Firebase Authentication Not working in signed APK
<p>I'm using Firebase Google Sign in. It works perfectly via USB debugging. But when I generate signed APK, it stops working. Its not able to sign in. Using it on Android 5.1 &amp; Android 6.0.1. Also, if the Google play services is not updated, it gives user prompt to update it because of which user may leave the app. How can I turn off the prompt and solve the error?</p>

<pre><code>public class MainActivity extends AppCompatActivity implements  GoogleApiClient.OnConnectionFailedListener,
        View.OnClickListener {
private Button skip;
    private static final String TAG = "GoogleActivity";
    private static final int RC_SIGN_IN = 9001;
    private ProgressBar pb;
    // [START declare_auth]
    private FirebaseAuth mAuth;
    // [END declare_auth]

    // [START declare_auth_listener]
    private FirebaseAuth.AuthStateListener mAuthListener;
    // [END declare_auth_listener]

    private GoogleApiClient mGoogleApiClient;
    private TextView mStatusTextView;
    private TextView mDetailTextView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        pb=(ProgressBar)findViewById(R.id.signpro);
        pb.setVisibility(View.GONE);
        skip=(Button)findViewById(R.id.btnskip);
        skip.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                setContentView(R.layout.activity_home);
            }
        });
        // Views


        // Button listeners
        findViewById(R.id.sign_in_button).setOnClickListener(this);

        // [START config_signin]
        // Configure Google Sign In
        GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
                .requestIdToken(getString(R.string.default_web_client_id))
                .requestEmail()
                .build();
        // [END config_signin]

        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .enableAutoManage(this /* FragmentActivity */, this /* OnConnectionFailedListener */)
                .addApi(Auth.GOOGLE_SIGN_IN_API, gso)
                .build();

        // [START initialize_auth]
        mAuth = FirebaseAuth.getInstance();
        // [END initialize_auth]

        // [START auth_state_listener]
        mAuthListener = new FirebaseAuth.AuthStateListener() {
            @Override
            public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {

                FirebaseUser user = firebaseAuth.getCurrentUser();
                if (user != null) {
                    // User is signed in
                    Log.d(TAG, "onAuthStateChanged:signed_in:" + user.getUid());
                    setContentView(R.layout.activity_home);

                } else {
                    // User is signed out
                    Log.d(TAG, "onAuthStateChanged:signed_out");
                }
                // [START_EXCLUDE]

                // [END_EXCLUDE]
            }
        };
        // [END auth_state_listener]
    }

    // [START on_start_add_listener]
    @Override
    public void onStart() {
        super.onStart();
        mAuth.addAuthStateListener(mAuthListener);

    }
    // [END on_start_add_listener]

    // [START on_stop_remove_listener]
    @Override
    public void onStop() {
        super.onStop();
        if (mAuthListener != null) {
            mAuth.removeAuthStateListener(mAuthListener);
        }
    }
    // [END on_stop_remove_listener]

    // [START onactivityresult]
    @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) {
            GoogleSignInResult result = Auth.GoogleSignInApi.getSignInResultFromIntent(data);
            if (result.isSuccess()) {
                Toast.makeText(this, "Signing you in. Please Wait...", Toast.LENGTH_LONG).show();
                // Google Sign In was successful, authenticate with Firebase
                GoogleSignInAccount account = result.getSignInAccount();
                firebaseAuthWithGoogle(account);
                Toast.makeText(this, "Sign In Successful!", Toast.LENGTH_SHORT).show();
            } else {
                // Google Sign In failed, update UI appropriately
                // [START_EXCLUDE]

                Toast.makeText(this, "Google Sign In failed. Please Skip.", Toast.LENGTH_SHORT).show();
                pb.setVisibility(View.GONE);
                // [END_EXCLUDE]
            }
        }
    }
    // [END onactivityresult]

    // [START auth_with_google]
    private void firebaseAuthWithGoogle(GoogleSignInAccount acct) {
        Log.d(TAG, "firebaseAuthWithGoogle:" + acct.getId());
        // [START_EXCLUDE silent]

        // [END_EXCLUDE]

        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(TAG, "signInWithCredential: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()) {
                            Log.w(TAG, "signInWithCredential", task.getException());
                            Toast.makeText(MainActivity.this, "Authentication failed.",
                                    Toast.LENGTH_SHORT).show();
                        }
                        // [START_EXCLUDE]

                        // [END_EXCLUDE]
                    }
                });
    }
    // [END auth_with_google]

    // [START signin]
    private void signIn() {
        pb.setVisibility(View.VISIBLE);
        Intent signInIntent = Auth.GoogleSignInApi.getSignInIntent(mGoogleApiClient);
        startActivityForResult(signInIntent, RC_SIGN_IN);
    }
    // [END signin]



    @Override
    public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
        // An unresolvable error has occurred and Google APIs (including Sign-In) will not
        // be available.
        Log.d(TAG, "onConnectionFailed:" + connectionResult);
        Toast.makeText(this, "Google Play Services error.", Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onClick(View v) {
        int i = v.getId();
        if (i == R.id.sign_in_button) {
            signIn();

        }
    }
}
</code></pre>