I have a ListView with a SimpleAdapter. The Data for the ListView comes from json. I want to update the ListView every 5 min. 
That works fine... But the ListView is allway a *double*. All items are to times in the ListView. Why? And wenn I update then 3 times....
I try

```
setListAdapter(null);

```

and

```
mylist.clear();

```

no effect

```
public class StartActivity extends ListActivity {
    TextView text_1,text_2 ;
    private Timer autoUpdate;
    ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();
    Button btnShowLocation;

    // GPSTracker class
    GpsData gps;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.listplaceholder);

        btnShowLocation = (Button) findViewById(R.id.report_btn);

        // show location button click event
        btnShowLocation.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View arg0) {
                Intent intent = new Intent(StartActivity.this, ReportActivity.class);
                startActivity(intent);

            }
        });

        new task().execute();
    }

     @Override
     public void onResume() {
      super.onResume();
      autoUpdate = new Timer();
      autoUpdate.schedule(new TimerTask() {
       @Override
       public void run() {
        runOnUiThread(new Runnable() {
         public void run() {
             new task().execute();
         }
        });
       }
      }, 0, 300000); // updates each 5 min
     }

class task extends AsyncTask<String, String, Void>
{
private ProgressDialog progressDialog = new ProgressDialog(StartActivity.this);
    InputStream is = null ;
    String result = "";
    protected void onPreExecute() {
       progressDialog.setMessage("Status Update...");
       progressDialog.show();
       progressDialog.setOnCancelListener(new OnCancelListener() {
    @Override
        public void onCancel(DialogInterface arg0) {
        task.this.cancel(true);
       }
    });
     }
       @Override
    protected Void doInBackground(String... params) {
           //mylist.clear();

           JSONObject json = jsonFunctions.getJSONfromURL("http://my.de", mlat, mlon);

      try{
        //String text = getString(R.string.report_TJ);
        JSONArray  earthquakes = json.getJSONArray("uTraf");

            for(int i=0;i<earthquakes.length();i++){                        
                HashMap<String, String> map = new HashMap<String, String>();    
                JSONObject e = earthquakes.getJSONObject(i);

                map.put("id",  String.valueOf(i));
                map.put("first", "Stau: " + e.getString("road") + ", " + e.getString("county"));
                map.put("second", e.getString("timestamp") + ", " + e.getString("suburb"));
                mylist.add(map);            
            }       
      }catch(JSONException e)        {
         Log.e("log_tag", "Error parsing data "+e.toString());
      }

            return null;

        }
    protected void onPostExecute(Void v) {
        //setListAdapter(null);
        ListAdapter adapter = new SimpleAdapter(StartActivity.this, mylist , R.layout.main, 
                new String[] { "first", "second" }, 
                new int[] { R.id.item_title, R.id.item_subtitle });

setListAdapter(adapter);

final ListView lv = getListView();
lv.setTextFilterEnabled(true);  
lv.setOnItemClickListener(new OnItemClickListener() {
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {              
        @SuppressWarnings("unchecked")
        HashMap<String, String> o = (HashMap<String, String>) lv.getItemAtPosition(position);                   
        Toast.makeText(StartActivity.this, "ID '" + o.get("id") + "' was clicked.", Toast.LENGTH_SHORT).show(); 

    }
});
            this.progressDialog.dismiss();

        } 
    }

@Override
public void onPause() {
 autoUpdate.cancel();
 super.onPause();
}

}

```