title: error: cannot find symbol class FirebaseInstanceIdService
body: <pre><code>    public class LoginActivity extends AppCompatActivity {
  
      private static final int RC_SIGN_IN = 1;
  
      @BindView(R.id.activity_login_google_button)
      SignInButton googleButton;
      @BindView(R.id.activity_login_progress)
      ProgressBar progress;
  
      private GoogleApiClient mGoogleApiClient;
      private FirebaseAuth.AuthStateListener mAuthListener;
      private FirebaseAuth mAuth;
  
      @State
      boolean isLoading;
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_login);
          ButterKnife.bind(this);
          Icepick.restoreInstanceState(this, savedInstanceState);
  
          GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
                  .requestEmail()
                  .requestIdToken(getString(R.string.default_web_client_id))
                  .build();
  
          mGoogleApiClient = new GoogleApiClient.Builder(this)
                  .addApi(Auth.GOOGLE_SIGN_IN_API, gso)
                  .build();
  
          mAuth = FirebaseAuth.getInstance();
  
          mAuthListener = new FirebaseAuth.AuthStateListener() {
              @Override
              public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
                  FirebaseUser user = firebaseAuth.getCurrentUser();
                  if (user != null) {
                      // User is signed in
                      Log.d("@@@@", "onAuthStateChanged:signed_in:" + user.getUid());
                      Intent home = new Intent(LoginActivity.this, MainActivity.class);
                      startActivity(home);
                      finish();
                  } else {
                      // User is signed out
                      Log.d("@@@@", "onAuthStateChanged:signed_out");
                  }
              }
          };
  
          displayLoadingState();
      }
  
      @Override
      protected void onSaveInstanceState(Bundle outState) {
          super.onSaveInstanceState(outState);
          Icepick.saveInstanceState(this, outState);
      }
  
      @Override
      public void onStop() {
          super.onStop();
          if (mAuthListener != null) {
              mAuth.removeAuthStateListener(mAuthListener);
          }
      }
  
      @Override
      public void onStart() {
          super.onStart();
          if (mAuthListener != null) {
              mAuth.addAuthStateListener(mAuthListener);
          }
      }
  
      @Override
      public void onActivityResult(int requestCode, int resultCode, Intent data) {
          super.onActivityResult(requestCode, resultCode, data);
  
          // Result returned from launching the Intent from GoogleSignInApi.getSignInIntent(...);
          if (requestCode == RC_SIGN_IN) {
              hideProgress();
              GoogleSignInResult result = Auth.GoogleSignInApi.getSignInResultFromIntent(data);
              handleGoogleSignInResult(result);
          }
      }
  
      private void hideProgress() {
          isLoading = false;
          displayLoadingState();
      }
  
      private void displayLoadingState() {
          progress.setVisibility(isLoading ? VISIBLE : GONE);
          googleButton.setVisibility(!isLoading ? VISIBLE : GONE);
      }
  
      private void showProgress() {
          isLoading = true;
          displayLoadingState();
      }
  
      private void handleGoogleSignInResult(GoogleSignInResult result) {
          if (result.isSuccess()) {
              // Google Sign In was successful, authenticate with Firebase
              GoogleSignInAccount account = result.getSignInAccount();
              firebaseAuthWithGoogle(account);
          } else {
              Toast.makeText(this, R.string.error_google_sign_in, Toast.LENGTH_SHORT).show();
          }
      }
  
      private void firebaseAuthWithGoogle(GoogleSignInAccount acct) {
          Log.d("@@@@", "firebaseAuthWithGoogle:" + acct.getId());
  
          AuthCredential credential = GoogleAuthProvider.getCredential(acct.getIdToken(), null);
          mAuth.signInWithCredential(credential)
                  .addOnCompleteListener(this, new OnCompleteListener&lt;AuthResult&gt;() {
                      @Override
                      public void onComplete(@NonNull Task&lt;AuthResult&gt; task) {
                          Log.d("@@@@", "firebaseAuthWithGoogleComplete:" + task.isSuccessful());
  
                          Needle.onBackgroundThread().execute(new Runnable() {
                              @Override
                              public void run() {
                                  try {
                                      FirebaseInstanceId.getInstance().deleteInstanceId();
                                  } catch (IOException e) {
                                      Log.d("@@@@", "deleteInstanceIdCatch: " + e.getMessage());
                                  }
                              }
                          });
  
                          if (!task.isSuccessful()) {
                              Log.w("@@@@", "firebaseAuthWithGoogleFailed", task.getException());
                              Toast.makeText(LoginActivity.this, R.string.error_google_sign_in, Toast.LENGTH_SHORT).show();
                          }
                      }
                  });
      }
  
      @OnClick(R.id.activity_login_google_button)
      public void attemptGoogleSignIn() {
          Intent signInIntent = Auth.GoogleSignInApi.getSignInIntent(mGoogleApiClient);
          startActivityForResult(signInIntent, RC_SIGN_IN);
          showProgress();
      }
  }    
  </code></pre>
  
  <p>this is the login activity code 
  in which I'm getting an error  that
  cannot find symbol class FirebaseInstanceIdService
  I have attached an image for reference  </p>
  
  <p><img src="https://i.stack.imgur.com/zdOgB.jpg" alt=""></p>
  
  <p>this is for my final year project which is a chatting based application 
  because of this process, I cannot able to generate APK but Gradle sync is successful.</p>