Preface: POP and OOP are not mutually exclusive. They’re design paradigms that are greatly related. The primary aspect of POP over OOP is that is prefers composition over inheritance. There are several benefits to this. In large inheritance hierarchies, the ancestor classes tend to contain most of the (generalized) functionality, with the leaf subclasses making … Read more
This was answered by an official Swift developer (Slava_Pestov) on the Swift forums. Here is the summary: You should use AnyObject (protocol SomeProtocol: AnyObject). AnyObject and class are equivalent. There is no difference. class will eventually be deprecated.
Protocols with type aliases cannot be used this way. Swift doesn’t have a way to talk directly about meta-types like ValidationRule or Array. You can only deal with instantiations like ValidationRule where… or Array<String>. With typealiases, there’s no way to get there directly. So we have to get there indirectly with type erasure. Swift has … Read more
You could use the UITextField input view property. Just alloc init a regular UIDatePicker in code and assign it to the textfield’s inputView. Doing this, the UIPickerView will be presented instead of the keyboard. If you need any code feel free to ask 🙂 EDIT: code You fist hook up your textField with IB @interface … Read more
Use a generic type constrained to Encodable func saveObject<T : Encodable>(_ object: T, at location: String) { //Some code let data = try JSONEncoder().encode(object) //Some more code }
To sum up everything I read here and the solution which worked for me: struct ContainerView<Content: View>: View { @ViewBuilder var content: Content var body: some View { content } } This not only allows you to put simple Views inside, but also, thanks to @ViewBuilder, use if-else and switch-case blocks: struct SimpleView: View { … Read more
You may be running into https://bugs.swift.org/browse/SR-10257 in the Swift 5.0 compiler. This would happen if you have at least three files: BasicViewController.swift SomeOtherFile.swift ExampleViewController.swift If SomeOtherFile.swift makes any calls to an AnyObject-typed value, you’re compiling in wholemodule mode, and the files are passed to the compiler in the above order (with SomeOtherFile.swift in the middle … Read more
It seems there are two use-cases of why you may want to do what you are doing. In the first use-case, Swift will allow you to do what you want, but not very cleanly in the second use-case. I’m guessing you fall into the second category, but I’ll go through both. Extending the functionality of … Read more
Use a delegate if you want to talk to only one object. For example, a tableView has a delegate – only one object should be responsible for dealing with it. Use notifications if you want to tell everyone that something has happened. For example in low memory situations a notification is sent telling your app … Read more
Wrappers and stored properties are not allowed in swift protocols and extensions, at least for now. So I would go with the following approach mixing protocols, generics and classes… (all compilable and tested with Xcode 11.2 / iOS 13.2) // base model protocol protocol ItemViewModel: ObservableObject { var title: String { get set } func … Read more