public Main(){
        f = new JFrame("Admin Page");
        panelUtama = new JPanel();
        panelIsi = new JPanel();
        panelTombol = new JPanel();
        bLogin = new JButton("Login");
        lSignIn = new JLabel("Sign In !");
        lUsername = new JLabel("Username");
        lPassword = new JLabel("Password");
        tfUsername = new JTextField(10);
        pfPassword = new JPasswordField(10);  
    }