SwiftUI - How can I call a Function in my View?

Question

I am using SwiftUI/Swift for a week now, and I love it. Now I have a problem. I want to call a Function from my View, but I get this Error

Type '()' cannot conform to 'View'; only struct/enum/class types can conform to protocols

This is the Code:

struct testView: View {
    
    
    var body: some View {
        VStack {
            Text("TextBox")
            Text("SecondTextBox")
            self.testFunction()
        }
    }
    
    func testFunction() {
        print("This is a Text.")
    }
    
}

I don't get it. In other languages its much simpler and could work that way. Can anybody help me please? Swift is pretty new to me :D

Answer 1

Meanwhile here are the places (not all) where/how you can call a function

    init() {
        self.testFunction()     // non always good, but can
    }

    var body: some View {
        self.testFunction()            // 1)
        return VStack {
            Text("TextBox")
               .onTapGesture {
                  self.testFunction()    // 2)
               }
            Text("SecondTextBox")
        }
        .onAppear {
            self.testFunction()     // 3)
        }
        .onDisappear {
            self.testFunction()     // 4)
        }
    }

... and so on

Answer 2

Using Swift 5.3 and Xcode 12.4

I use a little extension to debug inside the Views (VStack in the example), e.g. to inspect a geometryReader.size. It could be used to call any function in the View as follows:

NOTE: For debugging purposes only. I don't recommend including code like this in any production code

VStack {
    Text.console("Hello, World")
    Text("TEXT"
}

extension Text {
    static func console<T>(_ value: T) -> EmptyView {
        print("\(value)")
        return EmptyView()
    }
}

This will print "Hello, World" to the console.....