Android DialogFragment throws ClassCastException from getActivity()

Question

I want to obtain the value in DialogFragment: enter a value into an EditText and change the TextView in Fragment regarding it.

My Fragment

public class MyPageActivity extends Fragment implements MyPageNicknameDialog.onNicknameListener{
...

@Override
public void setNicknameListener(String arg){
    mypage_nickname_text.setText(arg);
}
}

Dialog

public class MyPageNicknameDialog extends DialogFragment{

...

public interface onNicknameListener{
    void setNicknameListener(String arg);
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){

    dialogView = inflater.inflate(R.layout.dialog_nickname_mypage, container, false);

    getDialog().getWindow().requestFeature(Window.FEATURE_NO_TITLE);  
    getDialog().getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN); 

    nickname_dialog_edittext = (EditText)dialogView.findViewById(R.id.nickname_dialog_edittext);
    nickname_dialog_edittext.requestFocus();
    nickname_dialog_edittext.setOnEditorActionListener( new OnEditorActionListener() {

        @Override
        public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {

            // Here thorws ClasscastExeption
            onNicknameListener activity = (onNicknameListener) getActivity();
            activity.setNicknameListener(nickname_dialog_edittext.getText().toString());
            getDialog().dismiss();

            return false;
        }
    });

    //init();

    return dialogView;
}
}

The Log

05-21 22:48:42.725: E/AndroidRuntime(17131): java.lang.ClassCastException: com.hhh.kiznic.MainFragmentActivity cannot be cast to com.hhh.kiznic.MyPageNicknameDialog$onNicknameListener
05-21 22:48:42.725: E/AndroidRuntime(17131):    at com.hhh.kiznic.MyPageNicknameDialog$1.onEditorAction(MyPageNicknameDialog.java:54)
05-21 22:48:42.725: E/AndroidRuntime(17131):    at android.widget.TextView.onEditorAction(TextView.java:4973)
05-21 22:48:42.725: E/AndroidRuntime(17131):    at com.android.internal.widget.EditableInputConnection.performEditorAction(EditableInputConnection.java:138)
05-21 22:48:42.725: E/AndroidRuntime(17131):    at com.android.internal.view.IInputConnectionWrapper.executeMessage(IInputConnectionWrapper.java:297)
05-21 22:48:42.725: E/AndroidRuntime(17131):    at com.android.internal.view.IInputConnectionWrapper$MyHandler.handleMessage(IInputConnectionWrapper.java:77)
05-21 22:48:42.725: E/AndroidRuntime(17131):    at android.os.Handler.dispatchMessage(Handler.java:99)
05-21 22:48:42.725: E/AndroidRuntime(17131):    at android.os.Looper.loop(Looper.java:137)
05-21 22:48:42.725: E/AndroidRuntime(17131):    at android.app.ActivityThread.main(ActivityThread.java:5493)
05-21 22:48:42.725: E/AndroidRuntime(17131):    at java.lang.reflect.Method.invokeNative(Native Method)
05-21 22:48:42.725: E/AndroidRuntime(17131):    at java.lang.reflect.Method.invoke(Method.java:525)
05-21 22:48:42.725: E/AndroidRuntime(17131):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1209)
05-21 22:48:42.725: E/AndroidRuntime(17131):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1025)
05-21 22:48:42.725: E/AndroidRuntime(17131):    at dalvik.system.NativeStart.main(Native Method)

I was find many examples but could not be resolved. If you know the cause and solution please help me.

Answer 1

When you're opening a DialogFragment inside another Fragment

dialog.show(getChildFragmentManager(), "dialog");

you can get the parent fragment by getParentFragment()

So your code needs to be like this:

    @Override
    public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {

        // Here thorws ClasscastExeption
        onNicknameListener parentFrag = (onNicknameListener) getParentFragment();
        parentFrag.setNicknameListener(nickname_dialog_edittext.getText().toString());
        getDialog().dismiss();

        return false;
    }