Load ListView dynamically. Refresh ListView every n sec.

Below is my code that shows a combo box overlay that shows some information. I am updating the data after every 7 sec

. I want to delete the first list before displaying the other. In case of occasion, ListView

overlap.

public class OverlayShowingService extends Service implements OnTouchListener,               OnClickListener {

private View topLeftView;

private Button overlayedButton;
ArrayList<String> list = new ArrayList<String>();

/** Declaring an ArrayAdapter to set items to ListView */
ArrayAdapter<String> adapter;
private float offsetX;
private float offsetY;
private int originalXPos;
private int originalYPos;
private boolean moving;
private WindowManager wm;
DispAsync dis;
ListView listView;

@Override
public IBinder onBind(Intent intent) {
return null;
}

@Override
public void onCreate() {
super.onCreate();
}


@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    // TODO Auto-generated method stub

    Toast.makeText(getApplicationContext(),"onStartCommand", Toast.LENGTH_LONG).show();

    listView = new ListView(getApplicationContext());
    listView.setAlpha(0.0f);
    listView.setBackgroundColor(0x55fe4444);



       final Handler handler = new Handler();
        Timer timer = new Timer();
        TimerTask doAsynchronousTask = new TimerTask() {       
            @Override
            public void run() {
                handler.post(new Runnable() {
                    public void run() {       
                        try {
                            dis=new DispAsync();
                            dis.execute();
                        } catch (Exception e) {
                            // TODO Auto-generated catch block
                        }
                    }
                });
            }
        };
        timer.schedule(doAsynchronousTask, 0, 7000); //execute in every 50000 ms



    return super.onStartCommand(intent, flags, startId);
}

public class DispAsync extends AsyncTask<Void, Void, String>
{
    @Override
    protected void onPreExecute() {
        // TODO Auto-generated method stub

        Toast.makeText(getApplicationContext(),"onPre", Toast.LENGTH_LONG).show();
        //list.clear();
        adapter = new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_list_item_1, list);
        listView.setAdapter(adapter);
        super.onPreExecute();
    }

    @Override
    protected String doInBackground(Void... params) {
        // TODO Auto-generated method stub
        String line = null;
        wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE);


        try
        {

            line = dynamic data;
            while (line != null) {
                if(line.contains("com"))
                {list.add(line);}
                line = reader.readLine();
                i++;
            }

            p.waitFor();
        }
        catch(Exception e){}



        return line;
    }

    @Override
    protected void onPostExecute(String result) {
        // TODO Auto-generated method stub

        Toast.makeText(getApplicationContext(),"onPost", Toast.LENGTH_LONG).show();
        WindowManager.LayoutParams params = new WindowManager.LayoutParams(WindowManager.LayoutParams.WRAP_CONTENT, WindowManager.LayoutParams.WRAP_CONTENT, WindowManager.LayoutParams.TYPE_SYSTEM_ALERT, WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE, PixelFormat.TRANSLUCENT);
        params.gravity = Gravity.LEFT | Gravity.TOP;
        params.x = 0;
        params.y = 0;
        //adapter.notifyDataSetChanged();
        wm.addView(listView, params);

   /*   topLeftView = new View(getApplicationContext());
        WindowManager.LayoutParams topLeftParams = new WindowManager.LayoutParams(WindowManager.LayoutParams.WRAP_CONTENT, WindowManager.LayoutParams.WRAP_CONTENT, WindowManager.LayoutParams.TYPE_SYSTEM_ALERT, WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE, PixelFormat.TRANSLUCENT);
        topLeftParams.gravity = Gravity.LEFT | Gravity.TOP;
        topLeftParams.x = 0;
        topLeftParams.y = 0;
        topLeftParams.width = 0;
        topLeftParams.height = 0;
        wm.addView(topLeftView, topLeftParams);*/

        super.onPostExecute(result);
    }

}
@Override
public void onDestroy() {
super.onDestroy();
if (overlayedButton != null) {
    wm.removeView(overlayedButton);
    wm.removeView(topLeftView);
    overlayedButton = null;
    topLeftView = null;
}
}

