Question

我有像这样的代码

  func showSearchBar(searchBar: UISearchBar, navigationItem: UINavigationItem) {
    searchBar.alpha = 0
    navigationItem.titleView = searchBar
    searchBar.showsCancelButton = true
    navigationItem.setRightBarButtonItem(nil, animated: true)

    for subView in searchBar.subviews  {
        for subsubView in subView.subviews  {
            if let textField = subsubView as? UITextField {
                textField.attributedPlaceholder =  NSAttributedString(string:NSLocalizedString("Search", comment:""),
                    attributes:[NSForegroundColorAttributeName: UIColor(red: 25/255, green: 128/255, blue: 214/255, alpha: 1)])
                textField.font = UIFont(name:"AvenirNext-Medium", size: 15)
                textField.textColor = UIColor(red: 65/255, green: 65/255, blue: 65/255, alpha: 1)
            }
        }
    }

    UIView.animateWithDuration(0.5, animations: {
        searchBar.alpha = 1
        }, completion: { finished in
            searchBar.becomeFirstResponder()
    })

}

    func hideSearchBar(searchBar: UISearchBar, navigationItem: UINavigationItem, navigationController: UINavigationController, leftButton: UIBarButtonItem) {

    let button = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Search, target: self, action: "showSearchBar:")
    searchBar.alpha = 0
    navigationController.navigationBar.topItem?.rightBarButtonItem = button
    navigationItem.setLeftBarButtonItem(leftButton, animated: true)
    searchBar.clipsToBounds = true
    UIView.animateWithDuration(0.3, animations: {
        navigationController.navigationBar.alpha = 1
        }, completion: { finished in

    })
}

我在调用func hideSearchBar后出错了我不知道，但我认为错误，因为我在hideSearchBar中调用showSearchBar但在showSearchBar上有2个参数，但我没有发送它...我怎么能在动作上发送2个参数

我试过

showSearchBar:
showSearchBar::

但它仍然是错误，我该怎么办？或者我的代码有其他错误？

Answer 1

要使名称正确，您需要将Swift方法声明转换为该方法的Objective-C名称。这种翻译很简单，并且遵循完全机械化的规则，但是您将输入名称作为文字字符串，并且输入错误很容易，所以要小心：

名称以方法名称中左括号前面的所有内容开头。
如果方法不带参数，请停止。这就是名字的结尾。
如果方法采用任何参数，请添加冒号。
如果方法需要多个参数，请添加除第一个参数外的所有参数的外部名称，并在每个外部参数名称后添加冒号。

注意这意味着如果方法接受任何参数，其Objective-C名称将以冒号结束。大写计数，名称不应包含空格或除冒号外的其他标点符号。

为了说明，这里有三个Swift方法声明，其Objective-C名称在注释中以字符串形式给出：

func sayHello() -> String // "sayHello"

func say(s:String) // "say:"

func say(s:String, times n:Int) // "say:times:"

即使您的选择器名称与声明的方法正确对应，也可能会崩溃。例如，这是一个小测试class创建NSTimer并告诉它每秒调用一次特定方法：

class MyClass {
    var timer : NSTimer? = nil
    func startTimer() {
        self.timer = NSTimer.scheduledTimerWithTimeInterval(1,
            target: self, selector: "timerFired:",
            userInfo: nil, repeats: true)
    }
    func timerFired(t:NSTimer) {
        println("timer fired")
    }
}

class结构上没有错;它编译，并可以在应用程序运行时实例化。但是当我们打电话给startTimer时，我们会崩溃。问题不在于timerFired不存在，或者"timerFired:"不是它的名字;问题是Cocoa找不到timerFired。反过来，这是因为我们的类MyClass是一个纯粹的Swift类;因此，它缺乏允许Cocoa查看和调用timerFired的Objective-C内省和消息发送机制。以下任何一种解决方案都可以解决问题：

将MyClass声明为NSObject。
使用MyClass属性声明@objc。
使用timerFired属性声明@obc。
使用timerFired关键字声明dynamic。（但这可能有点过分;你应该保留在需要它的情况下使用dynamic，即Objective-C需要能够改变类成员的实现。）

这是Documentation。

在你的情况下这样做：

"showSearchBar:navigationItem:"

<强>更新

从项目中删除General.swift，并使用以下代码替换Home.swift中的代码：

@IBAction func searchBarAction(sender: AnyObject) {

    showSearchBar(self.searchBar, navItem: self.navigationItem)

}

func showSearchBar(searchBar: UISearchBar, navItem navigationItem: UINavigationItem) {
    searchBar.alpha = 0
    navigationItem.titleView = searchBar
    searchBar.showsCancelButton = true
    navigationItem.setRightBarButtonItem(nil, animated: true)

    for subView in searchBar.subviews  {
        for subsubView in subView.subviews  {
            if let textField = subsubView as? UITextField {
                textField.attributedPlaceholder =  NSAttributedString(string:NSLocalizedString("Search", comment:""),
                    attributes:[NSForegroundColorAttributeName: UIColor(red: 25/255, green: 128/255, blue: 214/255, alpha: 1)])
                textField.font = UIFont(name:"AvenirNext-Medium", size: 15)
                textField.textColor = UIColor(red: 65/255, green: 65/255, blue: 65/255, alpha: 1)
            }
        }
    }

    UIView.animateWithDuration(0.5, animations: {
        searchBar.alpha = 1
        }, completion: { finished in
            searchBar.becomeFirstResponder()

    })
}

//MARK: UISearchBarDelegate
func searchBarCancelButtonClicked(searchBar: UISearchBar) {
    hideSearchBar(self.searchBar, navigationItem: self.navigationItem, navigationController: self.navigationController!, leftButton: btnMenu)
}

func hideSearchBar(searchBar: UISearchBar, navigationItem: UINavigationItem, navigationController: UINavigationController, leftButton: UIBarButtonItem) {

    let button = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Search, target: self, action: "searchBarAction:")  //add your button action here.

    searchBar.alpha = 0
    navigationItem.rightBarButtonItem = button
    navigationItem.setLeftBarButtonItem(leftButton, animated: true)
    searchBar.clipsToBounds = true
    UIView.animateWithDuration(0.3, animations: {
        navigationController.navigationBar.alpha = 1
        }, completion: { finished in

    })
}

动作参数

1 个答案: