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.
See Question&Answers more detail:
os 与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…