UIButton addTarget Self是如何工作的？

问题描述

我尝试找出为什么self指向GameViewController而不是答案

GameViewController.swift

class GameViewController: UIViewController {
    var gameplay = QuestionsController(colors: colors)

    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.addSubview(gameplay.answersController.answers[0].button)
    }

    func didPressAnswerButton(sender: UIButton!) {
        sender.setTitle("Im from GameViewController class", forState: .Normal)
    }
}

QuestionsController.swift

class QuestionsController {
    var question: Question
    var answersController: AnswersController
}

AnswersController.swift

class AnswersController {
    var answers = [Answer]()

    func prepareAnswers() {
        let answer = Answer()
        answers.append(answer)
    }
}

应答

class Answer{
    let button: UIButton

    func prepareButton() {
        let answerButton = AnswerButton(type: .System)
        answerButton.addTarget(self, action: "didPressAnswerButton:", forControlEvents: .TouchUpInside)
        button = answerButton
    }

    func didPressAnswerButton(sender: UIButton!) {
        sender.setTitle("Im from Answer class", forState: .Normal)
    }
}

推荐答案

addTarget:action:forControlEvents:告诉控件(在本例中为answerButton)当用户点击按钮时要调用什么方法，以及在哪个对象上调用它。更详细地查看您的代码：

 answerButton.addTarget(self, action: "didPressAnswerButton:", forControlEvents: .TouchUpInside)