ItemizedOverlay崩溃的问题

Question

我已经尝试了几个小时，试图弄清楚为什么我不能在不这样做的情况下使用分项地图覆盖，然后再将其添加到地图的ovelays中：

GeoPoint point; OverlayItem overlayitem = new OverlayItem(point, "",""); MarkerOverlay.addOverlay(overlayitem);

如果我尝试在不使用MarkerOverlay.addOverlay(overlayitem);命令的情况下执行此操作，则当我尝试添加新的overLay时，如下所示：

public boolean onTap(GeoPoint point, MapView mapView)
{
    if (mOverlays.size() > 0)
        mOverlays.remove(0);
    OverlayItem overlayitem = new OverlayItem(point, "", "");
    mOverlays.add(overlay);
    populate();
    return true;
}

在我的ItemizedOverlay类中，我只是得到了一个空引用exeption (我不知道什么时候或者为什么-它说在调试时没有源代码)

有什么想法吗？

编辑:这是我在logcat中可以找到的：

09-20 22:36:22.164: WARN/dalvikvm(311): threadid=3: thread exiting with uncaught exception (group=0x4001b188)

这就是我认为的臭名昭著的例外：

   09-20 22:36:22.293: ERROR/AndroidRuntime(311): java.lang.NullPointerException
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at com.google.android.maps.ItemizedOverlay.getItemsAtLocation(ItemizedOverlay.java:617)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at com.google.android.maps.ItemizedOverlay.getItemAtLocation(ItemizedOverlay.java:586)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at com.google.android.maps.ItemizedOverlay.handleMotionEvent(ItemizedOverlay.java:498)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at com.google.android.maps.ItemizedOverlay.onTouchEvent(ItemizedOverlay.java:572)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at com.google.android.maps.OverlayBundle.onTouchEvent(OverlayBundle.java:63)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at com.google.android.maps.MapView.onTouchEvent(MapView.java:625)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at android.view.View.dispatchTouchEvent(View.java:3709)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:852)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:822)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:822)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:822)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1659)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1107)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at android.app.Activity.dispatchTouchEvent(Activity.java:2061)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1643)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1691)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at android.os.Handler.dispatchMessage(Handler.java:99)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at android.os.Looper.loop(Looper.java:123)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at android.app.ActivityThread.main(ActivityThread.java:4363)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at java.lang.reflect.Method.invokeNative(Native Method)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at java.lang.reflect.Method.invoke(Method.java:521)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
09-20 22:36:22.293: ERROR/AndroidRuntime(311):     at dalvik.system.NativeStart.main(Native Method)
09-20 22:36:22.394: ERROR/dalvikvm(311): Unable to open stack trace file '/data/anr/traces.txt': Permission denied

Answer 1

我最近遇到了这个问题。此bug report中概述了该问题。

要解决这个问题，应该在填充任何数据之前在ItemizedOverlay中调用populate()。我将其添加到构造函数中：

private class MyItemizedOverlay extends ItemizedOverlay<OverlayItem> {

    private Context context;
    private ArrayList<OverlayItem> mOverlays = new ArrayList<OverlayItem>();

    LocationItemizedOverlay(Drawable defaultMarker, Context context) {
        super(boundCenterBottom(defaultMarker));
        this.context = context;
        populate(); // Add this
    }
}

Answer 2

分项覆盖需要第二个2个参数，因为它将它们用于单击事件。单击其中一个逐项叠加时，它将具有与之关联的标题和描述，这是叠加项目中的第2个和第3个参数

Answer 3

如果你在你的ItemizedOverlay上做了重要的改变，你有很多时间去做

1. delete_usrer_Marker_from_Overlays(myitemizedoverlay);
2. create_user_Marker(myitemizedoverlay)；
3. mapView.getOverlays().add(myitemizedoverlay)；

使用

private void delete_usrer_Marker_from_Overlays(MyOverlays myio){

    List<Overlay> mapOverlays = mapView.getOverlays();
    if (mapOverlays != null) 
        {
          for (int i = 0;i< mapOverlays.size();i++)
          {
              Overlay x = mapOverlays.get(i);
              if (x.hashCode() == myio.hashCode())
              {
                  mapOverlays.remove(x);
              }                     
          }
        }       
    }