Question

我已经尝试了几个小时来弄清楚为什么我不能在没有这样做的情况下使用Itemized Map叠加层，然后再将其添加到地图的ovelays：

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

如果我尝试在没有MarkerOverlay.addOverlay(overlayitem);命令的情况下执行此操作，那么当我尝试添加新的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，然后我得到一个空的引用exeption（我不知道何时或为什么 - 它说它在调试时没有可用的源代码）

任何想法？

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)

这就是我认为臭名昭着的例外：

   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

我最近遇到过这个问题。这个问题在bug report中列出。

要修复它，您应该在填充任何数据之前调用ItemizedOverlay中的populate（）。我将它添加到构造函数中：

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

逐项加盖需要第二个2个参数，因为它将它们用于点击事件。当您单击其中一个逐项列出的叠加层时，它会有一个标题和与之关联的描述，它们是叠加项中的第二个和第三个参数

Answer 3

如果您对ItemizedOverlay进行重要更改，则每次都有

delete_usrer_Marker_from_Overlays（myitemizedoverlay）;
create_user_Marker（myitemizedoverlay）;
调用MapView.getOverlays（）添加（myitemizedoverlay）。

与

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);
              }                     
          }
        }       
    }

使用ItemizedOverlay导致崩溃的问题

3 个答案: