訪問按鈕目標拋出錯誤

Question

隨着下面的代碼，當我按下按鈕時出現錯誤。我不知道爲什麼。錯誤是無法識別的選擇器發送到實例，並終止於「終止於類型爲NSException的未捕獲異常」。任何幫助肯定是讚賞。 感謝

class WordSearchWindow: UIViewController { 

let boardsize = 10 

override func viewDidAppear(animated: Bool) { 
    super.viewDidAppear(false) 
    buttonGridder() 
} 

func buttonGridder() { 
    for x in 0..<self.boardsize { 
     for y in 0..<self.boardsize{ 
      let sizer = ButtonGrid.frame.width 
      let buttonSize:CGFloat = sizer/CGFloat(self.boardsize) 
      let letterButton = WordButton(column: x, row: y, buttonSize: buttonSize, buttonMargin: 0) 
      letterButton.addTarget(self, action: "letterFirst", forControlEvents: .TouchDown) 
      letterButton.addTarget(self, action: "letterSecond", forControlEvents: .TouchUpInside) 
      self.ButtonGrid.addSubview(letterButton) 
     } 
    } 
} 

func letterFirst(sender: WordButton) { 
    print("hello1") 
} 

func letterSecond(sender: WordButton) { 
    print("hello2") 
} 
} 

Answer 1

試試這個：

letterButton.addTarget(self, action: "letterFirst:", forControlEvents: .TouchDown) 
letterButton.addTarget(self, action: "letterSecond:", forControlEvents: .TouchUpInside) 

在行動