OnTouch in MapView only fires the first time

amandion picture amandion · Sep 8, 2010 · Viewed 7.8k times · Source

I'm trying to implement a double-tap zoom like function in my MapView. The event always fires the first time, but never subsequent times. Below is my code. I have a feeling it has something to do with the map controller getting lost after the first time the event is fired.

import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapController;
import com.google.android.maps.MapView;

public class mainmap extends MapActivity implements OnTouchListener{

    long lasttime = -1;
    MapController mapc;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        MapView mapView = (MapView) findViewById(R.id.mapview);
        mapView.setBuiltInZoomControls(true);
        mapc = mapView.getController();
        mapView.setOnTouchListener(this);       
    }

    @Override
    protected boolean isRouteDisplayed() {
        // TODO Auto-generated method stub
        return false;
    }

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        if (event.getAction() == MotionEvent.ACTION_DOWN){

            if(event.getEventTime()-lasttime<2000){
                mapc.zoomInFixing((int)event.getX(),(int)event.getY());             
            }
        }       
        lasttime=event.getEventTime();
        return true;
    }

  }

I have also tried editing the OnTouch method to cast the incoming View to a MapView, getting the controller while the event is fired. However, I get the same results where the first event is fired but not subsequent ones.

public boolean onTouch(View v, MotionEvent event) {
        if (event.getAction() == MotionEvent.ACTION_DOWN){

            if(event.getEventTime()-lasttime<2000){
                ((MapView)v).getController().zoomInFixing((int)event.getX(), (int)event.getY());                
            }
        }       
        lasttime=event.getEventTime();
        return true;
    }

Being as basic as possible, I cut out all of the code in the OnTouch method and programmed it to simply display a small toast message.

public boolean onTouch(View v, MotionEvent event) {
        if (event.getAction() == MotionEvent.ACTION_DOWN){

               Toast.makeText(this,"Down!",Toast.LENGTH_SHORT).show();

        }       

        return true;
}

This works as expected, displaying the Toast each time the MapView is touched.

I don't understand why the event will fire properly in this case but not in my previous implementation.

Answer

Niranj Patel picture Niranj Patel · Mar 5, 2012

If you are using this method "mapView.setBuiltInZoomControls(true);" then your touch is working at once .

Please remove that that line and check I am sure it will work..

In some case if you want BuiltInZoomControls then you can you OnTouch method of Overlay like as below..

public class MapOverlay extends Overlay {

    public MapOverlay(Context ctx) {super(ctx);}

    @Override
    protected void draw(Canvas c, MapView osmv, boolean shadow) { }

    @Override
    public boolean onTouchEvent(MotionEvent e, MapView mapView) {
        //Write yout touch code here..
        return false;
    }
}