1，选择框可以让用户以滑动的方式选择值。示例如下：
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import UIKit
class ViewController:UIViewController, UIPickerViewDelegate, UIPickerViewDataSource{
var pickerView:UIPickerView!
override func viewDidLoad() {
super.viewDidLoad()
pickerView=UIPickerView()
//将dataSource设置成自己
pickerView.dataSource=self
//将delegate设置成自己
pickerView.delegate=self
//设置选择框的默认值
pickerView.selectRow(1,inComponent:0,animated:true)
pickerView.selectRow(2,inComponent:1,animated:true)
pickerView.selectRow(3,inComponent:2,animated:true)
self.view.addSubview(pickerView)
//建立一个按钮，触摸按钮时获得选择框被选择的索引
var button=UIButton(frame:CGRectMake(0,0,100,30))
button.center=self.view.center
button.backgroundColor=UIColor.blueColor()
button.setTitle("获取信息",forState:.Normal)
button.addTarget(self, action:"getPickerViewValue",
forControlEvents: UIControlEvents.TouchUpInside)
self.view.addSubview(button)
}
//设置选择框的列数为3列,继承于UIPickerViewDataSource协议
func numberOfComponentsInPickerView( pickerView: UIPickerView) -> Int{
return 3
}
//设置选择框的行数为9行，继承于UIPickerViewDataSource协议
func pickerView(pickerView: UIPickerView,numberOfRowsInComponent component: Int) -> Int{
return 9
}
//设置选择框各选项的内容，继承于UIPickerViewDelegate协议
func pickerView(pickerView:UIPickerView!,titleForRow row: Int,forComponent component: Int)
-> String!{
return String(row)+"-"+String(component)
}
//触摸按钮时，获得被选中的索引
func getPickerViewValue(){
var alertView=UIAlertView();
alertView.title="被选中的索引为"
alertView.message=String(pickerView.selectedRowInComponent(0))+"-"+String(pickerView!.selectedRowInComponent(1))+"-"+String(pickerView.selectedRowInComponent(2))
alertView.addButtonWithTitle("OK")
alertView.show()
}
} |
2，调整选择框的尺寸
UIPickerView用frame和center两个属性设置整个选择框的大小和位置。
如果要调整内部列的宽度，需要实现UIPickerViewDelegate协议类中pickerView:widthForComponent方法设置
如果要调整内部行高，则需要实习上述协议类中pickerView:rowHeightForComponent方法设置
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//设置列宽func pickerView(pickerView: UIPickerView！,widthForComponent component: Int) -> CGFloat{
if(00 == component){
//第一列变宽
return 100
}else{
//第二、三列变窄
return 30
}
}//设置行高func pickerView(pickerView: UIPickerView！,rowHeightForComponent component: Int) -> CGFloat{
return 50
} |
3，将图片作为选择框选项
选择框选项的内容，除了可以使字符串类型的，还可以是任意UIView类型的元素。比如我们将选项内容设置为图片：
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func pickerView(pickerView:UIPickerView!,viewForRow row: Int,forComponent component: Int,
reusingView view:UIView!) -> UIView!{
var image = UIImage(named:"icon_"+String(row))
var imageView = UIImageView()
imageView.image = image
return imageView
} |
4，检测响应选项的选择状态
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func pickerView(pickerView: UIPickerView！,didSelectRow row: Int, inComponent component: Int){
//将在滑动停止后触发，并打印出选中列和行索引
println(component)
println(row)
} |