@Override
public boolean onTouch(View v, MotionEvent event) {

if (event.getAction() == MotionEvent.ACTION_DOWN) {
    float x = event.getRawX();
    float y = event.getRawY();

    moving = false;

    int[] location = new int[2];
    overlayedButton.getLocationOnScreen(location);

    originalXPos = location[0];
    originalYPos = location[1];

    offsetX = originalXPos - x;
    offsetY = originalYPos - y;

} else if (event.getAction() == MotionEvent.ACTION_MOVE) {
    int[] topLeftLocationOnScreen = new int[2];
    topLeftView.getLocationOnScreen(topLeftLocationOnScreen);

    System.out.println("topLeftY="+topLeftLocationOnScreen[1]);
    System.out.println("originalY="+originalYPos);

    float x = event.getRawX();
    float y = event.getRawY();

    WindowManager.LayoutParams params = (LayoutParams) overlayedButton.getLayoutParams();

    int newX = (int) (offsetX + x);
    int newY = (int) (offsetY + y);

    if (Math.abs(newX - originalXPos) < 1 && Math.abs(newY - originalYPos) < 1 && !moving) {
    return false;
    }

    params.x = newX - (topLeftLocationOnScreen[0]);
    params.y = newY - (topLeftLocationOnScreen[1]);

    wm.updateViewLayout(overlayedButton, params);
    moving = true;
} else if (event.getAction() == MotionEvent.ACTION_UP) {
    if (moving) {
    return true;
    }
}

return false;
}

@Override
public void onClick(View v) {
Toast.makeText(this, "Overlay button click event", Toast.LENGTH_SHORT).show();
} 
}

      

        
        
        
      

    

LogCat

08-11 16:00:55.175: E/AndroidRuntime(11498): FATAL EXCEPTION: main
08-11 16:00:55.175: E/AndroidRuntime(11498): Process: de.mobilej.overlay, PID: 11498
08-11 16:00:55.175: E/AndroidRuntime(11498): java.lang.IllegalStateException: View android.widget.ListView{41db9c50 V.ED.VC. ......I. 0,0-480,422} has already been added to the window manager.
08-11 16:00:55.175: E/AndroidRuntime(11498):    at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:232)
08-11 16:00:55.175: E/AndroidRuntime(11498):    at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:69)
08-11 16:00:55.175: E/AndroidRuntime(11498):    at de.mobilej.overlay.OverlayShowingService$DispAsync.onPostExecute(OverlayShowingService.java:151)
08-11 16:00:55.175: E/AndroidRuntime(11498):    at de.mobilej.overlay.OverlayShowingService$DispAsync.onPostExecute(OverlayShowingService.java:1)
08-11 16:00:55.175: E/AndroidRuntime(11498):    at android.os.AsyncTask.finish(AsyncTask.java:632)
08-11 16:00:55.175: E/AndroidRuntime(11498):    at android.os.AsyncTask.access$600(AsyncTask.java:177)
08-11 16:00:55.175: E/AndroidRuntime(11498):    at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
08-11 16:00:55.175: E/AndroidRuntime(11498):    at android.os.Handler.dispatchMessage(Handler.java:110)
08-11 16:00:55.175: E/AndroidRuntime(11498):    at android.os.Looper.loop(Looper.java:193)
08-11 16:00:55.175: E/AndroidRuntime(11498):    at android.app.ActivityThread.main(ActivityThread.java:5388)
08-11 16:00:55.175: E/AndroidRuntime(11498):    at java.lang.reflect.Method.invokeNative(Native Method)
08-11 16:00:55.175: E/AndroidRuntime(11498):    at java.lang.reflect.Method.invoke(Method.java:515)