observedobject

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 am currently working with SwiftUI and CoreData . Situation: I have a User Detail View with a Delete Button at the Bottom. When pressed, the Core Data Entry of the User is getting deleted and the App Navigation goes back to the Root Navigation View, which is a List of all Users. Problem: Every Time the Delete Button is clicked the App crashes with the following Error Message : *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[User timeCreated]:

问题 i am currently working with SwiftUI and CoreData . Situation: I have a User Detail View with a Delete Button at the Bottom. When pressed, the Core Data Entry of the User is getting deleted and the App Navigation goes back to the Root Navigation View, which is a List of all Users. Problem: Every Time the Delete Button is clicked the App crashes with the following Error Message : *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[User timeCreated]:

问题 I have a state called time @State var time = 0 and an ObservedObject called timerWrapper @ObservedObject var timerWrapper = TimerWrapper() time can be updated from a child view and I want to be also able to update it using the timerWrapper (theObservedObject), if I use this: self.time = self.timerWrapper.remainingSeconds and do this: Text($time) The text doesn’t update. It only works if I do this: Text(self.timerWrapper.remainingSeconds) I know that’s because when remainingSeconds is

问题 When I Googled "State vs ObservedObject" the first result was from Hacking with Swift and it said about @ObservedObject : This is very similar to @State except now we’re using an external reference type rather than a simple local property like a string or an integer. Can I use @ObservedObject to create persisted state? Is it as simple as @State is for simple properties and @ObservedObject is for complex objects , or is there more nuance to it? 回答1: @ObservedObject does not persist state Can I

问题 When I Googled "State vs ObservedObject" the first result was from Hacking with Swift and it said about @ObservedObject : This is very similar to @State except now we’re using an external reference type rather than a simple local property like a string or an integer. Can I use @ObservedObject to create persisted state? Is it as simple as @State is for simple properties and @ObservedObject is for complex objects , or is there more nuance to it? 回答1: @ObservedObject does not persist state Can I

问题 This one I've been researching for a few days, scouring the Swift & SwiftUI docs, SO, forums, etc. and can't seem to find an answer. Here is the problem; I have a SwiftUI custom View that does some state determination on a custom API request class to a remote resource. The View handles showing loading states and failure states, along with its body contents being passed through via ViewBuilder so that if the state from the API is successful and the resource data is loaded, it will show the