安卓clear in costom arrayadapter java.lang.UnsupportedOperationException
安卓clear in costom arrayadapter java.lang.UnsupportedOperationException
提问于 2013-09-09 00:18:14
我想在我的CostomArrayAdapter中使用clear()，但我总是得到这样的错误：
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)当我这样做的时候：
this.clear()；this.notifyDataSetChanged()；
在我的ArrayAdapter
public class CostomArrayAdapter extends ArrayAdapter<String>我可以在arrayadapter上使用clear()吗，我希望有人能帮我。
回答 4
Stack Overflow用户
发布于 2013-09-09 00:21:55
您得到的错误不是因为在ArrayAdapter上调用clear()。你正在使用一个没有实现clear()方法的List实现(可能是默认的)，因此也就是父类。使用抛出UnsupportedOperationException的AbstractList实现。
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));
}它调用Arrays.asList()，返回一个你不能add()到的List，remove()或者clear()。
使用此构造函数
public ArrayAdapter(Context context, int resource, List<T> objects) {
init(context, resource, 0, objects);
}通过传递包含您的对象的LinkedList或ArrayList。
Stack Overflow用户
发布于 2013-09-09 00:21:45
如果数组用于初始化和ArrayAdaptor，则该数组将转换为AbstractList。AbstractList不支持remove()或clear()。
您可以使用公开clear.remove的List (如ArrayList )而不是数组进行初始化。
编辑:按照建议，它并没有真正转换为AbstractList。它被转换成一个特殊的 ArrayList，它扩展了AbstractList，没有清除/删除方法。
Stack Overflow用户
发布于 2013-09-09 00:27:54
除了Sotirios Delimanolis和rocketboy所说之外，我猜您应该在自定义adatper的引用上触发清除操作，例如，
ArrayAdapter<String> adapter = (ArrayAdapter<String>) Listview.getAdapter();
if(adapter!= null)
{
adapter.clear();
adapter.notifyDataSetChanged();
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/18685898
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