通过闭包传递UIPickerView行索引

import UIKit

class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
    
    let data = ["Option 1", "Option 2", "Option 3", "Option 4"]
    var selectedRow: Int?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let pickerView = UIPickerView()
        pickerView.delegate = self
        pickerView.dataSource = self
        
        // 添加闭包作为UIPickerView的回调
        pickerView.didSelectRowClosure = { [weak self] row in
            self?.selectedRow = row
            // 在闭包中可以进行其他处理，比如更新UI或调用其他方法
            self?.handleSelectedRow(row)
        }
        
        // 将UIPickerView添加到视图中
        // ...
    }
    
    // UIPickerViewDelegate和UIPickerViewDataSource的实现
    // ...
    
    func handleSelectedRow(_ row: Int) {
        // 处理选中行索引的逻辑
        // ...
    }
}

extension UIPickerView {
    typealias DidSelectRowClosure = (Int) -> Void
    
    private struct AssociatedKeys {
        static var didSelectRowClosure = "didSelectRowClosure"
    }
    
    var didSelectRowClosure: DidSelectRowClosure? {
        get {
            return objc_getAssociatedObject(self, &AssociatedKeys.didSelectRowClosure) as? DidSelectRowClosure
        }
        set {
            if let newValue = newValue {
                objc_setAssociatedObject(self, &AssociatedKeys.didSelectRowClosure, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
            }
        }
    }
    
    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        didSelectRowClosure?(row)
    }
    
    // 其他UIPickerViewDelegate和UIPickerViewDataSource的实现
    // ...
}