public class LoginActivity extends AppCompatActivity {

    private Context context;
    private boolean status = false;
    FragmentTransaction fT;
    FragmentManager fM;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);

        context = this;

        Glide.with(this).load(R.drawable.login_header_image)
                .bitmapTransform(new BlurTransformation(context, 20))
                .into((ImageView) findViewById(R.id.login_background));

        fM = getSupportFragmentManager();
        fT = fM.beginTransaction();

        if (!status) {
            LoginFragment f1 = new LoginFragment();
            fT.add(R.id.login_cardView, f1);
            fT.commit();
            status = true;
        }

        FloatingActionButton f = (FloatingActionButton) findViewById(R.id.login_registerButton);
        f.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                if (!status) {
                    LoginFragment f1 = new LoginFragment();
                    fM.beginTransaction().add(R.id.login_cardView, f1)
                            .commit();
                    status = true;
                }else {
                    RegisterFragment f2 = new RegisterFragment();
                    fM.beginTransaction().add(R.id.login_cardView, f2)
                            .commit();
                    status = false;
                }
            }
        });
    }