Swift PickerView标签错误

Question

import UIKit

类ViewController：UIViewController，UIPickerViewDataSource，UIPickerViewDelegate {@IBOutlet变量选择器：UIPickerView！ @IBOutlet var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"


}

}

您能告诉我错误行与上面我用于标题的行之间的区别吗？

为什么我会为最底层的错误。 我认为我正确声明。

Answer 1

（我假设您希望用户点击按钮时更改标签的文本）

该函数在pickerView的值更改后运行（您尝试使用的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，您还想创建一个全局变量，以便可以在IBAction函数中使用row （didSelectRow函数中的row参数只能在该函数内部使用）。

因此，将这部分代码添加到类定义下-

var rowSelected = 0

接下来，将此功能添加到您的代码中-

 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）。

因此，您的整个代码应如下所示：

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
}

希望能解决。