Do not see the EditNameDialogListener interface

Question

I want to pass back the user line in the dialog fragment: "AddFriendDialogFragment.java" back to the activity named by it: "HomeActivity.java". I do this through the interface declared inside "AddFriendDialogFragment.java": "EditNameDialogListener". However, for some reason, HomeActivity does not see this interface, so I get the message "Can not solve symbol:" EditNameDialogListener ".

"HomeActivity.java":

package tutorial.com.example.jerryhou.dialogactionbartutorial; import android.app.Activity; import android.app.DialogFragment; import android.app.FragmentManager; import android.os.Bundle; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.widget.Toast; public class HomeActivity extends Activity implements EditNameDialogListener { @Override public void onFinishEditDialog(String inputText) { Toast.makeText(this, "Hi, " + inputText, Toast.LENGTH_SHORT).show(); } public void showUsernameSearchDialog(View v) { FragmentManager fragmentManager = getFragmentManager(); DialogFragment newFragment = new AddFriendDialogFragment(); newFragment.show(fragmentManager, "AddFriendDialog"); } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_home); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.menu_home, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { // Handle action bar item clicks here. The action bar will // automatically handle clicks on the Home/Up button, so long // as you specify a parent activity in AndroidManifest.xml. int id = item.getItemId(); //noinspection SimplifiableIfStatement if (id == R.id.action_settings) { return true; } return super.onOptionsItemSelected(item); } } 

"AddFriendDialogFragment.java":

 package tutorial.com.example.jerryhou.dialogactionbartutorial; import android.app.Activity; import android.app.AlertDialog; import android.app.Dialog; import android.app.DialogFragment; import android.content.DialogInterface; import android.net.Uri; import android.os.Bundle; import android.app.Fragment; import android.util.Log; import android.view.KeyEvent; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.view.inputmethod.EditorInfo; import android.widget.EditText; import android.widget.TextView; public class AddFriendDialogFragment extends DialogFragment { private static final String TAG = "AddFriendDialogFragment"; public interface EditNameDialogListener { void onFinishEditDialog(String inputText); } @Override public Dialog onCreateDialog(Bundle savedInstanceState) { AlertDialog.Builder builder = new AlertDialog.Builder(getActivity()); // Get the layout inflater LayoutInflater inflater = getActivity().getLayoutInflater(); // Inflate and set the layout for the dialog // Pass null as the parent view because its going in the dialog layout View addFriendDialogView = inflater.inflate(R.layout.fragment_add_friend_dialog, null); // Set an EditText view to get user input final EditText usernameEditText = (EditText) addFriendDialogView.findViewById(R.id.username); builder.setView(addFriendDialogView) // Add action buttons .setPositiveButton(R.string.search, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int id) { //Retrieve Username typed in String username_querystr = usernameEditText.getText().toString(); //Correctly retrieving query str Log.v(TAG, "Going to search " + username_querystr); //Pass back query str to search in HomeActivity EditNameDialogListener activity = (EditNameDialogListener) getActivity(); activity.onFinishEditDialog(usernameEditText.getText().toString()); } }) .setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { AddFriendDialogFragment.this.getDialog().cancel(); } }); return builder.create(); } } 

Answer 1

Even if they are in the same package, you cannot directly use EditNameDialogListener , since it is an internal interface .

You have 2 options:

-> Use the full name EditNameDialogListener , i.e. AddFriendDialogFragment.EditNameDialogListener

 public class HomeActivity extends Activity implements AddFriendDialogFragment.EditNameDialogListener 

-> Import explicitly EditNameDialogListener

 import tutorial.com.example.jerryhou.dialogactionbartutorial.AddFriendDialogFragment.EditNameDialogListener public class HomeActivity extends Activity implements EditNameDialogListener 

Answer 2

The name of the implemented interface must be AddFriendDialogFragment.EditNameDialogListener

 public class HomeActivity extends Activity implements AddFriendDialogFragment.EditNameDialogListener 

Answer 3

You can either copy the interface to a separate module / compilation file

OR

possibly using the static scope identifier in front of your interface

 public static interface EditNameDialogListener {...} 

and something like @Hacketo mentioned will help:

 public class HomeActivity extends Activity implements AddFriendDialogFragment.EditNameDialogListener