Question

所以我想返回我在地图上触摸的任何点的地理位置，但是我的代码在移动/点击屏幕时没有做任何事情。我是Java和Android的新手，所以我认为这与我在java中缺乏编码知识有关。这是我的代码

package sdpd.loc;

import sdpd.loc.createNote.mapOverlay;

import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapView;

import android.os.Bundle;
import android.view.MotionEvent;
import android.widget.Toast;
import android.app.Activity;

public class createNote extends MapActivity {

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

@Override
public void onCreate(Bundle savedInstanceStates){       
    super.onCreate(savedInstanceStates);
    setContentView(R.layout.map);

    MapView mapview=(MapView)findViewById(R.id.MapView);
    mapview.setBuiltInZoomControls(true);


}   


class mapOverlay extends com.google.android.maps.Overlay{
    @Override

    public boolean onTouchEvent(MotionEvent event, MapView mapview){

        if (event.getAction()==1){
            GeoPoint p=mapview.getProjection().fromPixels((int)event.getX(), (int)event.getY());
            Toast.makeText(getBaseContext(),p.getLatitudeE6()/1E6 + "," + p.getLongitudeE6()/1E6, Toast.LENGTH_SHORT).show();

        }
        return false;
    }
}

}

如何让它发挥作用？

Answer 1

您没有将自定义覆盖类mapOverlay（顺便说一句，类名称始终以Java中的大写字母开头）注册到MapView。通过创建类的实例并将其添加到MapView的叠加集合来完成此操作。

您可以通过将以下代码附加到活动的onResume（）方法来执行此操作。

public void onCreate(Bundle savedInstanceStates){       
    super.onCreate(savedInstanceStates);
    setContentView(R.layout.map);

    MapView mapview=(MapView)findViewById(R.id.MapView);
    mapview.setBuiltInZoomControls(true);

    mapOverlay myOverlay = new mapOverlay();
    List<Overlay> overlays = mMapView.getOverlays();        
    overlays.add(myOverlay);
}

现在您的叠加层已注册，并且应处理触摸事件。

Answer 2

public class GoogleMap extends MapActivity {

    MapView mapView; 
    MapController mc;
    GeoPoint p;

    /** Called when the activity is first created. */
    @SuppressWarnings("deprecation")
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        mapView = (MapView) findViewById(R.id.mapview);
        mapView.setStreetView(true);
        LinearLayout zoomLayout = (LinearLayout)findViewById(R.id.zoom);  
        View zoomView = mapView.getZoomControls(); 

        zoomLayout.addView(zoomView, 
            new LinearLayout.LayoutParams(
                LayoutParams.WRAP_CONTENT, 
                LayoutParams.WRAP_CONTENT)); 
        mapView.displayZoomControls(true);

        mc = mapView.getController();
        String coordinates[] = {"23.0504926", "72.528938925"};
        double lat = Double.parseDouble(coordinates[0]);
        double lng = Double.parseDouble(coordinates[1]);

        p = new GeoPoint(
            (int) (lat * 1E6), 
            (int) (lng * 1E6));


        mc.animateTo(p);
        mc.setZoom(17); 

        //---Add a location marker---
        MapOverlay mapOverlay = new MapOverlay();
        List<Overlay> listOfOverlays = mapView.getOverlays();
        listOfOverlays.clear();
        listOfOverlays.add(mapOverlay);        

        mapView.invalidate();
    }

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

    class MapOverlay extends com.google.android.maps.Overlay
    {
        @Override
        public boolean draw(Canvas canvas, MapView mapView, 
        boolean shadow, long when) 
        {
            super.draw(canvas, mapView, shadow);                   

            //---translate the GeoPoint to screen pixels---
            Point screenPts = new Point();
            mapView.getProjection().toPixels(p, screenPts);

            //---add the marker---
            Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.marker);            
            canvas.drawBitmap(bmp, screenPts.x, screenPts.y-50, null);         
            return true;
        }

        ****@Override
        public boolean onTouchEvent(MotionEvent event, MapView mapView) 
        {   
            //---when user lifts his finger---
            if (event.getAction() == 1) {                
                GeoPoint p = mapView.getProjection().fromPixels(
                    (int) event.getX(),
                    (int) event.getY());

                Geocoder geoCoder = new Geocoder(
                    getBaseContext(), Locale.getDefault());
                try {
                    List<Address> addresses = geoCoder.getFromLocation(
                        p.getLatitudeE6()  / 1E6, 
                        p.getLongitudeE6() / 1E6, 1);

                    String add = "";
                    if (addresses.size() > 0) 
                    {
                        for (int i=0; i<addresses.get(0).getMaxAddressLineIndex(); 
                             i++)
                           add += addresses.get(0).getAddressLine(i) + "\n";
                    }

                    Toast.makeText(getBaseContext(), add, Toast.LENGTH_SHORT).show();
                }
                catch (IOException e) {                
                    e.printStackTrace();
                }   
                return true;
            }
            else                
                return false;
        }**        
    }** 
}

向MapView添加触摸事件侦听器

2 个答案: