Question

我已经在这个问题上阅读了几个答案，但似乎找不到适用于我的代码的答案。当我分配＆＃34;文本＆＃34; ＆＃34; myLabel＆＃34; （下面）我得到：＆＃34; [UIButton setText：]：无法识别的选择器发送到实例....＆＃34;程序编译好，但遇到赋值语句时崩溃。

但是我能够分配甚至打印出同一对象的backgroundColor。关于我做错了什么想法？

// ******** 导入UIKit

class ViewController: UIViewController {

//*********  Button 1 *********//


@IBOutlet weak var lbl1: UILabel!


@IBAction func btn1(sender: AnyObject) {

    nextColorFor1++
    makeColor (self.lbl1, nextColor: nextColor1)

}

//****  Button 2  **********//


@IBOutlet weak var lbl2: UILabel!

@IBAction func btn2(sender: AnyObject) {

    nextColorFor2++
    makeColor (self.lbl2, nextColor: nextColorFor2)

}

// *********** //

func makeColor (myLabel:UILabel, nextColor:Int)
{
    switch nextColor
    {
    case 0: myLabel.backgroundColor = UIColor(red: 0.1, green: 0, blue: 0, alpha: 0.1)
    case 1: myLabel.backgroundColor = UIColor(red: 0.2, green: 0, blue: 0, alpha: 0.2)
    case 2: myLabel.backgroundColor = UIColor(red: 0.3, green: 0, blue: 0, alpha: 0.3)
    case 3: myLabel.backgroundColor = UIColor(red: 0.4, green: 0, blue: 0, alpha: 0.4)
    case 4: myLabel.backgroundColor = UIColor(red: 0.5, green: 0, blue: 0, alpha: 0.5)
    default: print("end of colors")
    }

    print(myLabel.backgroundColor)
    myLabel.text = "4"  <<< --- This is where the crask occurs
}


override func viewDidLoad() {


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

}

}

Answer 1

您似乎已将UIButton（位于故事板或xib上）与代码中的UILabel相关联，并且您正尝试将其视为标签。确保将IB上的按钮更换为标签，它将起作用。

Answer 2

不要传递局部变量

现在如果你想设置按钮的标题

func makeColor()
{
    myLabel.backgroundColor = UIColor(red: 0.1, green: 0, blue: 0, alpha: 0.1)

    print(myLabel.backgroundColor)
    myLabel.text = "4"
}

@IBAction func myButton(sender: AnyObject) {
   makeColor ()
}

Answer 3

尝试在不知道来源（xib ||故事板）的情况下缓解此错误

extension UIButton
{
    func setText(_ text: String) {
        assertionFailure("crashlytics reported Fatal Exception: NSInvalidArgumentException -[UIButton setText:]: unrecognized selector sent to instance 0xyyy objc_exception_throw        keyboard_arrow_down")
        titleLabel?.text = text
    }
}

[UIButton setText：]：发送到实例的无法识别的选择器

3 个答案: