引用现有变量时出现 Swift 编译器错误 [重复]

Question

我正在尝试为 UITextView 手动创建一些占位符文本，当我尝试设置占位符文本时，我收到 Swift 编译器错误。 Xcode 告诉我它需要一个 pinContent 声明，我首先尝试设置它的文本值。这是我的代码：

class FirstViewController: UIViewController {

@IBOutlet var pinTitle: UITextField!

@IBOutlet var pinContent: UITextView!

@IBAction func createPin(sender: AnyObject) {



}

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

    println(userLocation)
}

// Manually create a placeholder for the text view
pinContent.text = "Description" // This line is where I get my error
pinContent.textColor = UIColor.lightGrayColor()

// Change the text properties of the text view when the user begins editing, so it types in the normal black font
func textViewDidBeginEditing(textView: UITextView) {
    if textView.textColor == UIColor.lightGrayColor() {
        textView.text = nil
        textView.textColor = UIColor.blackColor()
    }
}

// If the user leaves the text view blank when they're done editing, re-set the placeholder
func textViewDidEndEditing(textView: UITextView) {
    if textView.text.isEmpty {
        textView.text = "Description" // Sometimes I get the same error here as well
        textView.textColor = UIColor.lightGrayColor()
    }
}

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


}

Answer 1

问题似乎是您想将文本设置在方法或闭包的范围之外。
试试这个：

override func viewDidLoad() {
    super.viewDidLoad()

    // Do any additional setup after loading the view, typically from a nib.
    // Manually create a placeholder for the text view

    pinContent.text = "Description" // This line is where I get my error
    pinContent.textColor = UIColor.lightGrayColor()
    println(userLocation)
}