Question

这些都是代码。

SurveyQuestion类

class SurveyQuestion: ObservableObject {
    @Published var text: String

    init() {
        print("Initialising now ...")
        self.text = "HELLO"
        changeText()
    }

    func changeText() {
        print("Changing Text Now from \(text).. ")

        if self.text == "HELLO"{
            self.text = "BYE"
        }
        else{
            self.text = "HELLO"
        }


        print("to \(self.text) \n")


    }
}

SubView.swift

struct SubView: View {

    @ObservedObject var someOtherClass = SurveyQuestion()

    var body: some View {
        Text("Text now is \(someOtherClass.text)")

    }
}

ContentView.swift

struct ContentView: View {

    @ObservedObject var someClass = SurveyQuestion()



    var body: some View {

        VStack{

            Button(action: {
                print("Changing Text Now !")
                self.someClass.changeText()
            }) {
                Text("Change Text ")
            }

            Text("Text now is \(someClass.text)")

            SubView()

        }
    }
}

每当我单击“ changeText”按钮时，它都会更改Text（“ Text now is（someClass.text）”）中的文本，而不是Subview（）。它们都应使用相同的文本更改进行更新。知道这里出了什么问题吗？

Answer 1

您的df1 = df1[df1.columns.interseciton(['Date', 'Amount', 'Name'],sort= False)] df2 = df2[df2.columns.interseciton(['Date', 'Amount', 'Name'],sort= False)] df3 = df3[df3.columns.interseciton(['Date', 'Amount', 'Name'],sort= False)] df4 = df4[df4.columns.interseciton(['Date', 'Amount', 'Name'],sort= False)] ***Few line of code*** list_df = [df1, df2, df3, df4] for df in list_df: df = df.columns.to_series().map(col_fullform)和someClass是两个完全不同的对象。改变一个对另一个没有影响。如果假设这是一个可观察到的同时可以影响不同视图的情况，则您需要一个 environment 对象。

Answer 2

要使其正常工作，您应该使用ObservableObject的相同实例，如下所示

struct SubView: View {
    @ObservedObject var someOtherClass: SurveyQuestion // to be injected

    var body: some View {
        Text("Text now is \(someOtherClass.text)")

    }
}


struct ContentView: View {
    @ObservedObject var someClass = SurveyQuestion() // created

    var body: some View {

        VStack{

            Button(action: {
                print("Changing Text Now !")
                self.someClass.changeText()
            }) {
                Text("Change Text ")
            }

            Text("Text now is \(someClass.text)")

            SubView(someOtherClass: someClass) // << injected

        }
    }
}

当通过@Published在类中更改属性值时，某些ObservedObjects是否会更新？

2 个答案: