Error: This fragment should provide a default constructor (a public constructor with no arguments)

Question

My class extends DialogFragment like this:

public class DatePickerFragment extends DialogFragment implements DatePickerDialog.OnDateSetListener {

    EditText editDate;
    private Calendar dateTime = Calendar.getInstance();
    private SimpleDateFormat dateFormatter = new SimpleDateFormat("dd MMMM yyyy");

    public DatePickerFragment(EditText editText) {
        editDate = editText;
    }

@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
    // Use the current date as the default date in the picker
    final Calendar c = Calendar.getInstance();
    int year = c.get(Calendar.YEAR);
    int month = c.get(Calendar.MONTH);
    int day = c.get(Calendar.DAY_OF_MONTH);

    // Create a new instance of DatePickerDialog and return it
    return new DatePickerDialog(getActivity(), this, year, month, day);

}

@Override
public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
        dateTime.set(year, monthOfYear, dayOfMonth);
        editDate.setText(dateFormatter
                .format(dateTime.getTime()));
    }

}

And this is how i am using it in Activity:

public void showDatePickerDialog(View v) {
        new DatePickerFragment((EditText) v).show(getSupportFragmentManager(), "datePicker");
    }

And calling like this:

    <EditText
        android:id="@+id/editDate"
        android:onClick="showDatePickerDialog" />

But I am always getting :

Error: This fragment should provide a default constructor (a public constructor with no arguments)

Answer 1

The newer version of Android SDK forces you to get a empty, no-args constructor. It's now a good practice to do this. This allows you to save the instance state into bundle and Android will recreate your fragment calling the default constructor.

In this case, you have the following solutions:

First, create the default constructor:

public DatePickerFragment() {}

Create the instance and set the EditText via setter method:

DatePickerFragment fragment = new DatePickerFragment();
fragment.setEditText(v); // create this setter
fragment.show();

Since EditText is parcelable, you can also set as arguments:

DatePickerFragment fragment = new DatePickerFragment();
Bundle bundle = new Bundle();
bundle.putExtra("EditText", v); 
fragment.setArguments(bundle); // setArguments is a method that already exists in fragments.
fragment.show(getSupportFragmentManager(), "DatePicker");

[EDIT] As suggested, try to ignore these errors configuring build.gradle like this:

lintOptions { 
  abortOnError false 
  checkReleaseBuilds false 
} 

This will not stop the build of your application by using non-default constructor in fragments.

Answer 2

You need to remove this constructor

public DatePickerFragment(EditText editText) {
    editDate = editText;
}

You should not pass a View reference to Fragment. If you want to update an EditText in Activity or elsewhere then use listener.

Answer 3

      public DatePickerFragment() {}

        @Override
        public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
                dateTime.set(year, monthOfYear, dayOfMonth);
             //   editDate.setText(dateFormatter
             //         .format(dateTime.getTime()));
            Intent intent = new Intent();
            intent.setAction("CUSTOM_INTENT_FOR_SETTING_EDITTEXT");
            Bundle bundle = new Bundle();
            bundle.putString("my_data", dateTime.getTime.toString());
            intent.putExtras(bundle);
            sendBroadcast(intent);
            }




public class SubmitFragment extends Fragment {

    View view;
    EditText editDate;
    String strDate;
    Button btnSubmit;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        view = inflater.inflate(R.layout.fragment_submit, container, false);

        editDate = (EditText) view.findViewById(R.id.editDate);

        btnSend = (Button) view.findViewById(R.id.buttonSend);
        btnSend.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                strDate = editDate.getText().toString();
                Log.v("strDate..... >>>", strDate);

            }
        });

        return view;
    }


        // Our handler for received Intents. This will be called whenever an Intent
        // with an action named "CUSTOM_INTENT_FOR_SETTING_EDITTEXT" is broadcasted.
        private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
          @Override
          public void onReceive(Context context, Intent intent) {
            // Get extra data included in the Intent
            String message = intent.getStringExtra("my_data");
            Log.d("receiver", "message: " + message);
        *****// Use this message to set Edittext here...*****
          }
        };


        @Override
        protected void onPause() {
          // Unregister since the activity is about to be closed.
          LocalBroadcastManager.getInstance(getactivity()).unregisterReceiver(mMessageReceiver);
          super.onDestroy();
        }


        @Override
        protected void onResume() {
          // register the receiver here..
       super.onResume(); LocalBroadcastManager.getInstance(getactivity()).registerReceiver(mMessageReceiver,
              new IntentFilter("CUSTOM_INTENT_FOR_SETTING_EDITTEXT"));
        }
}

Hope this helps..what exactly i am doing here is using localBroadcast to do the needful..another way would have been using a interface to the settext but one wrong thing about that approach is that when app is in background for so long , it will return null when oncreateview is called again.

Answer 4

Add @SuppressLint("ValidFragment")

before your class,

public class DatePickerFragment extends

I hope it helps you