android - ItemizedOverlay 的崩溃问题

Question

我已经尝试了几个小时来弄清楚为什么在将逐项 map 覆盖添加到 map 的覆盖之前，我不能不这样做就不能使用它:

GeoPoint 点；
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，那么当我尝试像这样添加新的覆盖时:

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，我只是得到一个空引用异常(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)

有什么想法吗？

编辑:这是我可以在 logcat 中找到的:

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著的异常(exception):

   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。 .

要修复它，您应该在填充任何数据之前在 ItemizedOverlay 中调用 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
    }
}