SwiftUI ObservedObject如何轉換爲Binding （教程含源碼） 實戰需求 基礎知識 實戰代碼 加入我們一起學習SwiftUI

實戰需求

SwiftUI ObservedObject如何轉換爲Binding

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基礎知識

ObservableObject

具有發佈者的一種對象，該對象在更改對象之前發出。

protocol ObservableObject : AnyObject

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總覽
默認情況下，合成器將在其任何屬性更改之前發出更改後的值的發佈程序。

class Contact: ObservableObject {
    @Published var name: String
    @Published var age: Int

    init(name: String, age: Int) {
        self.name = name
        self.age = age
    }

    func haveBirthday() -> Int {
        age += 1
        return age
    }
}

let john = Contact(name: "John Appleseed", age: 24)
cancellable = john.objectWillChange
    .sink { _ in
        print("\(john.age) will change")
}
print(john.haveBirthday())
// Prints "24 will change"
// Prints "25"

實戰代碼

struct ContentView: View {
    @StateObject var dataModel = DataModel()

    var body: some View {
        DataView(dataModel: dataModel)
    }
}

struct DataView: View {
    @ObservedObject var dataModel: DataModel

    var body: some View {
        Text(dataModel.data)
            .padding()
    }
}

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