SwiftUI OnDrop 函数取决于条件

Question

我们在 SwiftUI 中为 MacOS 应用程序使用 OnDrop() 函数。它真的很棒。但是，我只想在特殊情况下允许 onDrop 函数。我尝试仅在该条件为真时才在 onDrag 之后执行代码，效果很好。但是，仍然存在不应该可见的拖动动画/鼠标拖动效果。

这是我们正在使用的代码:

.onDrop(of: [“public.file-url”], isTargeted: $userData.shopPopOver) { providers -> Bool in
for provider in providers
{

我可以只在条件下添加 .onDrop 吗？只是为了展示一个例子，这肯定是行不通的:

if (condition)
{
.onDrop(of: [“public.file-url”], isTargeted: $userData.shopPopOver) { providers -> Bool in

提前致谢!

Answer 1

这是可用于描述的用例的自定义修饰符

struct Droppable: ViewModifier {
    let condition: Bool
    let types: [String]
    let tracking: Binding<Bool>?
    let action: ([NSItemProvider]) -> Bool

    @ViewBuilder
    func body(content: Content) -> some View {
        if condition {
            content.onDrop(of: types, isTargeted: tracking, perform: action)
        } else {
            content
        }
    }
}

extension View {
    public func acceptDrop(if condition: Bool, of supportedTypes: [String], isTargeted: Binding<Bool>?, perform action: @escaping ([NSItemProvider]) -> Bool) -> some View {
        self.modifier(Droppable(condition: condition, types: supportedTypes, tracking: isTargeted, action: action))
    }
}