快速PickerView标签错误

Question

import UIKit

类ViewController: UIViewController，UIPickerViewDataSource，UIPickerViewDelegate { @IBOutlet选择器: UIPickerView！@IBOutlet标签: UILabel！

var Array = ["Iphone", "겔럭시", "베가아이언"]

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    picker.delegate = self
    picker.dataSource = self

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! {
    return Array[row]
}
func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    return Array.count
}

func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
    return 1
}
@IBAction func buttonTapped(sender: AnyObject) {
                    label.text = Array[row]       ///this part error "use of unresolved identifier row"


}

}

你能向我解释一下我在上面标题中使用的错误行和行之间的区别吗？

为什么我会得到错误的底部一个。我想我声明是正确的。

Answer 1

(我假设您希望在用户点击按钮时更改标签的文本)

此函数在选择器视图的值发生更改时运行(您试图使用的row参数，在创建pickerView时运行，而不是在值更改时运行)-

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

另外，您希望创建一个全局变量，以便在您的row函数中使用row ( didSelectRow函数中的row参数只能在该函数中使用)。

所以在类定义下添加这段代码-

var rowSelected = 0

接下来，将这个函数添加到代码中-

 func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
      rowSelected = row
}

最后，将label.text = Array[row]更改为label.text = Array[rowSelected](这也会使未解决的标识符错误消失)。

所以你的代码应该是这样的-

var rowSelected = 0
var Array = ["Iphone", "겔럭시", "베가아이언"]

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    picker.delegate = self
    picker.dataSource = self

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! {
    return Array[row]
}
func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    return Array.count
}

func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
    return 1
}
@IBAction func buttonTapped(sender: AnyObject) {
       label.text = Array[rowSelected]


}
func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
      rowSelected = row
}

希望这能成功。