title: How to make a user sign out in Firebase?
body: <p>I am making a simple authentication app in Android using Firebase authentication. Till now I am successful in signing the user in, however the issue is that the user remains signed in, and I can't find a way to sign him out.</p>
  
  <p>Here is my MainActivity.java code</p>
  
  <pre><code>public class MainActivity extends AppCompatActivity {
  
      private FirebaseAuth mAuth;
      private FirebaseAuth.AuthStateListener mAuthListener;
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
  
          //tracking the sign in and singn out operations
          mAuth = FirebaseAuth.getInstance();
          mAuthListener = new FirebaseAuth.AuthStateListener(){
              @Override
              public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
                  FirebaseUser user = firebaseAuth.getCurrentUser();
                  if (user!=null){
                      System.out.println("User logged in");
                  }
                  else{
                      System.out.println("User not logged in");
                  }
              }
          };
      }
  
  
      public void onStart(){
          super.onStart();
          mAuth.addAuthStateListener(mAuthListener);
      }
      public void onStop(){
          super.onStop();
          if (mAuthListener != null) {
              mAuth.removeAuthStateListener(mAuthListener);
  
          }
      }
  
  
      public void buttonClicked(View view){
  
          EditText editemail = (EditText) findViewById(R.id.email);
          EditText editpass = (EditText) findViewById(R.id.password);
  
          String email = editemail.getText().toString();
          String password = editpass.getText().toString();
  
  
          mAuth.signInWithEmailAndPassword(email, password)
                  .addOnCompleteListener(this, new OnCompleteListener&lt;AuthResult&gt;() {
                      @Override
                      public void onComplete(@NonNull Task&lt;AuthResult&gt; task) {
                       //   Log.d(TAG, "signInWithEmail:onComplete:" + task.isSuccessful());
                          Toast.makeText(MainActivity.this, "Authentication Success.",
                                  Toast.LENGTH_SHORT).show();
                          startActivity(new Intent(MainActivity.this,Success.class));
                          // 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()) {
                             // Log.w(TAG, "signInWithEmail", task.getException());
                              Toast.makeText(MainActivity.this, "Authentication failed.",
                                      Toast.LENGTH_SHORT).show();
                          }
  
                          // ...
                      }
                  });
      }
  
  
  
  }
  </code></pre>