Question

我有一个在片段中成功启动的DatePickerDialog。当方向发生变化时，应用程序崩溃。 logcat输出表明NPE与DatePickerFragment中的onDismiss一起发生。 onDismiss代码用于切换软键盘再次显示（在启动DatePickerDialog后将其切换）。当我删除onDismiss代码时，应用程序不再崩溃。我在这里缺少什么？

这是部分DatePickerFragement文件：

public class DatePickerFragment extends DialogFragment implements DatePickerDialog.OnDateSetListener {

public DatePickerFragment() {
}

@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
...
DatePickerDialog picker = new DatePickerDialog(getActivity(),
        this, year, month, day);
return picker;
}


public void onDismiss(final DialogInterface dialog) {
InputMethodManager imm = (InputMethodManager) getActivity().getSystemService(CardViewActivity.INPUT_METHOD_SERVICE);
imm.toggleSoftInput(InputMethodManager.SHOW_IMPLICIT, 0);
super.onDismiss(dialog);
}

}

这是我有另一个处理方向更改的片段，没有崩溃和键盘切换正确：

public class CreateSkycardFragment extends DialogFragment {

public CreateSkycardFragment() {
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.skyfrag_layout, container, false);
    getDialog().setTitle("Delete card");


    Button btnCancel = (Button) rootView.findViewById(R.id.btnCancel);
    btnCancel.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            InputMethodManager imm = (InputMethodManager) getActivity().getSystemService(CardViewActivity.INPUT_METHOD_SERVICE);
            // The soft keyboard always closes when the DialogFragment is displayed.  So the
            // line below toggles the soft keyboard to show again.
            imm.toggleSoftInput(InputMethodManager.SHOW_IMPLICIT, 0);
            // The line below cancels the dialog box.
            getDialog().cancel();
        }
    });

    // When the user clicks "OK" to delete for the "Delete skycard" dialog.
    Button btnOK = (Button) rootView.findViewById(R.id.btnOK);
    btnOK.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // Next line dismisses the DialogFragment
            dismiss();
            // Next line returns to the previous activity (MainActivity) by closing
            // the current activity (CardViewActivity).
            getActivity().finish();
        }
    });

    getDialog().setOnKeyListener(new DialogInterface.OnKeyListener() {
        @Override
        public boolean onKey(android.content.DialogInterface dialog, int keyCode, KeyEvent event) {
            if ((keyCode == android.view.KeyEvent.KEYCODE_BACK)) {
             if (event.getAction()!= KeyEvent.ACTION_DOWN)
                    // Next line dismisses the dialogfragment
                    dismiss();
                    // Next line returns to the previous activity (MainActivity) by closing the fragment and
                    // the current activity (CardViewActivity).
                    getActivity().finish();
                    return true;
                }
            return false;
        }
    });
    return rootView;
}

}

Answer 1

看到问题是你启动了一个Activity并且你有一些变量。旋转屏幕时，您使用变量销毁了该活动。现在，当您到达onDismiss时，您正试图解除已在轮换更改时销毁的值。

您可以尝试制作变量static。所以它变成了'staticvariable＆＃39; .dismissDialog（）。

如何消除DatePickerDialog方向更改时的onDismiss错误？

1 个答案: