android-处理dialogFragment按钮点击

Question

public class CompanyNotConnectedToSRDialog extends DialogFragment {

    public static final String TAG = CompanyNotConnectedToSRDialog.class.getSimpleName();

    private NotConnectedDialogListener mNotConnectedDialogListener;

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        return new AlertDialog.Builder(getActivity(), R.style.DefaultAlertDialogTheme)
                .setTitle("Register")
                .setMessage("Do you really want to register?")
                .setNeutralButton("Skip", (dialog1, which) -> {
                    mNotConnectedDialogListener.onSkipBtnNotConnectedDialogPressed();
                })
                .setNegativeButton("Cancel", null)
                .setPositiveButton("Register", (dialog12, which) -> {
                    mNotConnectedDialogListener.onSendBtnNotConnectedDialogPressed();
                })
                .create();
    }


    public interface NotConnectedDialogListener {
        void onSkipBtnNotConnectedDialogPressed();
        void onSendBtnNotConnectedDialogPressed();
    }

    public void setListener(NotConnectedDialogListener listener) {
        this.mNotConnectedDialogListener = listener;
    }

if (mNotConnectedDialog == null) {
            mNotConnectedDialog = new CompanyNotConnectedToSRDialog();
            mNotConnectedDialog.setListener(this);
            mNotConnectedDialog.show(getActivity().getFragmentManager(), CompanyNotConnectedToSRDialog.TAG);
        } else {
            mNotConnectedDialog.show(mActivity.getFragmentManager(), CompanyNotConnectedToSRDialog.TAG);
            mNotConnectedDialog.setListener(this);
        }

java.lang.NullPointerException: Attempt to invoke interface method 'void com.myapp.ui.object.create.dialogs.CompanyNotConnectedToSRDialog$NotConnectedDialogListener.onSendBtnNotConnectedDialogPressed()' on a null object reference

at com.myapp.ui.object.create.dialogs.CompanyNotConnectedToSRDialog.lambda$onCreateDialog$1(CompanyNotConnectedToSRDialog.java:31)

如果这个解决方案是错误的，如何处理这些点击和设置监听器？

PS：请不要告诉我android:configchanges。

Answer 1

是的，在方向改变后，您的侦听器是空的。对活动进行回调是最简单的：

public static class DialogFragmentA extends DialogFragment {

    // Container Activity must implement this interface
    public interface NotConnectedDialogListener {
        public void onX();
    }

    NotConnectedDialogListener mListener;
    ...
    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        try {
            mListener = (NotConnectedDialogListener) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(activity.toString() + " must implement NotConnectedDialogListener");
        }
    }
    ...
}

现在，您可以在任何位置的对话框中调用mlistener.onx等，也可以在方向改变后调用。您的容器活动必须实现接口，并将接收方法调用。

https://developer.android.com/guide/components/fragments.html#eventcallbacks