[SOLVED] googlesigninbutton doesn't react to click

My Google sign in button doesn't work and I don't know why. I made an OnClickListener which should work but the Google Signin Button never responds.

Here, my code:

public class TabbedActivity extends AppCompatActivity {
    private SectionsPagerAdapter mSectionsPagerAdapter;
    private static final String TAG = "LoginProcess";
    Intent mapIntent;
    SignInButton gsignInButton;
    private static final int RC_SIGN_IN = 1;
    LayoutInflater inflater;
    View rootView;
    FirebaseAuth mAuth;
    FirebaseAuth.AuthStateListener mAuthListener;

    /**
     * The {@link ViewPager} that will host the section contents.
     */
    private ViewPager mViewPager;
    GoogleSignInOptions gso;
    GoogleApiClient mGoogleApiClient;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_tabbed);
        mapIntent = new Intent(TabbedActivity.this, MapsActivity.class);
        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
                    Toast.makeText(TabbedActivity.this, "onAuthStateChanged:signed_in:" + user.getUid(), Toast.LENGTH_SHORT).show();
                    startActivity(mapIntent);
                    finish();
                } else {
                    // User is signed out
                    Toast.makeText(TabbedActivity.this, "onAuthStateChanged:signed_out", Toast.LENGTH_SHORT).show();

                }

            }
        };

        inflater = getLayoutInflater();
        rootView = inflater.inflate(R.layout.welcomescreenlogin,  null);
        gsignInButton = (SignInButton) rootView.findViewById(R.id.sign_in_button);
        gsignInButton.setOnClickListener(onClick);


        gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
                .requestIdToken(getString(R.string.default_web_client_id))
                .requestEmail()
                .build();

        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addApi(Auth.GOOGLE_SIGN_IN_API, gso)
                .build();

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        // Create the adapter that will return a fragment for each of the three
        // primary sections of the activity.
        mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());

        // Set up the ViewPager with the sections adapter.
        mViewPager = (ViewPager) findViewById(R.id.container);
        mViewPager.setAdapter(mSectionsPagerAdapter);


    }

    View.OnClickListener onClick = new View.OnClickListener() {
        public void onClick(View v) {
    signIn();
        }
    };

    @Override
    protected void onStart() {
        super.onStart();
        mAuth.addAuthStateListener(mAuthListener);

    }

    @Override
    protected void onStop() {
        super.onStop();
        if (mAuthListener != null) {
            mAuth.removeAuthStateListener(mAuthListener);
        }

    }

    public void signIn() {
        Intent signInIntent = Auth.GoogleSignInApi.getSignInIntent(mGoogleApiClient);
        startActivityForResult(signInIntent, RC_SIGN_IN);
    }

    @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()) {
                // Google Sign In was successful, authenticate with Firebase
                GoogleSignInAccount account = result.getSignInAccount();
                firebaseAuthWithGoogle(account);
            } else {
                Toast.makeText(TabbedActivity.this, "Signup Error", Toast.LENGTH_LONG).show();
                // Google Sign In failed, update UI appropriately
                // ...
            }
        }
    }

    private void firebaseAuthWithGoogle(GoogleSignInAccount acct) {
        Log.d(TAG, "firebaseAuthWithGoogle:" + acct.getId());

        AuthCredential credential = GoogleAuthProvider.getCredential(acct.getIdToken(), null);
        mAuth.signInWithCredential(credential)
                .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                    @Override
                    public void onComplete(@NonNull Task<AuthResult> 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(TabbedActivity.this, "Authentication failed.",
                                    Toast.LENGTH_SHORT).show();
                        }
                        // ...
                    }
                });
            }
        }

And here my Layout

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/welcomegradientlogin">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:text="Sign in to Google"
    android:id="@+id/Welcome"
    android:layout_gravity="center_horizontal|center_vertical"
    android:textColor="#FFFF"
    android:textSize="35sp"
    android:layout_centerVertical="true"
    android:layout_centerHorizontal="true" />

<com.google.android.gms.common.SignInButton
    android:id="@+id/sign_in_button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/Welcome"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="24dp"
    />



</RelativeLayout>

The problem may have to do something with the fact that the class extends "Appcompatactivity" or just that the other methods to execute the signin process aren't written correctly.