SwiftUI: ViewModifier

protocol ViewModifier

应用于视图或另一个视图修改器的修改器，产生原始值的不同版本。

struct BorderedCaption: ViewModifier{
    func body(content: Content) -> some View {
        content
            .font(.caption2)
            .padding(10)
            .overlay {
                RoundedRectangle(cornerRadius: 15)
                    .stroke(lineWidth: 1)
            }
            .foregroundColor(.blue)
        
    }
}

extension View{
    func borderedCaption() -> some View {
        modifier(BorderedCaption())
    }
}

struct ContentView1: View {
    var body: some View{
        Image(systemName: "bus")
            .resizable()
            .frame(width:50, height:50)
        Text("Downtown Bus")
            .borderedCaption()
    }
}

SwiftUI-View-ViewModifier@2x.png