Swift 正在从ObserveObject发布服务器更新状态
我曾尝试使用Combine和SwiftUI,但仍停留在更新状态中基本上我想在每次ObservieObject更改时更新视图中的状态, 下面是一个例子Swift 正在从ObserveObject发布服务器更新状态,swift,swiftui,reactive-programming,swift5,Swift,Swiftui,Reactive Programming,Swift5,我曾尝试使用Combine和SwiftUI,但仍停留在更新状态中基本上我想在每次ObservieObject更改时更新视图中的状态, 下面是一个例子 class XViewModel: ObservableObject { @Published var tVal: Bool = false private var cancellables = Set<AnyCancellable>() func change() { Just(true)
class XViewModel: ObservableObject {
@Published var tVal: Bool = false
private var cancellables = Set<AnyCancellable>()
func change() {
Just(true)
.delay(for: 3.0, scheduler: RunLoop.main)
.receive(on: RunLoop.main)
.assign(to: \.tVal, on: self)
.store(in: &self.cancellables)
}
}
但看起来,虽然所有的东西都更新了,但它并没有更新状态。是否有任何方法可以更新状态,或者它根本就不需要更新,我需要将我的视图直接绑定到viewModel的tVal值,即publisher
谢谢。在
初始化
中,@状态
尚未准备好操作,请使用.onReceive
,如下所示
struct ContentView: View {
@ObservedObject var viewModel = XViewModel()
@State var toggleVal: Bool = false
private var cancellables = Set<AnyCancellable>()
init() {
self.viewModel.$tVal
.sink { newVal in
print(newVal)
}
.store(in: &cancellables)
viewModel.change()
}
var body: some View {
VStack {
Toggle(isOn: self.$viewModel.tVal) {
Text("Toggle")
Toggle(isOn: self.$toggleVal) {
Text("Toggle from View")
}
.onReceive(self.viewModel.$tVal) { newVal in // << here !!
self.toggleVal = newVal
}
}
}
struct ContentView:View{
@ObservedObject var viewModel=XViewModel()
@状态变量toggleVal:Bool=false
private var cancelables=Set()
init(){
self.viewModel.$tVal
.sink{newVal in
打印(newVal)
}
.store(在:&可取消项中)
viewModel.change()
}
var body:一些观点{
VStack{
切换(isOn:self.$viewModel.tVal){
文本(“切换”)
切换(isOn:self.$toggleVal){
文本(“从视图切换”)
}
.onReceive(self.viewModel.tVal){newVal in//谢谢,是的,我知道状态尚未初始化
viewModel.Just triggers
viewModel.tVal publisher triggers
view.toggleVal state triggers
updates UI
struct ContentView: View {
@ObservedObject var viewModel = XViewModel()
@State var toggleVal: Bool = false
private var cancellables = Set<AnyCancellable>()
init() {
self.viewModel.$tVal
.sink { newVal in
print(newVal)
}
.store(in: &cancellables)
viewModel.change()
}
var body: some View {
VStack {
Toggle(isOn: self.$viewModel.tVal) {
Text("Toggle")
Toggle(isOn: self.$toggleVal) {
Text("Toggle from View")
}
.onReceive(self.viewModel.$tVal) { newVal in // << here !!
self.toggleVal = newVal
}
}
}