Swiftui 缺少参数'的参数;查看调用';随时待命
我很难理解为什么在调用此视图时必须给出名为vm的弹出视图依赖项,因为它是可观察的Swiftui 缺少参数'的参数;查看调用';随时待命,swiftui,observedobject,Swiftui,Observedobject,我很难理解为什么在调用此视图时必须给出名为vm的弹出视图依赖项,因为它是可观察的 struct ContentView: View { @State private var showPopup1 = false var body: some View { VStack { Button(action: { withAnimation { self.showPopup1.toggle()}}){
struct ContentView: View {
@State private var showPopup1 = false
var body: some View {
VStack {
Button(action: { withAnimation { self.showPopup1.toggle()}}){
Text("showPopup1") }
Text("title")
DetailView() /// this line shows error
}
}
}
struct DetailView:View {
@ObservedObject var vm:ViewModel
var body : some View {
Text("value from VM")
}
}
class ViewModel: ObservableObject {
@Published var title:String = ""
}
在初始化视图时,必须设置vm属性。这是通常的方式
struct ContentView: View {
@State private var showPopup1 = false
var body: some View {
VStack {
Button(action: { withAnimation { self.showPopup1.toggle()}}){
Text("showPopup1") }
Text("title")
DetailView(vm: ViewModel()) // Initiate your ViewModel() and pass it as DetailView() parameter
}
}
}
struct DetailView:View {
var vm: ViewModel
var body : some View {
Text("value from VM")
}
}
class ViewModel: ObservableObject {
@Published var title:String = ""
}
或者可以使用@EnvironmentObject。您必须将.environmentObject(yourObject)传递给要在其中使用对象的视图,但同样,在传递它之前,您必须对其进行初始化
顺便说一句,我不确定这是否是一个好方法,因为您在上声明了.environmentObject的视图的所有子视图都可以访问environmentObject,并且您通常只需要一个视图模型来访问一个视图
struct ContentView: View {
@State private var showPopup1 = false
var body: some View {
VStack {
Button(action: { withAnimation { self.showPopup1.toggle()}}){
Text("showPopup1") }
Text("title")
DetailView().environmentObject(ViewModel()) // Pass your ViewModel() as an environmentObject
}
}
}
struct DetailView:View {
@EnvironmentObject var vm: ViewModel // you can now use your vm, and access it the same say in all childs view of DetailView
var body : some View {
Text("value from VM")
}
}
class ViewModel: ObservableObject {
@Published var title:String = ""
}
您能否分享关于“要不设置@ObservedObject,您必须在它的某个祖先处传递一个.environmentObject(yourObject)”的示例代码