Android Spinner 在 Botttomsheet 对话框中返回 NullPointerException

Question

我正在尝试 Return 我的 BottomSheet 中的微调值 Dialog.But 它正在返回 NullPointerException always.Below 是我的 String.XML 文件

 <string-array name="e_type">
    <item>item1</item>
    <item>item2</item>
</string-array>

这是我的 bottomsheet_activity.xml 文件

  <Spinner
    android:id="@+id/spinner"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:entries="@array/e_type" />

我正在尝试通过以下代码获取值

final BottomSheetDialog dialog3 = new BottomSheetDialog(MainActivity.this);
dialog3.setContentView(R.layout.bottomsheet_activity);

final Spinner spinner=(Spinner) findViewById(R.id.spinner);
final String itemText = (String) spinner.getSelectedItem();

String requesttype=itemText; //Trying to use this variable but returning null

dialog3.show();

为什么返回 null ，我不知道

Answer 1

您的微调器为空，因为您是从 activity 的 xml 文件中找到它的。试试下面的代码，

final BottomSheetDialog dialog3 = new BottomSheetDialog(MainActivity.this);
View mDialogView = LayoutInflater.from(this).inflate(R.layout.activity_mine, null)
dialog3.setContentView(mDialogView);

final Spinner spinner=(Spinner) mDialogView.findViewById(R.id.spinner);
final String itemText = (String) spinner.getSelectedItem();

String requesttype=itemText; //Trying to use this variable but returning null

dialog3.show();

希望对您有所帮助！！

Answer 2

希望这对你有用。

String requesttype;

 @Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    final BottomSheetDialog dialog3 = new BottomSheetDialog(NewActivity.this);
    dialog3.setContentView(R.layout.lay_new);

    final Spinner spinner=(Spinner) dialog3.findViewById(R.id.spinner);

    spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
            requesttype=parent.getItemAtPosition(position).toString();
            Log.e("requesttype",requesttype);
        }

        @Override
        public void onNothingSelected(AdapterView<?> parent) {

        }
    });

    dialog3.show();
}

Answer 3

您正在从

中获取参考

final BottomSheetDialog dialog3 = new BottomSheetDialog(MainActivity.this);
dialog3.setContentView(R.layout.bottomsheet_activity);

所以改变这个-:

final Spinner spinner=(Spinner) findViewById(R.id.spinner);
final String itemText = (String) spinner.getSelectedItem();

到-:

final Spinner spinner=(Spinner) dialog3.findViewById(R.id.spinner);
final String itemText = (String) spinner.getSelectedItem();

Android Spinner 在 Botttomsheet 对话框中返回 NullPointerException

Android Spinner is Returning NullPointerException in Botttomsheet Dialog

android

android-spinner

android-bottomsheetdialog