0
我有得到我的方法創建的HashMap
ConcurrentModificationException的與ViewTreeObserver onPreDrawLstener
final HashMap<Long, Rect> listViewItemBounds = new HashMap<Long, Rect>();
,節省的可見視圖所有的界限在ListView
for (int i = 0; i < getChildCount(); ++i) {
View child = getChildAt(i);
if(child != null){
int position = firstVisiblePosition+i;
long itemID = adapter.getItemId(position);
Rect startRect = new Rect(child.getLeft(), child.getTop(), child.getRight(),child.getBottom());
listViewItemBounds.put(itemID, startRect);
listViewItemDrawables.put(itemID, getBitmapDrawableFromView(child));
}
}
然後我在ListView控件啓動OnPreDrawListener
final ViewTreeObserver observer = getViewTreeObserver();
observer.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
public boolean onPreDraw() {
.
.
.
}
)};
and in the通過他onPreDrawListener我環路HashMap來獲取已保存的視圖邊界
for (Long itemId: listViewItemBounds.keySet()) { //points here
.
.
.
istViewItemBounds.remove(itemId);
}
當我改變/更新,其中這一切都被一次onPreDraw
稱爲當前通過HashMap的循環,而它正在更新適配器問題就來了再次由於適配器的變化。
那麼我該如何防止這裏的併發,所以我沒有得到ConcurrentModificationException
?
堆棧跟蹤:
08-31 19:09:41.398 29127-29127/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.util.ConcurrentModificationException
at java.util.HashMap$HashIterator.nextEntry(HashMap.java:792)
at java.util.HashMap$KeyIterator.next(HashMap.java:819)
at com.tyczj.myapp.views.HeaderGridView$3.onPreDraw(HeaderGridView.java:511)
at android.view.ViewTreeObserver.dispatchOnPreDraw(ViewTreeObserver.java:680)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1842)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:989)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4351)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
at android.view.Choreographer.doCallbacks(Choreographer.java:562)
at android.view.Choreographer.doFrame(Choreographer.java:532)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
at android.os.Handler.handleCallback(Handler.java:725)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)
編輯:
Iterator<Long> it = listViewItemBounds.keySet().iterator();
while(it.hasNext()){
long itemId = it.next(); //error
}
你是對的,我沒有。 Mea culpa沒有看到remove()調用。 – 2014-09-01 00:04:59
不用擔心。我第一次嘗試回答這個問題並不完全清楚 - 我試圖在移動設備上輸入代碼,但獲得的成功有限。 – 2014-09-01 00:12:27
ok看到我的編輯,我改變了使用'Iterator',但現在我得到'it.next()'的錯誤,我錯過了什麼? – tyczj 2014-09-01 00:15:22