MapViewで緯度と経度を取得できませんでしたか？

Question

ここで私はmapviewアクティビティで緯度と経度の値を取得するコードを書いていますが、強制的に閉じてしまうと、これらを取得するための変更や他のメソッドがありますか？

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

    @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); 
    } 
     protected boolean onTap(int i) { 
     OverlayItem item=getItem(i); 
     GeoPoint geo=item.getPoint(); 
     Point pt=map.getProjection().toPixels(geo, null); 
     String message=String.format("Lat: %f | Lon: %f\nX: %d | Y %d", 
     geo.getLatitudeE6()/1000000.0, 
     geo.getLongitudeE6()/1000000.0, 
     pt.x, pt.y); 
     Toast.makeText(getApplicationContext(), 
     message, 
     Toast.LENGTH_LONG).show(); 
     return(true); 
     } 
    private OverlayItem getItem(int i) { 
     // TODO Auto-generated method stub 
     return null; 
    } 


} 

ここで、これは私はあなたがここでやろうとしている内容を正確に把握していないが、私はいくつかのエラーを見ることができます...

12-22 14:50:33.912: D/ddm-heap(834): Got feature list request 
12-22 14:50:34.252: E/ActivityThread(834): Failed to find provider info for com.google.settings 
12-22 14:50:34.271: E/ActivityThread(834): Failed to find provider info for com.google.settings 
12-22 14:50:34.352: E/ActivityThread(834): Failed to find provider info for com.google.settings 
12-22 14:50:34.802: D/AndroidRuntime(834): Shutting down VM 
12-22 14:50:34.812: W/dalvikvm(834): threadid=3: thread exiting with uncaught exception (group=0x4001b188) 
12-22 14:50:34.812: E/AndroidRuntime(834): Uncaught handler: thread main exiting due to uncaught exception 
12-22 14:50:34.841: E/AndroidRuntime(834): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.emigostec/com.emigostec.GmapviewActivity}: java.lang.NullPointerException 
12-22 14:50:34.841: E/AndroidRuntime(834): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496) 
12-22 14:50:34.841: E/AndroidRuntime(834): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512) 
12-22 14:50:34.841: E/AndroidRuntime(834): at android.app.ActivityThread.access$2200(ActivityThread.java:119) 
12-22 14:50:34.841: E/AndroidRuntime(834): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863) 
12-22 14:50:34.841: E/AndroidRuntime(834): at android.os.Handler.dispatchMessage(Handler.java:99) 
12-22 14:50:34.841: E/AndroidRuntime(834): at android.os.Looper.loop(Looper.java:123) 
12-22 14:50:34.841: E/AndroidRuntime(834): at android.app.ActivityThread.main(ActivityThread.java:4363) 
12-22 14:50:34.841: E/AndroidRuntime(834): at java.lang.reflect.Method.invokeNative(Native Method) 
12-22 14:50:34.841: E/AndroidRuntime(834): at java.lang.reflect.Method.invoke(Method.java:521) 
12-22 14:50:34.841: E/AndroidRuntime(834): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) 
12-22 14:50:34.841: E/AndroidRuntime(834): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 
12-22 14:50:34.841: E/AndroidRuntime(834): at dalvik.system.NativeStart.main(Native Method) 
12-22 14:50:34.841: E/AndroidRuntime(834): Caused by: java.lang.NullPointerException 
12-22 14:50:34.841: E/AndroidRuntime(834): at com.emigostec.GmapviewActivity.onCreate(GmapviewActivity.java:24) 
12-22 14:50:34.841: E/AndroidRuntime(834): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
12-22 14:50:34.841: E/AndroidRuntime(834): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459) 
12-22 14:50:34.841: E/AndroidRuntime(834): ... 11 more 
12-22 14:50:34.872: I/dalvikvm(834): threadid=7: reacting to signal 3 
12-22 14:50:35.123: W/dalvikvm(834): threadid=7: spin on suspend #0 threadid=17 (h=1283560) 
12-22 14:50:35.123: W/dalvikvm(834): dumping state: process - 834 
12-22 14:50:35.123: I/dalvikvm(834): "Signal Catcher" daemon prio=5 tid=7 RUNNABLE 
12-22 14:50:35.123: I/dalvikvm(834): | group="system" sCount=0 dsCount=0 s=N obj=0x44bf51e8 self=0x133828 
12-22 14:50:35.123: I/dalvikvm(834): | sysTid=837 nice=0 sched=0/0 cgrp=default handle=1238520 
12-22 14:50:35.123: I/dalvikvm(834): at dalvik.system.NativeStart.run(Native Method) 
12-22 14:50:35.123: I/dalvikvm(834): "TrafficService" prio=1 tid=17 RUNNABLE 
12-22 14:50:35.123: I/dalvikvm(834): | group="main" sCount=1 dsCount=0 s=N obj=0x44c184b8 self=0x11ec98 
12-22 14:50:35.123: I/dalvikvm(834): | sysTid=842 nice=19 sched=0/0 cgrp=bg_non_interactive handle=1283560 
12-22 14:50:35.123: I/dalvikvm(834): DumpRunning: Thread at 0x11ec98 has no curFrame (threadid=17) 
12-22 14:50:35.162: W/dalvikvm(834): threadid=7: spin on suspend resolved in 293 msec 
12-22 14:50:35.321: I/dalvikvm(834): Wrote stack trace to '/data/anr/traces.txt' 

