeInfo = (TextView) vi.findViewById(R.id.timeInfo);

        title.setText(SongListFragment.title);
        artist.setText(SongListFragment.artist);
        timeInfo.setText(SongListFragment.starttime);

        Picasso.with(vi.getContext()).load(imgURL).into((ImageView)vi.findViewById(R.id.img));
        Log.d("Image", imgURL);

    }       

    return vi;

}

}

---

public class HttpGetTask extends AsyncTask<String, Void, String> {

interface OnHttpGetListener{

    public void httpGetCompleted(String response);
    public void httpGetFailed(String error);

}

private OnHttpGetListener mListener;
private boolean mGetFailed;
private AndroidHttpClient client;

public HttpGetTask(OnHttpGetListener listener) {

    mListener = listener;
    client = AndroidHttpClient.newInstance("Android");

}

@Override
protected String doInBackground(String... params) {

    try {

        HttpGet uri = new HttpGet(params[0]);

        HttpResponse resp = client.execute(uri);

        ByteArrayOutputStream out = new ByteArrayOutputStream();
        resp.getEntity().writeTo(out);
        resp.getEntity().consumeContent();
        out.close();
        client.close();
        return out.toString();

    } catch (Exception e) {

        mGetFailed = true;
        e.printStackTrace();
        return e.getMessage();

    }

}

@Override
protected void onPostExecute(String response) {

    if(mGetFailed) {

            mListener.httpGetFailed(response);

    } else {

            mListener.httpGetCompleted(response);

    }

   }

}

---

public class SongListFragment extends Fragment implements OnHttpGetListener {

ListView listview;
ArrayList<HashMap<String, String>> listEntries = new ArrayList<HashMap<String, String>>();
static String imgURL = null;
static String title = null;
static String artist = null;
static String starttime = null;
static String endtime = null;

public SongListFragment() {

}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.listview_fragment, container, false); 
    listview = (ListView) rootView.findViewById(R.id.songlist);
    getJSON();

    return rootView;

}

private void getJSON(){

    HttpGetTask jsonGetter = new HttpGetTask(this); //registers to listen callbacks
    final String jsonUrl = "http://stark-castle-5854.herokuapp.com/songlist"; //url to json
    jsonGetter.execute(jsonUrl); //starts the async task

}

public void httpGetCompleted(String response) {

    // this gets called when the background task
    // to get json is completed without errors            
    try {

        JSONArray newJArray = new JSONArray(response);

        for(int i = 0; i < newJArray.length(); i++){

            JSONObject json = newJArray.getJSONObject(i);
            title = json.getString("title");
            artist = json.getString("artist");
            starttime = json.getString("starttimeutc");
            endtime = json.getString("stoptimeutc");

            //all entries do not have an img resource
            if(json.has("img")){
                imgURL = json.getString("img");
            }else{                  
                imgURL = null;
            }

            long sTime = Long.parseLong(starttime);
            Date date = new Date(sTime);
            SimpleDateFormat sdf = new SimpleDateFormat("E MMM dd, HH:mm:ss");
            sdf.setTimeZone(TimeZone.getTimeZone("GMT+1"));
            String formattedDate = sdf.format(date);

            Log.d("test", "Time: " + date);

            //hashmap to store values for the listview in
            HashMap<String, String> map = new HashMap<String, String>();
            map.put("Title", title);
            map.put("Artist", artist);
            map.put("Start", "Starts: " + formattedDate);
            map.put("End", endtime);
            map.put("ImgURL", imgURL);

            //add hashmap values to arraylist
            listEntries.add(map);           

            Log.d("test", "Success! Artist: " + artist +
                    " Title: " + title +
                    " Start: " + starttime +
                    " End: " + endtime +
                    " ImgURL: " + imgURL);          
        }

        //add arraylist to listview
        ListAdapter adapter = new MyAdapter(getActivity(), listEntries,
                R.layout.custom_listitem,
                new String[] { "Title", "Artist", "Start"}, new int[] {
                    R.id.title, R.id.artist, R.id.timeInfo});

        listview.setAdapter(adapter);

        //Picasso.with(getActivity()).load("http://java.sogeti.nl/JavaBlog/wp-content/uploads/2009/04/android_icon_256.png").into((ImageView)getView().findViewById(R.id.img));

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

  }

public void httpGetFailed(String error) {
    // this gets called when the background task fails to get json
    Log.e("GetFail", error); // printing to error            
}

 }            

Please help me StackOverflow, you're my only hope.

Answer 1

In your fragment, you are saving data in static variables. In this case after executing the for loop, the last entries will be saved in all those static variables. So there is only one entry which is last, stored. And in getview view you are accessing those variables every time, which means you are accessing same values for all rows.

To solve this, you need to access the data which you are passing as List(Maps). Do a get call on this and store it as object. Then get the properties of those objects.

Something like this in your adapters getview()

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

    View vi = convertView;
    String imgURL = SongListFragment.imgURL;

    if(convertView == null){

        vi = inflater.inflate(R.layout.custom_listitem, null);

        TextView title = (TextView) vi.findViewById(R.id.title);
        TextView artist = (TextView) vi.findViewById(R.id.artist);
        TextView timeInfo = (TextView) vi.findViewById(R.id.timeInfo);

    // NOTE THAT THIS PSEUDO CODE YOU NEED TO GET THE LIST POSITION AND MAP POSITION HERE TO ACCESS TITLE<ARTIST AND STARTTIME.
        title.setText(data.get(position).title);
        artist.setText(data.get(position).artist);
        timeInfo.setText(data.get(position).starttime);

       Picasso.with(vi.getContext()).load(imgURL).into((ImageView)vi.findViewById(R.id.img));
        Log.d("Image", imgURL);
    }       
    return vi;
}

Also I would suggest you to use ViewHolder pattern in getView() which is a standard way of inflating data inside Listview.

UPDATE:

title.setText(data.get(position).get("Title"));
artist.setText(data.get(position).get("Artist"));
timeInfo.setText(data.get(position).get("Start"));

Something like above should help you to get the data from list of hashmaps.

Hope you understood and hope this helps.