我按照教程做了一切正確的事。當我嘗試設置標籤文本時,我可以在控制檯中打印出年齡,我得到一個零錯誤。嘗試連接字符串時發生nill錯誤
class ViewController: UIViewController {
@IBOutlet var inputField: UITextField!
@IBOutlet var outputLbl: UILabel!
@IBAction func enterBtn(sender: AnyObject) {
if(inputField != nil){
var age = inputField.text.toInt()
println(age)
var catYears = age! * 7
println(catYears)
outputLbl.text = "Your cat is \(catYears) old"
}
else {
outputLbl.text = "Please enter a age"
}
}
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
我閱讀了文檔,並且正確地連接了字符串。不過就像我說的那樣,當我把下面的陳述拿出來:
outputLbl.text = "Your cat is \(catYears) old"
程序運行正常。
視圖加載後,文本字段永遠不會爲零,您可能需要測試以查看輸入字段中是否有任何內容。 'if inputField.text!=「」{}' – JMFR 2015-02-24 19:51:24