【从零开始的Swift开发心路历程-Day21】简单介绍UIPickerView

今天我们要介绍UIPickerView，UIPickerView可以让你在列表中选择所需要的项目，後面有一个练习会用到UIPickerView，就让我们期待一下吧～现在先来简单介绍如何使用UIPickerView！
首先我们在storyboard里面新增UIPickerView以及等等用来显示UIPickerView值的UILabel

接着宣告一笔资料用於在UIPickerView上显示

let week = ["星期一","星期二","星期三","星期四","星期五","星期六","星期日"]

也要记得设定UIPickerView的delegate和dataSource

接着写一个extension

extension ViewController: UIPickerViewDelegate, UIPickerViewDataSource {
    // UIPickerView 有几列可以选择
    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        return 1
    }
    // UIPickerView 各列有多少行资料
    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        return week.count
    }
    // UIPickerView 每个选项显示的资料
    func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        return week[row]
    }
    // UIPickerView 改变选择後执行的动作
    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        lbl.text = week[row]
    }

}

如此一来就完成了一个简单的UIPickerView罗
执行结果如下