iOS学习十二之选择器控件UIPickerView

UIPickerView是一个简易的列表控件，用于提供有限个数的选项供用户选择。

它是通过代理和数据源的方法对其进行设置和数据源填充的，这种控件的设计模式也是代理模式的应用之一。

添加下面的代码即可实现基本功能。

class ViewController: UIViewController,UIPickerViewDelegate,UIPickerViewDataSource {

override func viewDidLoad() {

super.viewDidLoad()

// Do any additional setup after loading the view, typically from a nib.

let picker = UIPickerView(frame:CGRect(x:20, y:100, width:500, height:150))

picker.delegate = self

picker.dataSource = self

self.view.addSubview(picker)

}

//设置视图的分区数，也可以理解为选择列表的列数

func numberOfComponents(in pickerView: UIPickerView) -> Int {

return 2

}

//设置每个分区的行数，参数component用于判断具体的分区

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {

return 8

}

//返回设置列表中每一行的数据，参数row和component分别用于区分行和列

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {

return "\(component)area\(row)line data"

}

//返回值设置具体行的行高

func pickerView(_ pickerView: UIPickerView, rowHeightForComponent component: Int) -> CGFloat {

return 50

}

//返回值设置分区的宽度，即列的宽度

func pickerView(_ pickerView: UIPickerView, widthForComponent component: Int) -> CGFloat {

return 200

}

//选中数据时的回调代理

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {

print("\(component)area\(row)line data")

}