title: Getting 'Cannot resolve method 'addOnCompletionListener()'.......' while trying to place some code inside builder.setPositiveButton's onClick() method
body: <p>I'm trying to place some code inside <code>AlertDialog.Builder</code>'s <code>builder.setPositiveButton</code> method. </p>
  
  <p>The problem is that I'm getting the following error: <code>Cannot resolve method 'addOnCompletionListener(anonymous android.content.DialogInterface.OnClickListener, anonymous com.google.android.gms.tasks.OnCompletionListener&lt;com.google.firebase.auth.AuthResult&gt;)</code></p>
  
  <p>Here's the code:</p>
  
  <pre><code>    AlertDialog.Builder builder = new AlertDialog.Builder(SignUpActivity.this);
                  builder.setTitle("Title");
                  builder.setView(R.layout.customlayout);
                  builder.setPositiveButton("Continue", new DialogInterface.OnClickListener() {
                      @Override
                      public void onClick(DialogInterface dialogInterface, int i) {
  
  //error from below line
  
                     mAuth.createUserWithEmailAndPassword(userEmail.getText().toString(), userPassword.getText().toString())
                                  .addOnCompleteListener(this, new OnCompleteListener&lt;AuthResult&gt;() {
                                      @Override
                                      public void onComplete(@NonNull Task&lt;AuthResult&gt; task) {
                                          Log.d("signUpSuccessful", "createUserWithEmail:onComplete:" + task.isSuccessful());
  
                                          // If sign in fails, display a message to the user. If sign in succeeds
                                          // the auth state listener will be notified and logic to handle the
                                          // signed in user can be handled in the listener.
                                          if (!task.isSuccessful()) {
                                              Snackbar snackbar = Snackbar
                                                      .make(coordinatorLayout, "Sign up failed. Please retry.", Snackbar.LENGTH_SHORT);
                                              snackbar.show();
                                          }
  
                                          // ...
                                      }
                                  });
  
  //upto this line
                      }
                  });
                  AlertDialog dialog = builder.create();
                  dialog.show();
  </code></pre>
  
  <p>What's wrong here?</p>
  
  <p>Please let me know.</p>