自定义PickerView组件封装实践

在之前的讨论中，我们已经对系统的PickerView进行了基础的介绍。虽然其使用方法相对简单，但若要创建一个功能全面且易于集成的PickerView类，则需要更多的设计与实现技巧。本文将分享我近期在一个项目中开发的PickerView类，该类不仅支持多种选择模式，还提供了简洁的API接口，便于开发者快速集成。

以下是该PickerView类的基本使用示例：

import UIKit

class ViewController: UIViewController {
    private let textPicker: JHPickerView = {
        var dataSource = [String]()
        for i in 0..<20 {
            dataSource.append("\(i)")
        }
        return JHPickerView(dataSource: dataSource, title: "单项选择")
    }()
    
    private let datePicker: JHPickerView = {
        return JHPickerView(datePickerMode: .date, title: "日期选择")
    }()
    
    private let locationPicker: JHPickerView = {
        return JHPickerView(areaType: .provinceCityDistrict, title: "地理位置选择")
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
    }
    
    @IBAction func textPickerButtonTapped(_ sender: UIButton) {
        textPicker.show()
        textPicker.selectRow(at: 3, animated: true)
        textPicker.OnDoneSelection= { selectedRow, result in
            print("Selected Row: \(selectedRow)")
            print("Result: \(result)")
            sender.setTitle(result, for: .normal)
        }
        textPicker.OnCancel= {
            print("Picker dismissed")
        }
    }
    
    @IBAction func datePickerButtonTapped(_ sender: UIButton) {
        datePicker.show()
        datePicker.setDate(Date(), animated: true)
        datePicker.onDoneSelectionWithFormat("yyyy-MM-dd") { selectedDate, dateString in
            print("Selected Date: \(selectedDate)")
            print("Date String: \(dateString)")
            sender.setTitle(dateString, for: .normal)
        }
        datePicker.OnCancel= {
            print("Picker dismissed")
        }
    }
    
    @IBAction func locationPickerButtonTapped(_ sender: UIButton) {
        locationPicker.show()
        locationPicker.OnDoneSelection= { province, city, district in
            print("Province: \(province ?? "")")
            print("City: \(city ?? "")")
            print("District: \(district ?? "")")
            sender.setTitle((province ?? "") + (city ?? "") + (district ?? ""), for: .normal)
        }
        locationPicker.OnCancel= {
            print("Picker dismissed")
        }
    }
}

上述代码展示了如何通过初始化不同的参数来创建不同类型的PickerView，并通过闭包回调处理用户的选择结果。每个PickerView实例都提供了显示、选择特定项以及取消操作的方法，方便开发者根据实际需求进行调用。

完整代码及更多示例请参考代码链接。