Android 如何获取MapView的左上角和右下角经度和纬度值

这是我的代码，我正在尝试显示坐标，这里我在寻找左上角和右下角的长纬度值，但它不起作用。任何人建议我进行任何修改或任何其他方法来获取坐标

    public class GpsoverlayActivity extends MapActivity {
        /** Called when the activity is first created. */
        MapView map;
        MapController mc;
        GeoPoint gp;
        //Projection projection ;

        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);
            map=(MapView)findViewById(R.id.mapView);
           mc=map.getController();
           mc.setCenter(gp);
            mc.setZoom(20);
            Projection proj = map.getProjection();
            GeoPoint topLeft = proj.fromPixels(0, 0);

            GeoPoint bottomRight = proj.fromPixels(map.getWidth()-1, map.getHeight()-1);

            Double topLat = topLeft.getLatitudeE6()/1E6;
            Double topLon = topLeft.getLongitudeE6()/1E6;
            Double bottomLat = bottomRight.getLatitudeE6()/1E6;
            Double bottomLon = bottomRight.getLongitudeE6()/1E6;

        }
 @Override
    protected void onResume() {
        // TODO Auto-generated method stub
        super.onResume();
        myLocationOverlay.enableMyLocation();
    }
    @Override
    protected void onPause() {
        // TODO Auto-generated method stub
        super.onPause();
        myLocationOverlay.disableMyLocation();
    }

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

这是我的日志

12-23 11:26:50.264: W/dalvikvm(390): Unable to resolve superclass of Lcom/gpsoverlay/emigos/GpsoverlayActivity; (6)
12-23 11:26:50.264: W/dalvikvm(390): Link of class 'Lcom/gpsoverlay/emigos/GpsoverlayActivity;' failed
12-23 11:26:50.275: D/AndroidRuntime(390): Shutting down VM
12-23 11:26:50.285: W/dalvikvm(390): threadid=3: thread exiting with uncaught exception (group=0x4001b188)
12-23 11:26:50.285: E/AndroidRuntime(390): Uncaught handler: thread main exiting due to uncaught exception
12-23 11:26:50.456: E/AndroidRuntime(390): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.gpsoverlay.emigos/com.gpsoverlay.emigos.GpsoverlayActivity}: java.lang.ClassNotFoundException: com.gpsoverlay.emigos.GpsoverlayActivity in loader dalvik.system.PathClassLoader@44e83900
12-23 11:26:50.456: E/AndroidRuntime(390):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2417)
12-23 11:26:50.456: E/AndroidRuntime(390):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
12-23 11:26:50.456: E/AndroidRuntime(390):  at android.app.ActivityThread.access$2200(ActivityThread.java:119)
12-23 11:26:50.456: E/AndroidRuntime(390):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
12-23 11:26:50.456: E/AndroidRuntime(390):  at android.os.Handler.dispatchMessage(Handler.java:99)
12-23 11:26:50.456: E/AndroidRuntime(390):  at android.os.Looper.loop(Looper.java:123)
12-23 11:26:50.456: E/AndroidRuntime(390):  at android.app.ActivityThread.main(ActivityThread.java:4363)
12-23 11:26:50.456: E/AndroidRuntime(390):  at java.lang.reflect.Method.invokeNative(Native Method)
12-23 11:26:50.456: E/AndroidRuntime(390):  at java.lang.reflect.Method.invoke(Method.java:521)
12-23 11:26:50.456: E/AndroidRuntime(390):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
12-23 11:26:50.456: E/AndroidRuntime(390):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
12-23 11:26:50.456: E/AndroidRuntime(390):  at dalvik.system.NativeStart.main(Native Method)
12-23 11:26:50.456: E/AndroidRuntime(390): Caused by: java.lang.ClassNotFoundException: com.gpsoverlay.emigos.GpsoverlayActivity in loader dalvik.system.PathClassLoader@44e83900
12-23 11:26:50.456: E/AndroidRuntime(390):  at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:243)
12-23 11:26:50.456: E/AndroidRuntime(390):  at java.lang.ClassLoader.loadClass(ClassLoader.java:573)
12-23 11:26:50.456: E/AndroidRuntime(390):  at java.lang.ClassLoader.loadClass(ClassLoader.java:532)
12-23 11:26:50.456: E/AndroidRuntime(390):  at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
12-23 11:26:50.456: E/AndroidRuntime(390):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2409)
12-23 11:26:50.456: E/AndroidRuntime(390):  ... 11 more
12-23 11:26:50.645: I/dalvikvm(390): threadid=7: reacting to signal 3
12-23 11:26:50.825: I/dalvikvm(390): Wrote stack trace to '/data/anr/traces.txt'
12-23 11:26:54.515: I/Process(390): Sending signal. PID: 390 SIG: 9

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您需要扩展MapActivity而不是Activity。map的所有类和接口都可在MapActivity中使用，MapView仅在MapActivity中工作

在覆盖初始化之后，您正在使用mapv对象，我没有找到这个

myLocationOverlay = new MyLocationOverlay(this, mapv); // here mapv object used instead of map I think
mapv.getOverlays().add(myLocationOverlay);
mapv.postInvalidate(); 

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是的……我试过了，这里我使用oly one活动作为Mapactivity，但我需要lang&Lattude值显示在o/pI中。我认为你走错了方向，因为你得到了右下角的值，它将为你提供地图控件的宽度和高度，我认为你需要从地图中绑定地图实际显示的值，就像当前区域一样