Answer 1

上記のコードのための私のLogCatです：

• クラス宣言が間違っている（あなたがMapActivityない活動を使用する必要があります）：

あなたがある場合

GeoPoint gp= new GeoPoint((int)(26.2*1.0E6), (int)(52.6*1.0E6)); 

：

パブリッククラスGpsoverlayActivityはGPについてMapActivity

• を拡張し、あなたはこのように任意の緯度と経度を挿入し、それに値を入れていませんマップ上にマーカーを追加しようとしています。次の構造を持つ別のクラスを作成することをお勧めします。

  public class MapViewItemizedOverlay extends ItemizedOverlay { 
  
      private ArrayList<OverlayItem> mOverlays = new ArrayList<OverlayItem>(); 
      private Context mContext; 
  
      public MapViewItemizedOverlay(Drawable defaultMarker, Context context) { 
       super(boundCenterBottom(defaultMarker)); 
       // TODO Auto-generated constructor stub 
       mContext = context; 
      } 
  
      @Override 
      protected OverlayItem createItem(int i) { 
       return mOverlays.get(i); 
      } 
  
  
      @Override 
      public int size() { 
       // TODO Auto-generated method stub 
       return mOverlays.size(); 
      } 
  
      public void addOverlay(OverlayItem overlay) { 
       mOverlays.add(overlay); 
       populate(); 
      } 
  
  
      @Override 
      public boolean onTap(int index) 
      { 
       //get the marker on the map from here 
       OverlayItem item = mOverlays.get(index); 
       OverlayItem item=getItem(i); 
       GeoPoint geo=item.getPoint(); 
       Point pt=map.getProjection().toPixels(geo, null); 
       String message=String.format("Lat: %f | Lon: %f\nX: %d | Y %d", 
       geo.getLatitudeE6()/1000000.0, 
       geo.getLongitudeE6()/1000000.0, 
       pt.x, pt.y); 
       Toast.makeText(getApplicationContext(), 
       message, 
       Toast.LENGTH_LONG).show(); 
      return true; 
      } 
  

  とMapActivityでこのようにそれを使用する：あなたがクラッシュ関連の質問を投稿すると、あまりにもあなたのlogcat出力を投稿してください

  MapView mapView = (MapView) findViewById(R.id.mapview); 
  MapController mc = mapView.getController(); 
  List<Overlay> mapOverlays = mapView.getOverlays(); 
  //add any icon here for the marker 
  Drawable drawable = MainActivity.this.getResources().getDrawable(R.drawable.icon); 
  MapViewItemizedOverlay itemizedOverlay = new MapViewItemizedOverlay(drawable,this); 
  //insert any lat and lng as integers here 
  GeoPoint point1 = new GeoPoint(lat,lng); 
  OverlayItem overlayitem1 = new OverlayItem(point1, "Info", "You are here!"); 
  itemizedOverlay.addOverlay(overlayitem1); 
  mapOverlays.add(itemizedOverlay); 
  mc.animateTo(point1);