BaseActivity, BaseFragment

• abstract class는 인스턴스화 될 수 없으며 반드시 상속되어야 함.
• 반드시 구현해야 할 function을 정의할 수 있음

abstract class DefaultActivity<T: ViewDataBinding>(@LayoutRes val resId: Int): AppCompatActivity() {
    val binding: T by lazy { DataBindingUtil.setContentView(this, resId) }
    val viewModel by viewModel<MainViewModel>()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(binding.root)
    }
}

abstract class DefaultFragment<T: ViewDataBinding>(@LayoutRes val resId: Int): Fragment() {
    lateinit var binding: T
    val viewModel by viewModel<MainViewModel>()

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        binding = DataBindingUtil.inflate(inflater, resId, container, false)
        return binding.root
    }
    fun applicationContext(): Context = requireActivity().applicationContext
}