我有一个基本的 ViewController 和一个基本的 ViewModel。基础 ViewModel 由基础 ViewController 使用。此外,我有 2 个 ViewController 子类和 2 个 ViewModel 子类需要一起使用。
例子:
class BaseViewModel {
func somethingBasic() {}
}
class ConcreteViewModel1: BaseViewModel {
func somethingConcrete1() {}
}
class ConcreteViewModel2: BaseViewModel {
func somethingConcrete2() {}
}
class BaseViewController {
let viewModel: BaseViewModel
init(with viewModel: BaseViewModel) {
self.viewModel = viewModel
}
}
class ConcreteViewController1: BaseViewController {
init(with viewModel: ConcreteViewModel1) {
super.init(with: viewModel)
}
func useViewModel() {
viewModel.somethingBasic()
viewModel.somethingConcrete1() //this does not work
}
}
class ConcreteViewController2: BaseViewController {
init(with viewModel: ConcreteViewModel2) {
super.init(with: viewModel)
}
func useViewModel() {
viewModel.somethingBasic()
viewModel.somethingConcrete2() //this does not work
}
}
问题是:使 viewmodel.somethingConcrete1()
和 viewmodel.somethingConcrete2()
工作的首选解决方案是什么?
最佳答案
为此尝试使用Generics
。
在 BaseViewController
中创建 init
接受一个 generic parameter T
constrained to type BaseViewModel
,即
class BaseViewController<T: BaseViewModel> {
let viewModel: T
init(with viewModel: T) {
self.viewModel = viewModel
}
}
现在从 BaseViewController
继承 ConcreteViewController1
和 ConcreteViewController2
为通用参数 T
,即
class ConcreteViewController1: BaseViewController<ConcreteViewModel1> {
func useViewModel() {
viewModel.somethingBasic()
viewModel.somethingConcrete1()
}
}
class ConcreteViewController2: BaseViewController<ConcreteViewModel2> {
func useViewModel() {
viewModel.somethingBasic()
viewModel.somethingConcrete2()
}
}
关于ios - 如何确保相同的继承层次结构,例如对于 MVVM,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/57322027/