我想显示一个toast消息,如果我在onCreate()中这样做,它会正常工作。但是我想像这样做,然后我收到了一个错误信息:
Java.Lang.NullPointerException: 尝试调用虚拟方法“android.content.res.Resources android.content.Context.getResources()”时出现空对象引用
应该怎么办?
Java.Lang.NullPointerException: 尝试调用虚拟方法“android.content.res.Resources android.content.Context.getResources()”时出现空对象引用
应该怎么办?
public void textToast(string textToDisplay) {
Toast.MakeText(this,
textToDisplay, ToastLength.Long).Show();
}
class SampleTabFragment : Fragment
{
Button add;
MainActivity main = new MainActivity();
public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
base.OnCreateView(inflater, container, savedInstanceState);
var view = inflater.Inflate(Resource.Layout.Tab, container, false);
add = view.FindViewById<Button>(Resource.Id.add);
add.Click += Click;
return view;
}
void Click(object sender, EventArgs eventArgs)
{
main.textToast( "I like Toast!");
}
}
onAttach()
方法中使用getActivity()
来确保它是正确的引用。 - Jon Douglas