XLPagerTabStrip的ChildViewControllers动态数量

Question

我正在使用XLPagerTabStrip在Swift 4中创建一个基于类别的阅读应用程序。我了解到静态数字的ViewControllers可以很容易地使用以下函数创建。

override func viewControllers(for pagerTabStripController: PagerTabStripViewController) -> [UIViewController] { } 

然而，在我的例子中，类别的数量取决于服务器响应，服务器响应可能会根据需要而变化。我尝试通过基于从json响应解析的类别名称创建视图控制器来创建动态数量的选项卡。这是我做了一次测试的方法。

    override func viewControllers(for pagerTabStripController: PagerTabStripViewController) -> [UIViewController] {
    var childrenVC = [UIViewController]()
    for eachCategory in postCategories {
            print(eachCategory)
        let newVC = self.storyboard?.instantiateViewController(withIdentifier: "FirstTVC") as? FirstTVC
        newVC?.childName = eachCategory.name
        childrenVC.append(newVC!)
        self.reloadPagerTabStripView()
        self.reloadInputViews()
}
    return childrenVC
}

是的，它失败了。在这种情况下，如何实现动态页签数量？如果没有，我也对任何其他选择持开放态度。我已经完成了json响应的事情，但仍停留在这一步。这个SO answer和Github Issue也没有帮助。

Answer 1

我也遇到过同样的情况。如果您从服务器异步获取结果，那么您将会崩溃，因为xlpagertabstrip至少需要一个子视图控制器。我找到的解决方案是在应用程序开始时以及从服务器获取数据到reloadPagerTabStripView之后返回一个虚拟的视图控制器。

在父视图控制器中，您应该为从服务器获取的对象创建一个空数组，例如：

var menuItems = [MenuObject]()

接下来，viewControllers(用于pagerTabStripController ... )方法应如下所示：

override func viewControllers(for pagerTabStripController: PagerTabStripViewController) -> [UIViewController] {
    var children = [UIViewController]()
    if menuItems.count == 0 {
        let child = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "DummyVC") as! DummyVC
        children.append(child)
        return children
    } else {
        let menuItemsUrls = menuItems.map{$0.url}
        for menuItem in menuItems {
            let child = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "MainVC") as! TelegrafMainVC
            child.name = menuItem.name.uppercased
            child.url = menuItem.url
            children.append(child)
        }

        return children
    }
}

从服务器获取数据后，无论是使用URLSession、Alamofire还是其他任何工具，在函数或闭包中都应该放入如下内容：

self.menuItems = menuItems

 DispatchQueue.main.async {
       self.reloadPagerTabStripView()
 }

如果我需要澄清什么，请告诉我，但我相信这足以帮助你。干杯

Answer 2

步骤1:在初始视图控制器中执行此操作，

class initialViewController: UIViewController {
     override func viewWillAppear(_ animated: Bool) {
          self.loadMainView(viewControllerArray: self.setMainViewTabParameters())
     }

 func setMainViewTabParameters() -> NSMutableArray {
      let viewControllerArray = NSMutableArray()
      var tabArray = ["Tab1", "Tab2", "Tab3", "Tab4", "Tab5", "Tab6", "Tab7"]

      var tabIndex = NSInteger()
      for item in tabArray {
           let tabString = tabArray[tabIndex]
           let tabview = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "YourTabControllerIdentifier") as! YourTabController
           tabview.tabHeadingTitle = tabString as NSString
           viewControllerArray.add(tabview)
           tabIndex = tabIndex + 1
      }
      return viewControllerArray
 }

 func loadMainView(viewControllerArray : NSMutableArray) -> Void {
      let mainView = self.storyboard?.instantiateViewController(withIdentifier: "YourMainControllerIdentifier") as! YourMainController
      mainView.viewControllerList = viewControllerArray
      self.navigationController?.pushViewController(mainView, animated: false)
 }
}

第2步：

class YourMainController: ButtonBarPagerTabStripViewController {

     var viewControllerList = NSArray()
     var isReload = false

     //MARK: - PagerTabStripDataSource
     override func viewControllers(for pagerTabStripController: PagerTabStripViewController) -> [UIViewController] {
          guard isReload else {
               return viewControllerList as! [UIViewController]
          }

          var childViewControllers = viewControllerList as! [UIViewController]

          for (index, _) in childViewControllers.enumerated(){
               let nElements = childViewControllers.count - index
               let n = (Int(arc4random()) % nElements) + index
               if n != index{
                    swap(&childViewControllers[index], &childViewControllers[n])
               }
          }
          let nItems = 1 + (arc4random() % 8)
          return Array(childViewControllers.prefix(Int(nItems)))
     }

     override func reloadPagerTabStripView() {
          isReload = true
          if arc4random() % 2 == 0 {
               pagerBehaviour = .progressive(skipIntermediateViewControllers: arc4random() % 2 == 0, elasticIndicatorLimit: arc4random() % 2 == 0 )
          } else {
               pagerBehaviour = .common(skipIntermediateViewControllers: arc4random() % 2 == 0)
          }
          super.reloadPagerTabStripView()
     }
}

第3步:选项卡视图控制器：

class YourTabController: UIViewController, IndicatorInfoProvider {
     var tabHeadingTitle = NSString()

     // MARK: - Top Tab Bar Method - IndicatorInfoProvider
     func indicatorInfo(for pagerTabStripController: PagerTabStripViewController) -> IndicatorInfo {
          return IndicatorInfo(title: tabHeadingTitle as String)
     }
}

Answer 3

尝尝这个

override func viewControllers(for pagerTabStripController: PagerTabStripViewController) -> [UIViewController] {
    var childrenVC: [UIViewController] = []

    for eachCategory in postCategories {
         let newVC = UIStoryboard(name: "Main (YOUR-STORYBOARD-NAME)", bundle: nil).instantiateViewController(withIdentifier: "FirstTVC") as? FirstTVC
         newVC?.childName = eachCategory.name
         childrenVC.append(newVC!)
    }
    return childrenVC
}