在许多 VC 中使用活动指示器而不快速复制代码

Posted 2023-03-16

【中文标题】在许多 VC 中使用活动指示器而不快速复制代码

【英文标题】：use activity indicator in many VC without duplicating code swift

【发布时间】：2016-07-19 11:50:44

【问题描述】：

我在 Swift ios 中有两个 ViewControllers（A 和 B）。 A 和 B 都从 Internet 加载数据（分别）。我想在加载时显示activityIndicator。我知道我可以通过在每个 VC 中按如下方式声明一次来做坏事

ViewController A

var activityIndicator: UIActivityIndicatorView = UIActivityIndicatorView()

func activityIndicatorBegin() 
    activityIndicator = UIActivityIndicatorView(frame: CGRectMake(0,0,50,50))
    activityIndicator.center = self.view.center
    activityIndicator.hidesWhenStopped = true
    activityIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.Gray
    view.addSubview(activityIndicator)
    activityIndicator.startAnimating()
    disableUserInteraction()

    greyView = UIView()
    greyView.frame = CGRectMake(0, 0, self.view.bounds.width, self.view.bounds.height)
    greyView.backgroundColor = UIColor.blackColor()
    greyView.alpha = 0.5
    self.view.addSubview(greyView)


func activityIndicatorEnd() 
    self.activityIndicator.stopAnimating()
    enableUserInteraction()
    self.greyView.removeFromSuperview()

对 ViewController B 执行完全相同的操作，并调用在 B 视图控制器中声明的 activityIndi​​catorBegin 和 activityIndi​​catorEnd 函数。但是，我想让代码更干净。怎么可能做到？这些天我正在努力使代码更干净。

谢谢，

--更新--

我想像下面的代码这样的东西会起作用。但这不是因为我不能在扩展中声明变量

    var activityIndicator: UIActivityIndicatorView = UIActivityIndicatorView()

extension UIViewController 
    func activityIndicatorBegin() 
    activityIndicator = UIActivityIndicatorView(frame: CGRectMake(0,0,50,50))
    activityIndicator.center = self.view.center
    activityIndicator.hidesWhenStopped = true
    activityIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.Gray
    view.addSubview(activityIndicator)
    activityIndicator.startAnimating()
    disableUserInteraction()

    greyView = UIView()
    greyView.frame = CGRectMake(0, 0, self.view.bounds.width, self.view.bounds.height)
    greyView.backgroundColor = UIColor.blackColor()
    greyView.alpha = 0.5
    self.view.addSubview(greyView)


func activityIndicatorEnd() 
    self.activityIndicator.stopAnimating()
    enableUserInteraction()
    self.greyView.removeFromSuperview()
    

【参考方案1】：

SWIFT 4

extension UIView

    func activityStartAnimating(activityColor: UIColor, backgroundColor: UIColor) 
        let backgroundView = UIView()
        backgroundView.frame = CGRect.init(x: 0, y: 0, width: self.bounds.width, height: self.bounds.height)
        backgroundView.backgroundColor = backgroundColor
        backgroundView.tag = 475647
        
        var activityIndicator: UIActivityIndicatorView = UIActivityIndicatorView()
        activityIndicator = UIActivityIndicatorView(frame: CGRect.init(x: 0, y: 0, width: 50, height: 50))
        activityIndicator.center = self.center
        activityIndicator.hidesWhenStopped = true
        activityIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.gray
        activityIndicator.color = activityColor
        activityIndicator.startAnimating()
        self.isUserInteractionEnabled = false
        
        backgroundView.addSubview(activityIndicator)

        self.addSubview(backgroundView)
    

    func activityStopAnimating() 
        if let background = viewWithTag(475647)
            background.removeFromSuperview()
        
        self.isUserInteractionEnabled = true
    

用法：

self.view.activityStartAnimating(activityColor: UIColor.white, backgroundColor: UIColor.black.withAlphaComponent(0.5))


self.view.activityStopAnimating()

【参考方案2】：

创建一个BaseViewController 并添加这两个方法并在BaseViewController 中声明activityIndicator 对象。现在将BaseViewController 设为所有ViewController 的父类。之后，如果您想添加指标，只需像这样调用

1) 创建 BaseViewController

class BaseViewController: UIViewController 
    var activityIndicator: UIActivityIndicatorView = UIActivityIndicatorView()

    override func viewDidLoad() 
        super.viewDidLoad()
    

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

    func activityIndicatorBegin() 
        activityIndicator = UIActivityIndicatorView(frame: CGRectMake(0,0,50,50))
        activityIndicator.center = self.view.center
        activityIndicator.hidesWhenStopped = true
        activityIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.Gray
        view.addSubview(activityIndicator)
        activityIndicator.startAnimating()
        disableUserInteraction()

        greyView = UIView()
        greyView.frame = CGRectMake(0, 0, self.view.bounds.width, self.view.bounds.height)
        greyView.backgroundColor = UIColor.blackColor()
        greyView.alpha = 0.5
        self.view.addSubview(greyView)
    

    func activityIndicatorEnd() 
        self.activityIndicator.stopAnimating()
        enableUserInteraction()
        self.greyView.removeFromSuperview()
    

2) 现在将这个BaseViewController 指定为你所有viewController 的父级，就像这样

class ViewController1: BaseViewController 

    override func viewDidLoad() 
        super.viewDidLoad()
        //Now if you want to add activityIndicator call like this
        self.activityIndicatorBegin()
        //or if you want remove activityIndicator 
        self.activityIndicatorEnd()
    

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

【讨论】：

这是否意味着我需要在情节提要中物理创建另一个（第三个）VC 并将其分配给 BaseViewController 并且它什么也不做？我对我的想法有一些更新

谢谢，它成功了。所以基本上不是做扩展：UIviewcontroller，我把它改成类并让另一个类继承它。智能

欢迎。但是extension 也很有帮助，如果你想要像UITextField、UIButton、UILabel 等带有一些自定义属性的控件，那么extension 是一个不错的选择。希望你能明白。快乐编码。

【参考方案3】：

您是否尝试使用可以在 A 类和 B 类中复制的所有代码创建一个基类？如果这些类正在做完全不同的事情，您可以为活动指示器添加扩展

【讨论】：

一个VC是tableView，另一个是collectionView。我该如何做扩展。请参阅上面的更新。谢谢

@EdwardHung 你有大量的全球活动指标示例mpclarkson.github.io/2016/01/06/…