Android: ItemizedOverlay onTouchEvent and onTap overlapping

问题

I am trying to place a marker on a map overlay and then present a dialog when the user selects the drawable. The problem is the events seem to overlap. After I click the map and the marker is drawn, the onTap fires immediately afterwards, and because I have just drawn the marker, it is directly under the onTap event, so my dialog always fires. Does anyone have any suggestions on how to make these events mutually exclusive?

Here is the code for the map activity:

public class SelectGameLocation extends MapActivity implements GestureDetector.OnGestureListener, GestureDetector.OnDoubleTapListener  {

    private MapView mapView = null;
    private SelectGameLocationItemizedOverlay selectLocationOverlay = null;
    private List<Overlay> mapOverlays = null;
    private GestureDetector gestureDetector = null;

    @Override
    protected void onCreate(Bundle arg0) {
        super.onCreate(arg0);

        //set the layout
        setContentView(R.layout.activity_select_game_location);

        //configure activity for double clicks
        gestureDetector = new GestureDetector(this);
        gestureDetector.setOnDoubleTapListener(this);

        //create and configure mapview
        mapView = (MapView) findViewById(R.id.selectGameLocation);
        mapView.setBuiltInZoomControls(true);
        mapView.setHapticFeedbackEnabled(true);

        //configure the overlay to draw the icons on the map
        mapOverlays = mapView.getOverlays();
        Drawable drawable = this.getResources().getDrawable(R.drawable.map_icon);
        selectLocationOverlay = new SelectGameLocationItemizedOverlay(drawable, this);
        mapOverlays.add(selectLocationOverlay);
    }

    @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
        gestureDetector.onTouchEvent(ev);
        return super.dispatchTouchEvent(ev);
    }

    @Override
    public boolean onDoubleTap(MotionEvent me) {
        GeoPoint p = GeoPointHelper.getPointClicked(me, mapView);
        mapView.getController().animateTo(p);
        mapView.getController().zoomIn();
        return true;
    }

    //Overridden methods but not used
    @Override
    public boolean onDoubleTapEvent(MotionEvent me) {
        return false;
    }

    @Override
    public boolean onDown(MotionEvent me) {
        return false;
    }

    @Override
    protected boolean isRouteDisplayed() {
        return false;
    }

    @Override
    public void onShowPress(MotionEvent e) {
    }

    @Override
    public boolean onSingleTapConfirmed(MotionEvent me) {
        return false;
    }

    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
        return false;
    }

    @Override
    public void onLongPress(MotionEvent e) {
    }

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
        return false;
    }

    @Override
    public boolean onSingleTapUp(MotionEvent me) {
        return false;
    }
}

and the code for the overlay class:

public class SelectGameLocationItemizedOverlay extends ItemizedOverlay {

    private Context context = null;
    private List<OverlayItem> overlays = new ArrayList<OverlayItem>();

    public SelectGameLocationItemizedOverlay(Drawable marker, Context context) {
        super(boundCenterBottom(marker));
        this.context = context;
    }

    @Override
    protected boolean onTap(int index) {

        OverlayItem itemClicked = overlays.get(index);
        AlertDialog.Builder dialog = new AlertDialog.Builder(context);
        dialog.setTitle(itemClicked.getTitle());
        dialog.setMessage(itemClicked.getSnippet());
        dialog.setCancelable(true);
        dialog.setPositiveButton(R.string.yes, new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                Log.i(this.getClass().getName(), "Selected Yes To Add Location");
                ((SelectGameLocation) context).finish();
            }
        });
        dialog.setNegativeButton(R.string.no, new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                Log.i(this.getClass().getName(), "Selected No To Add Location");
                dialog.cancel();
            }
        });
        dialog.show();
        return true;
    }

    @Override
    public boolean onTouchEvent(MotionEvent me, MapView mapView) {
        drawMarker(GeoPointHelper.getPointClicked(me, mapView));
        return super.onTouchEvent(me, mapView);
    }

    private OverlayItem drawMarker(GeoPoint p) {        
            OverlayItem overlayitem = new OverlayItem(p, "Select As Game Location?", "Do you want this location to be added as the location for the game?");
            getOverlays().clear();
            addOverlay(overlayitem);
            return overlayitem;
    }

    public List<OverlayItem> getOverlays() {
        return overlays;
    }

    public void addOverlay(OverlayItem overlay) {
        overlays.add(overlay);
        populate();
    }

    @Override
    protected OverlayItem createItem(int i) {
        return overlays.get(i);
    }

    @Override
    public int size() {
        return overlays.size();
    }

}

回答1:

I had exactly the same issue, my onTouchEvent added a marker to a map, and wanted it to show information about that marker when the user clicks on it, it worked but it also added another marker on top of it.

So what I did was not use onTouchEvent but do everything in onTap(int index) and onTap(Geopoint p, MapView mapView) like so:

public boolean onTap (final GeoPoint p, final MapView mapView){
    boolean tapped = super.onTap(p, mapView);
    if (tapped){            
        //do what you want to do when you hit an item           
    }           
    else{
        //do what you want to do when you DON'T hit an item
        }                   
    return true;
}

//Return true in order to say that the listener has correctly taken the event into account 
@Override
protected boolean onTap(int index) {
    return true;
}

Regards,

Tom

回答2:

If you are updating the previous overlay, set isFirst=true; in the call to `remove() to remove the overlay in question.

In the onTap() call, use

if(isFirst)
{
    isFirst=false;
} else{
    // the actual onTap() comes here
}

I hope that it'll work the same if isFirst=true is set in the onDraw() as well.

回答3:

I think that the problem is fundamentally that the onTap is a particular onTouchEvent, so if you write both in the overlay they are both fired when you touch the map

You could try to add a new overlay item in one of the touch events you implemented in your mapActivity and leave the onTap event in the overlay as it is right now

it might work this way but you have to try, I'm not sure!

来源：https://stackoverflow.com/questions/4971749/android-itemizedoverlay-ontouchevent-and-ontap-overlapping