问题
fellas
I am facing very strange issue from many days. I am trying to update overlay frequently. So sometime I am getting "java.util.ConcurrentModificationException" when I touch on map or sometime getting when map trying to update overlay But I am not finding perfect line which on this error is coming.
02-17 14:56:01.621: W/dalvikvm(3653): threadid=1: thread exiting with uncaught exception (group=0x40015560)
02-17 14:56:01.631: E/AndroidRuntime(3653): FATAL EXCEPTION: main
02-17 14:56:01.631: E/AndroidRuntime(3653): java.util.ConcurrentModificationException
02-17 14:56:01.631: E/AndroidRuntime(3653): at java.util.ArrayList$ArrayListIterator.next(ArrayList.java:576)
02-17 14:56:01.631: E/AndroidRuntime(3653): at com.google.android.maps.OverlayBundle.draw(OverlayBundle.java:41)
02-17 14:56:01.631: E/AndroidRuntime(3653): at com.google.android.maps.MapView.onDraw(MapView.java:530)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.view.View.draw(View.java:6880)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.view.ViewGroup.drawChild(ViewGroup.java:1646)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1373)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.view.ViewGroup.drawChild(ViewGroup.java:1644)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1373)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.view.View.draw(View.java:6883)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.widget.FrameLayout.draw(FrameLayout.java:357)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.view.ViewGroup.drawChild(ViewGroup.java:1646)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1373)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.view.View.draw(View.java:6883)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.widget.FrameLayout.draw(FrameLayout.java:357)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.view.ViewGroup.drawChild(ViewGroup.java:1646)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1373)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.view.View.draw(View.java:6883)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.widget.FrameLayout.draw(FrameLayout.java:357)
02-17 14:56:01.631: E/AndroidRuntime(3653): at com.android.internal.policy.impl.PhoneWindow$DecorView.draw(PhoneWindow.java:1862)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.view.ViewRoot.draw(ViewRoot.java:1522)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.view.ViewRoot.performTraversals(ViewRoot.java:1258)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.view.ViewRoot.handleMessage(ViewRoot.java:1859)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.os.Handler.dispatchMessage(Handler.java:99)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.os.Looper.loop(Looper.java:130)
02-17 14:56:01.631: E/AndroidRuntime(3653): at android.app.ActivityThread.main(ActivityThread.java:3683)
02-17 14:56:01.631: E/AndroidRuntime(3653): at java.lang.reflect.Method.invokeNative(Native Method)
02-17 14:56:01.631: E/AndroidRuntime(3653): at java.lang.reflect.Method.invoke(Method.java:507)
02-17 14:56:01.631: E/AndroidRuntime(3653): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
02-17 14:56:01.631: E/AndroidRuntime(3653): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
02-17 14:56:01.631: E/AndroidRuntime(3653): at dalvik.system.NativeStart.main(Native Method)
I am using Balloon Overlay
I think it is throwing error on "mapview.getOverlay()" because it is calling 4-5 times in 1 seconds..
Thanks,
CapDroid
here is code flow.. My Thread code....
Thread connection = new Thread(){
public void run() {
try {
while (my condition)
{
try
{
//This method should be call every seconds
updateMethod();
}
catch (Exception e)
{
e.printStackTrace();
break;
}
}
}
catch (Exception e)
{
}
}
};
Here is My updateMethod(); in this code hashmapOverlay is HashMap like as below
public static Map<String,MyItemizedOverlay> hashmapOverlay;
public void updateMethod()
{
if(hashmapOverlay.containsKey(id))
{
mapview.getOverlays().remove(hashmapOnlineFriendsOverlay.get(id));
}
MyItemizedOverlay mMyItemizedOverlay = new MyItemizedOverlay(drawable, mapview);
OverlayItem overlayItem = new OverlayItem(gp,title ,snippet);
mMyItemizedOverlay.addOverlay(overlayItem);
hashmapOverlay.put(id, mMyItemizedOverlay);
addOverlayMethod(mActivity, mapView, mMyItemizedOverlay);
}
Here is my addOverlayMethod
addOverlayMethod(Activity mActivity, final MapView mapView, final Object mObject)
{
mActivity.runOnUiThread(new Runnable(){
@Override
public void run()
{
try {
MyItemizedOverlay overlay = (MyItemizedOverlay) mObject;
mapView.getOverlays().add(overlay);
} catch (Exception e)
{}
}
});
}
回答1:
In order to avoid ConcurrentModificationException simply copy your collection in any of the following cases:
- before iterating over a collection
- before passing it into an API
At first glance, this might seem like overkill but it will save you a lot of headache later on. Copying is simple, just call new ArrayList<YourClass>(existingList).
回答2:
I think You use Thread and its create Concurrency So use Syncronized(MainActivity.this) in Your Run Method....And Use Vector Instead of List Because Vector is Syncronized...Its Works for me...
回答3:
Well, it seems that in your updateMethod() you are still trying to Update your UI from a Non-UI thread by
mapview.getOverlays().remove(hashmapOnlineFriendsOverlay.get(id));
So, try to execute this part of your code inside the RunOnUiThread and try. Hope this would work.
UPDATE:
Also, why you are trying to add and remove your Overlay everything, you don't need to do that just try to update your Overlay and invalidate it. Have a look at this example.
回答4:
I'm not sure about the overlay management, but the way I see it, you're modifying your HashMap with HashMap.put on a non-UI thread (in UpdateMethod), when it's no doubt being iterated over or used elsewhere in the app - probably when still requesting new Overlays as you move your map around.
If you read the docs, it says this will cause a ConcurrentModificationException. Instead, try using a ConcurrentHashMap, or restructure your code to update the hashmap on the main thread where it is being used.
回答5:
ya, you can do a work around, step as follow.
- Make a Pendingnotification class(modication detail).
- Make a list of the Pendingnotification.
- when any notification receive dnt modify it directly, Collect all the modification and put stack(Pendingnotification class) ie. add it in Pendingnotification list.
- now one by one modify the object and remove the same object when its work done.
same way follow untill Pendingnotification List become empty.
And also note that any modification must be perform in UI Thread not in NonUI Thread
来源：https://stackoverflow.com/questions/9326129/java-util-concurrentmodificationexception-on-mapview