主页 / coding / 问题 / 77560351
Accepted
Eduard Unruh
Asked: 2023-11-28 06:40:55 +0800 CST

SwiftUI - PreviewProvider 为可选的 Void 函数传递 nil

  • 772
struct Toolbar: View {
    
    let closeThisView: () -> Void?
    var toolbarTitle: String
    
    var body: some View {
        
        Text("bla")
    }
}


struct Toolbar_Previews: PreviewProvider {
    
    static var previews: some View {
        Toolbar(closeThisView: nil, toolbarTitle: "comments")
            .preferredColorScheme(.dark)
    }
}

nil既然我在预览中不需要它，我怎样才能传递它或任何函数？就像这就是我也尝试过的：

struct Toolbar_Previews: PreviewProvider {
    
    @Environment(\.dismiss) var dismiss
    func closeThisView(){

        DispatchQueue.main.async {
            self.dismiss()
        }
    }
    
    static var previews: some View {
        Toolbar(closeThisView: closeThisView, toolbarTitle: "comments")
            .preferredColorScheme(.dark)
    }
}
swift

2 个回答

  1. Best Answer

    您可以使用这个 { } 例如：

    struct Toolbar_Previews: PreviewProvider {
    
   static var previews: some View {
        Toolbar(closeThisView: {}, toolbarTitle: "comments")
            .preferredColorScheme(.dark)
    }
}
    • 0

  2. 如果您希望能够在初始化程序中排除它，您可以执行以下操作：

    
struct Toolbar: View {
    var closeThisView: (() -> Void)? = nil
    var toolbarTitle: String
    
    var body: some View {
        Text("bla")
    }
}

struct Toolbar_Previews: PreviewProvider {  
    static var previews: some View {
        Toolbar(toolbarTitle: "comments")
            .preferredColorScheme(.dark)
    }
}
    • 0

相关问题