我的视图中有两个不同的UIPickerView.当我将dataSource和委托设置为通过故事板托管的View时,它们工作得很好,但是当我尝试通过如下所述的代码执行此操作时,它不起作用.
两个选择器都应该有不同的数据来显示(甚至可能是代表的不同行为).因此,我想以编程方式将它们连接到不同的数据源.
我尝试创建自己的类,实现UIPickerViewDataSource-和UIPickerViewDelegate-Protocols,并将该类的对象连接到我的PickerViews,但它不起作用.在运行时抛出异常,终止时出现NSException类型的未捕获异常,说明：
2015-01-09 17:50:05.333 Pet Stats[4953:244338] -[NSConcreteMapTable numberOfComponentsInPickerView:]: unrecognized selector sent to instance 0x7b4616d0 2015-01-09 17:50:05.338 Pet Stats[4953:244338] *** Terminating app due to uncaught exception 'NSInvalidArgumentException',reason: '-[NSConcreteMapTable numberOfComponentsInPickerView:]: unrecognized selector sent to instance 0x7b4616d0'
我怎样才能让它发挥作用？我错过了什么？这是我的代码：
WeightWheelController.swift
import UIKit
class WeightWheelController: NSObject,UIPickerViewDelegate,UIPickerViewDataSource {
let ElementCount: Int!
init(pickerInterval: Int) {
ElementCount = pickerInterval
}
func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(pickerView: UIPickerView,numberOfRowsInComponent component: Int) -> Int {
return ElementCount
}
func pickerView(pickerView: UIPickerView,titleForRow row: Int,forComponent component: Int) -> String! {
return String(row + 1)
}
func pickerView(pickerView: UIPickerView!,didSelectRow row: Int,inComponent component: Int)
{
println("External Controller:" + String(row + 1))
}
}
WeightWheelInputViewController.swift
import UIKit
class WeightWheelInputViewController: UIViewController {
@IBOutlet weak var picker1: UIPickerView!
@IBOutlet weak var picker2: UIPickerView!
override func viewDidLoad() {
super.viewDidLoad()
//picker attached to c1 should show number from 1 to 150
let c1 = WeightWheelController(pickerInterval: 150)
//picker attached to c1 should show number from 1 to 10
let c2 = WeightWheelController(pickerInterval: 10)
picker1.dataSource = c1
picker1.delegate = c1
picker2.dataSource = c2
picker2.delegate = c2
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
}
最新消息：
在这个问题中,我发现您可以为不同的选择器视图使用不同的标签.这将是一种选择;但是,我不喜欢它.我想宁愿遵循MVC’的方法,并将不同的控制器连接到每个选择器.这有可能吗？
解决方法
委托和数据源都是无主参考.这意味着一旦你超出范围,c1和c2就会被释放.尝试将c1和c2声明为类的属性.
无主引用不会对引用的对象产生强烈保持(例如,它们不会增加保留计数以防止ARC释放引用的对象).
class WeightWheelInputViewController: UIViewController {
@IBOutlet weak var picker1: UIPickerView!
@IBOutlet weak var picker2: UIPickerView!
var c1 : WeightWheelController!
var c2 : WeightWheelController!
override func viewDidLoad() {
super.viewDidLoad()
c1 = WeightWheelController(pickerInterval: 150)
c2 = WeightWheelController(pickerInterval: 10)
picker1.dataSource = c1
picker1.delegate = c1
picker2.dataSource = c2
picker2.delegate = c2
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
}
