swift - 我的 scrollViewDidScroll 函数没有收到调用

Question

我正在尝试检查用户是否在我的应用上上下滚动，但它没有调用我的 scrollViewDidScroll 方法

当我在应用程序上上下滚动时，为什么它不打印 received scroll 有什么想法吗？

import UIKit

class CreateAccount: UIViewController, UITextFieldDelegate, UIScrollViewDelegate {

    @IBOutlet weak var scrollViewer: UIScrollView!
    @IBOutlet weak var usernameTextField: UITextField!
    @IBOutlet weak var emailTextField: UITextField!
    @IBOutlet weak var passwordTextField: UITextField!
    @IBOutlet weak var reenterPasswordTextField: UITextField!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
    }

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

    func scrollViewDidScroll(scrollView: UIScrollView) {
        print("received scroll")
    }

}

Answer 1

添加 ScrollView 委托(delegate)。每当你实现一个委托(delegate)方法时，你需要告诉它使用哪个 Controller ，通常是 self。它让我抓狂了几次。

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.   
    scrollViewer.delegate = self
}