我如何獲得左上角和右下角經度和緯度值爲我的MapView

Question

這是我的代碼我試圖讓座標顯示，在這裏我正在尋找左上角和右下角的長&緯度值，但它的不工作的任何一個建議我任何修改或以其他方式取得的座標..

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; 
    } 
    } 

在這裏，這是我的logcat

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 

Answer 1

你需要延長的，而不是活動MapActivity。 MapActivity中的所有類和接口都可以在MapActivity和MapView中使用。

覆蓋初始化後，您使用的是mapv對象，我沒有找到這個。

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