SwiftUI-从未在UIViewRepresentable自定义选择器视图中调用过UITableView cellForRowAtIndexPath

Question

我正在尝试使用UIViewRepresentable将此picker view中的GitHub repo合并到我的SwiftUI项目中。

我创建了一个测试项目来说明我遇到的问题。以下是构建项目所需的代码（不包括PickerView，我是从here中提取的）。

型号

struct Fruit {
    let name: String
    let isInStock: Bool

    static let apple = Fruit(name: "apple", isInStock: true)
    static let orange = Fruit(name: "orange", isInStock: true)
    static let banana = Fruit(name: "banana", isInStock: true)
    static let raspberry = Fruit(name: "raspberry", isInStock: false)
    static let blueberry = Fruit(name: "blueberry", isInStock: false)
    static let lemon = Fruit(name: "lemon", isInStock: true)
    static let lime = Fruit(name: "lime", isInStock: false)
}

ContentView

struct ContentView: View {
    @State private var fruits: [Fruit] = [.apple, .orange, .banana, .raspberry, .blueberry, .lemon, .lime]
    @State private var selectedFruit: Fruit = .apple

    var body: some View {
        FruitPicker(fruits: self.$fruits, selectedFruit: self.$selectedFruit)
    }
}

FruitPicker

struct FruitPicker: UIViewRepresentable {
    @Binding var fruits: [Fruit]
    @Binding var selectedFruit: Fruit

    class Coordinator: NSObject, PickerViewDelegate, PickerViewDataSource {
        @Binding var fruits: [Fruit]
        @Binding var selectedFruit: Fruit

        init(fruits: Binding<[Fruit]>, selectedFruit: Binding<Fruit>) {
            self._fruits = fruits
            self._selectedFruit = selectedFruit
        }

        func pickerViewNumberOfRows(_ pickerView: PickerView) -> Int {
            return self.fruits.count
        }

        func pickerViewHeightForRows(_ pickerView: PickerView) -> CGFloat {
            return 50
        }

        func pickerView(_ pickerView: PickerView, titleForRow row: Int) -> String {
            return self.fruits[row].name
        }

        func pickerView(_ pickerView: PickerView, didSelectRow row: Int) {
            self.selectedFruit = self.fruits[row]
        }
    }

    func makeCoordinator() -> FruitPicker.Coordinator {
        return Coordinator(fruits: self.$fruits, selectedFruit: self.$selectedFruit)
    }

    func makeUIView(context: UIViewRepresentableContext<FruitPicker>) -> PickerView {
        let pickerView = PickerView()

        pickerView.delegate = context.coordinator
        pickerView.dataSource = context.coordinator

        return pickerView
    }

    func updateUIView(_ pickerView: PickerView, context: UIViewRepresentableContext<FruitPicker>) {

    }
}

PickerView使用UITableView模仿UIPickerView的功能，但外观平坦。

运行项目时，UITableViewDelegate和UITableViewDataSource的{​​{1}}中的PickerView.swift和heightForRowAtIndexPath方法都被调用，但是numberOfRowsInSection不是。

我首先尝试从“调试”选项卡中选择“调试视图层次结构”，但是每次执行Xcode都会崩溃。因此，我随后设置了背景颜色，以查看选择器视图是否完全出现在屏幕上，而实际上没有，因此我在cellForRowAtIndexPath和makeUIView内放置断点以检查updateUIView帧。在两种情况下，它都返回零。我尝试在PickerView中为选择器视图设置框架，但没有任何变化-makeUIView根本不会被调用。

有人对我要去哪里错或者到底是什么导致cellForRowAtIndexPath永远不会被叫有任何想法吗？