swiftui

问题 I have something like this: struct SomeView: View { @ObservedObject var viewModel: SomeViewModel var body: some View { NavigationView { // <- culprit Button(action: { self.viewModel.logOut() }) { Text("X").frame(width: 40, height: 40) } } } class SomeViewModel: ObservableObject { func logOut() { // changes global state, based on which the views are swapped, so `SomeView` is removed and replaced by a different one } } When the button is pressed, SomeView is closed and a different view is

问题 I've added a .toolbar to the top level of a NavigationView that will eventually be used to select items in a list without using swipe gestures (up button, down button, etc.). I also have a .navigationBar going on, to access other views for Account and Settings. For the most part it's looking really good, but when I follow a NavigationLink (in .navigationBarItems) within NavigationView, and then use the built-in back navigation , my .toolbar disappears from the top level. Am I putting the

问题 I have the following timer: struct ContentView: View { @State var timeRemaining = 10 let timer = Timer.publish(every: 1, on: .main, in: .common).autoconnect() var body: some View { NavigationView{ VStack { if(self.timeRemaining > 0) { Text("\(timeRemaining)") .onReceive(timer) { _ in if self.timeRemaining > 0 { self.timeRemaining -= 1 } } } else { Text("Time is up!") } } } } } If I remove the NavigationView view, the timer updates and works, but like that it doesn't, what's going on here and

问题 I have the following timer: struct ContentView: View { @State var timeRemaining = 10 let timer = Timer.publish(every: 1, on: .main, in: .common).autoconnect() var body: some View { NavigationView{ VStack { if(self.timeRemaining > 0) { Text("\(timeRemaining)") .onReceive(timer) { _ in if self.timeRemaining > 0 { self.timeRemaining -= 1 } } } else { Text("Time is up!") } } } } } If I remove the NavigationView view, the timer updates and works, but like that it doesn't, what's going on here and

问题 This is maybe related to the new (12.3) version of XCode that came out recently but I have a very simple SwiftUI View: import SwiftUI struct HomeView: View { var body: some View { NavigationView { Text("Text") .navigationBarTitle("My Title") } } } And I'm getting this warning in the console: 2020-12-15 18:25:06.506062-0800 Shopmatic[46177:9585655] [LayoutConstraints] Unable to simultaneously satisfy constraints. Probably at least one of the constraints in the following list is one you don't

问题 Have some rendered image and need to determine tap position relative to image. Seems to be simple, but can't find the answer var body: some View { VStack { Image(uiImage: drawRectangle()) // some rendered image .onTapGesture { // print(x, y)? } 回答1: Found this solution: .gesture( DragGesture(minimumDistance: 0, coordinateSpace: .global) .onChanged { value in self.position = value.location } .onEnded { _ in self.position = .zero } ) setting minimumDistance: 0 will call onChanged immediately

问题 I have created an ObservableObject in a View. @ObservedObject var selectionModel = FilterSelectionModel() I put a breakpoint inside the FilterSelectionModel 's init function and it is called multiple times. Because this View is part of a NavigationLink , I understand that it gets created then and along with it, the selectionModel. When I navigate to the View, the selectionModel is created again. In this same View I have a "sub View" where I pass the selectionModel as an EnvironmentObject so

问题 Does anyone know how to change the background colour of a tabbed view bottom bar? I have set the accent colour which changed the colour of my icons when I select each tab bar item. I have tried setting the background to a colour but it doesn't change the back, and tried setting background to an image just to be sure but that also doesn't do anything. Wondering if I need to specifically access the bottom bar somehow and then set a property on that? 回答1: Here is a solution. You can change

问题 Does anyone know how to change the background colour of a tabbed view bottom bar? I have set the accent colour which changed the colour of my icons when I select each tab bar item. I have tried setting the background to a colour but it doesn't change the back, and tried setting background to an image just to be sure but that also doesn't do anything. Wondering if I need to specifically access the bottom bar somehow and then set a property on that? 回答1: Here is a solution. You can change

问题 Just playing with Swift UI basic app and the preview canvas is not showing even though I'm in canvas mode. App runs, and I have this little snippet what am I missing? #if DEBUG struct ContentView_Previews : PreviewProvider { static var previews: some View { ContentView() } } #endif 回答1: To preview and interact with views from the canvas in Xcode, ensure your Mac is running on Catalina MacOS . https://developer.apple.com/tutorials/swiftui/creating-and-combining-views Please check apple