property-wrapper

问题 Followed this it was working fine. But when I tried the same thing for resolving a nested dependency (Dependency injected class has a dependency in turn - NetworkService In our case), it crashed. What am I doing wrong here? any help would be highly appreciated. A realtime scenario class AppContainer { static let shared = AppContainer() var index: [Any] = [NetworkingLibrary(), NetworkService()] func resolve<T>(_ type: T.Type) -> T { return index.first(where: { $0 as? T != nil }) as! T } }

问题 Followed this it was working fine. But when I tried the same thing for resolving a nested dependency (Dependency injected class has a dependency in turn - NetworkService In our case), it crashed. What am I doing wrong here? any help would be highly appreciated. A realtime scenario class AppContainer { static let shared = AppContainer() var index: [Any] = [NetworkingLibrary(), NetworkService()] func resolve<T>(_ type: T.Type) -> T { return index.first(where: { $0 as? T != nil }) as! T } }

问题 I have been reading about the property wrappers in SwiftUI and I see that they do a great job, but one thing which I really don't get is the difference between @EnvironmentObject and @ObservedObject . From what I learned so far, I see that @EnvironmentObject is used when we have an object that is needed in various places in our app but we don't need to pass it through all of them. For example if we have hierarchy A -> B -> C -> D and the object is created at A, it is saved in the environment

问题 I have been reading about the property wrappers in SwiftUI and I see that they do a great job, but one thing which I really don't get is the difference between @EnvironmentObject and @ObservedObject . From what I learned so far, I see that @EnvironmentObject is used when we have an object that is needed in various places in our app but we don't need to pass it through all of them. For example if we have hierarchy A -> B -> C -> D and the object is created at A, it is saved in the environment

问题 I'm figuring out Property Wrappers in Swift, but I seem to miss something. This is how I wrote a property wrapper for a dependency injection framework we use: @propertyWrapper struct Inject<Value> { var _value: Value var wrappedValue: Value { get { return _value } set { _value = newValue } } init(_ container: Container = AppContainer.shared) { do { _value = try container.resolve(Value.self) } catch let e { fatalError(e.localizedDescription) } } } But when I use it in my class like below, I

问题 How can I use Binding(get: { }, set: { }) custom binding with @Binding property on SwiftUI view. I have used this custom binding successfully with @State variable but doesn't know how to apply it to @Binding in subview initializer. I need it to observe changes assigned to @Binding property by parent class in order to execute code with some side effects ! 回答1: Here is possible approach. The demo shows two-directional channel through adapter binding between main & dependent views. Due to many

问题 How can I use Binding(get: { }, set: { }) custom binding with @Binding property on SwiftUI view. I have used this custom binding successfully with @State variable but doesn't know how to apply it to @Binding in subview initializer. I need it to observe changes assigned to @Binding property by parent class in order to execute code with some side effects ! 回答1: Here is possible approach. The demo shows two-directional channel through adapter binding between main & dependent views. Due to many

问题 How can I use Binding(get: { }, set: { }) custom binding with @Binding property on SwiftUI view. I have used this custom binding successfully with @State variable but doesn't know how to apply it to @Binding in subview initializer. I need it to observe changes assigned to @Binding property by parent class in order to execute code with some side effects ! 回答1: Here is possible approach. The demo shows two-directional channel through adapter binding between main & dependent views. Due to many

问题 After spending some time creating a @Debounced property wrapper I'm not happy with the readability of the code. To understand what's going on you really need to understand how a Property wrapper works and the concept of the wrappedvalue and projectedvalue. This is the Property Wrapper: @propertyWrapper class Debounced<Input: Hashable> { private var delay: Double private var _value: Input private var function: ((Input) -> Void)? private weak var timer: Timer? public init(wrappedValue: Input,

问题 TL;DR It seems that the ContentView below evaluates the body's if statement before init has run. Is there a race condition, or is my mental model out-of-order? Kudos A shout-out to Asperi, who provided the state-initializer equivalent that solves today's problem. Code Why does ContentView display "dummy is nil"? It seems something gets closed over before the initializer sets dummy . What is it about the second assignment that fixes things? class Dummy { } struct ContentView: View { @State