我正在创建一个具有自定义布局的对话框片段,其中包括一个数字选择器。
为此,我创建了一个DialogFragment类,它实现了NumberPicker.onValueChangeListener和它将使用的布局xml文件。
我在将布局中的数字选择器与片段类中的变量关联时遇到问题,因为'findViewById'"无法解决方法"
我该如何解决这个问题?
以下代码元素:
对话框片段:
public class PlayersDialogueFragment extends DialogFragment implements NumberPicker.OnValueChangeListener {
NumberPicker numberOfPlayersPicker = null;
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
// Use the Builder class for convenient dialog construction
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
LayoutInflater inflater = getActivity().getLayoutInflater();
builder.setView(inflater.inflate(R.layout.players_fragment_layout, null));
numberOfPlayersPicker = (NumberPicker) findViewById(R.id.numberOfPlayersPicker);
numberOfPlayersPicker.setMaxValue(4);
numberOfPlayersPicker.setMinValue(2);
布局-"players_fragment_Layout":
<NumberPicker
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/numberOfPlayersPicker"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
我可以将getActivity()放在findViewById之前,并可以运行该应用程序,但这样做会导致空对象引用错误。
PS:如果重要的话,按下按钮时主活动正在调用对话框片段。
将inflater.inflate(R.layout.players_fragment_layout, null)
分配给变量v
,然后调用v.findViewById
,如下所示:
public class PlayersDialogueFragment extends DialogFragment implements NumberPicker.OnValueChangeListener {
NumberPicker numberOfPlayersPicker = null;
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
// Use the Builder class for convenient dialog construction
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
LayoutInflater inflater = getActivity().getLayoutInflater();
View v = inflater.inflate(R.layout.players_fragment_layout, null);
builder.setView(v);
numberOfPlayersPicker = (NumberPicker) v.findViewById(R.id.numberOfPlayersPicker);
numberOfPlayersPicker.setMaxValue(4);
numberOfPlayersPicker.setMinValue(2);
}
}