android在costom arrayadapter java.lang.UnsupportedOperationException中清除
[英]android clear in costom arrayadapter java.lang.UnsupportedOperationException
问题描述
i want to use clear() in my CostomArrayAdapter , but i get always this error:
我想在我的CostomArrayAdapter使用 clear() ，但我总是得到这个错误：
09-08 18:15:01.960: E/AndroidRuntime(27192): FATAL EXCEPTION: main
09-08 18:15:01.960: E/AndroidRuntime(27192): java.lang.UnsupportedOperationException
09-08 18:15:01.960: E/AndroidRuntime(27192): at java.util.AbstractList.remove(AbstractList.java:638)
09-08 18:15:01.960: E/AndroidRuntime(27192): at java.util.AbstractList$SimpleListIterator.remove(AbstractList.java:75)
09-08 18:15:01.960: E/AndroidRuntime(27192): at java.util.AbstractList.removeRange(AbstractList.java:658)
09-08 18:15:01.960: E/AndroidRuntime(27192): at java.util.AbstractList.clear(AbstractList.java:466)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.widget.ArrayAdapter.clear(ArrayAdapter.java:258)
09-08 18:15:01.960: E/AndroidRuntime(27192): at de.fterhorst.pictoriusvertretungsplan.SimpleArrayadapterDay.dayempty(SimpleArrayadapterDay.java:235)
09-08 18:15:01.960: E/AndroidRuntime(27192): at de.fterhorst.pictoriusvertretungsplan.SimpleArrayadapterDay.getView(SimpleArrayadapterDay.java:177)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.widget.AbsListView.obtainView(AbsListView.java:2177)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.widget.ListView.makeAndAddView(ListView.java:1840)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.widget.ListView.fillDown(ListView.java:675)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.widget.ListView.fillFromTop(ListView.java:736)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.widget.ListView.layoutChildren(ListView.java:1655)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.widget.AbsListView.onLayout(AbsListView.java:2012)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.view.View.layout(View.java:14289)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.view.ViewGroup.layout(ViewGroup.java:4559)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.widget.LinearLayout.onLayout(LinearLayout.java:1434)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.view.View.layout(View.java:14289)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.view.ViewGroup.layout(ViewGroup.java:4559)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.view.View.layout(View.java:14289)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.view.ViewGroup.layout(ViewGroup.java:4559)
09-08 18:15:01.960: E/AndroidRuntime(27192): at com.android.internal.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:349)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.view.View.layout(View.java:14289)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.view.ViewGroup.layout(ViewGroup.java:4559)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.view.View.layout(View.java:14289)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.view.ViewGroup.layout(ViewGroup.java:4559)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:1976)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1730)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1004)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5481)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.view.Choreographer.doCallbacks(Choreographer.java:562)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.view.Choreographer.doFrame(Choreographer.java:532)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.os.Handler.handleCallback(Handler.java:730)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.os.Handler.dispatchMessage(Handler.java:92)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.os.Looper.loop(Looper.java:137)
09-08 18:15:01.960: E/AndroidRuntime(27192): at android.app.ActivityThread.main(ActivityThread.java:5103)
09-08 18:15:01.960: E/AndroidRuntime(27192): at java.lang.reflect.Method.invokeNative(Native Method)
09-08 18:15:01.960: E/AndroidRuntime(27192): at java.lang.reflect.Method.invoke(Method.java:525)
09-08 18:15:01.960: E/AndroidRuntime(27192): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
09-08 18:15:01.960: E/AndroidRuntime(27192): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
09-08 18:15:01.960: E/AndroidRuntime(27192): at dalvik.system.NativeStart.main(Native Method)
when i make it so:当我这样做时：
this.clear(); this.clear(); this.notifyDataSetChanged(); this.notifyDataSetChanged();
on my ArrayAdapter :在我的ArrayAdapter ：
public class CostomArrayAdapter extends ArrayAdapter<String>
can i use clear() on a arrayadapter, i hope someone can help me.我可以在阵列适配器上使用 clear() 吗，我希望有人可以帮助我。
4 个解决方案
解决方案1
15 2013-09-08 16:21:54
The error you are getting isn't from calling clear() on the ArrayAdapter .您得到的错误不是在ArrayAdapter上调用clear() 。 You are using a List implementation (possibly the default) which doesn't implement a clear() method and therefore the parent class', ie.您正在使用一个List实现（可能是默认的），它没有实现clear()方法，因此没有实现父类，即。 AbstractList implementation is used, which throws UnsupportedOperationException . AbstractList实现，它抛出UnsupportedOperationException 。
If you pass an array to the constructor如果将数组传递给构造函数
public ArrayAdapter(Context context, int resource, T[] objects) {
init(context, resource, 0, Arrays.asList(objects));
}
it calls Arrays.asList() which returns a List which you cannot add() to, remove() from or clear() .它调用Arrays.asList()它返回一个List ，你可以不add()来， remove()从或clear()
Use this constructor使用这个构造函数
public ArrayAdapter(Context context, int resource, List<T> objects) {
init(context, resource, 0, objects);
}
by passing a LinkedList or ArrayList containing your objects.通过传递包含您的对象的LinkedList或ArrayList 。
解决方案2
3 2013-09-08 16:21:44
If an array is used to initialize and ArrayAdaptor, the array is converted into an AbstractList.如果使用数组初始化和ArrayAdaptor，则将数组转换为AbstractList。 AbstractList does not support remove() or clear() . AbstractList 不支持remove()或clear() 。
You can use a List which exposes a clear.remove, like an ArrayList , instead of an array to initialize.您可以使用一个公开 clear.remove 的List ，如ArrayList ，而不是要初始化的数组。
Edit: To make it clear as suggested, it is not really converted to an AbstractList .编辑：为了按照建议说清楚，它并没有真正转换为AbstractList 。 Its converted to a special ArrayList which extends AbstractList and has no clear/remove methods.它转换为一个特殊的ArrayList ，它扩展了AbstractList并且没有清除/删除方法。
解决方案3
0 2013-09-08 16:27:54
In addition to what Sotirios Delimanolis and rocketboy said, I guess you should fire clear operation on reference of your custom adatper, say for example,除了Sotirios Delimanolis和rocketboy所说的之外，我想您应该根据自定义适配器的参考进行清除操作，例如，
ArrayAdapter<String> adapter = (ArrayAdapter<String>) Listview.getAdapter();
if(adapter!= null)
{
adapter.clear();
adapter.notifyDataSetChanged();
}
解决方案4
0 2020-07-20 21:06:31
in Kotlin, the result of toList() , also does NOT respond to clear() function.在 Kotlin 中， toList()的结果也不响应clear()函数。
You should use toMutableList() when setting your ArrayAdaptor out of another collection or a literal.在将ArrayAdaptor设置为另一个集合或文字时，您应该使用toMutableList() 。
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