当 ObservedObject 在其他类中发生更改时如何在 ContentView 中运行方法 [Swift 5 iOS 13.4]

Posted 2023-02-26

【中文标题】当 ObservedObject 在其他类中发生更改时如何在 ContentView 中运行方法 [Swift 5 iOS 13.4]

【英文标题】：How to run a method in ContentView when an ObservedObject changes in other class [Swift 5 iOS 13.4]

【发布时间】：2020-04-09 08:10:33

【问题描述】：

这是我的基本内容视图

struct ContentView: View

    @ObservedObject var model = Model()

    init(model: Model)
    
        self.model = model
    

    // How to observe model.networkInfo's value over here and run "runThis()" whenever the value changes?

    func runThis()
    
        // Function that I want to run
    

    var body: some View
    
        VStack
            
            // Some widgets here
            
        
    

这是我的模型

class Model: ObservableObject

    @Published var networkInfo: String
    
        didSet
            
                // How to access ContentView and run "runThis" method from there?
            
    

我不确定它是否可以访问？或者如果我可以从 View 观察 ObservableObject 的变化并运行任何方法？

提前致谢！

【参考方案1】：

有很多方法可以做到这一点。如果你想 runThis() 当 networkInfo 发生变化，那么你可以使用这样的东西：

class Model: ObservableObject 
    @Published var networkInfo: String = "" 



struct ContentView: View 
@ObservedObject var model = Model()

var body: some View 
    VStack 
        Button(action: 
            self.model.networkInfo = "test"
        ) 
            Text("change networkInfo")
        
    .onReceive(model.$networkInfo)  _ in self.runThis() 
   

func runThis() 
      print("-------> runThis")
 
  

另一种全局方式是这样的：

 class Model: ObservableObject 
   @Published var networkInfo: String = "" 
    didSet 
        NotificationCenter.default.post(name: NSNotification.Name("runThis"), object: nil)
    



 struct ContentView: View 
@ObservedObject var model = Model()

var body: some View 
    VStack 
        Button(action: 
            self.model.networkInfo = "test"
        ) 
            Text("change networkInfo")
        
    .onReceive(
    NotificationCenter.default.publisher(for: NSNotification.Name("runThis")))  _ in
        self.runThis()
    
   

func runThis() 
      print("-------> runThis")
 
 

【讨论】：

这实际上很有帮助。非常感谢@workingdog，因为你，我现在将更多地了解有用的 onReceive() ！！！