在许多VC中使用活动指示器而不重复代码swift [英] use activity indicator in many VC without duplicating code swift

问题描述

我在swift IOS中有两个 ViewControllers （A和B）。 A和B都从互联网（单独）加载数据。我想在加载时显示 activityIndi​​cator 。我知道我可以通过在每个VC中声明一次来做坏事，如下所示

I have two ViewControllers (A and B) in swift IOS. Both A and B loads data from internet (separately). I want to display activityIndicator while loading. I know I can do it the bad way by declaring it once in each VC as follows

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()
}

并对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，我想让代码更清晰。怎么可能呢？我这些天试图使代码更清洁。

and do the exact same for ViewController B and call the activityIndicatorBegin and activityIndicatorEnd functions that is declared in B view controller. However, I want to make the code cleaner. How could it be done? I am trying to make code cleaner these days.

谢谢，

- 更新 -

我会像以下代码一样成像。但它并不是因为我无法在扩展中声明变量

I would imageing something like the following code would work. But it doesnt because I cant declare variables in extensions

    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()
    }
}

推荐答案

创建一个 BaseViewController 并添加这两个方法并声明 activityIndi​​cator BaseViewController 中的对象。现在将 BaseViewController 作为所有 ViewController 的父类。之后，如果你想添加指标，只需像这样调用

Create one BaseViewController and add these two method and declare activityIndicator object inside that BaseViewController. Now make BaseViewController as parent class of all your ViewController. After that if you want to add the indicator simply call like this

1）创建BaseViewController

1) Create 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）现在将此 BaseViewController 指定为所有 viewController 的父级，如下所示

2) Now assign this BaseViewController as parent of your all viewController like this

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.
    } 
}

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