我有两个视图,我想将数据从一个视图传递到下一个视图。第一个视图是我有数据,我想传递给下一个视图让我们称之为SourceViewController
。然而SourceViewController
嵌入在NavigationViewController
中,secondViewController让我们称之为DestinationViewController
是TabViewController
中的第一个View。
我试图使用this question的答案,它无法超越导航视图,它只是跳过了整个逻辑。
这是我的代码:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if (segue.identifier == "loginSuccessSugue") {
if let tab = self.presentingViewController as? UITabBarController,
let nav = tab.viewControllers?[0] as? UINavigationController,
let destinationVC = nav.viewControllers.first as? HomeViewController {
destinationVC.currentBalance = serviceBalance
}
}
}
这是HomeViewController
:
class HomeViewController: UIViewController , UITableViewDelegate,UITableViewDataSource, UICircularProgressRingDelegate{
var currentBalance = 0.0
override func viewDidLoad() {
super.viewDidLoad()
circularBalance.maxValue = CGFloat(currentBalance)
print(currentBalance)
}
override func viewDidAppear(_ animated: Bool) {
print(currentBalance)
circularBalance.setProgress(value: CGFloat(currentBalance), animationDuration: 3)
}
}
这就是故事板的样子:
这是我的视图控制器,您可以在其中检查我是否向tabbar第一个viewcontroller发送5:
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
self.performSegue(withIdentifier: "segueIdentifier", sender: self)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let barViewControllers = segue.destination as! UITabBarController
let destinationNv = barViewControllers.viewControllers?[0] as! UINavigationController
let destinationViewController = destinationNv.viewControllers[0] as! FirstViewController
destinationViewController.currentBalance = 5
}
}
现在您可以检查我的第一个视图控制器,您可以在哪里检查我们获得的值。
class FirstViewController: UIViewController {
var currentBalance = 0
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
print(currentBalance)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
来自Apple的UIViewController
文档:
是presentViewController:UIViewController?
提供此视图控制器的视图控制器。
哪个对你有用,**如果**你试图回到你的导航层次,就像SO post you referenced中的那个人一样。
你正在尝试将你的SourceViewController
的VC提供的SOURCEVIEWCONTROLLER作为UITabBarController
,它失败了,这就是为什么你从来没有在嵌套的if let
中打破断点。
如果我们在docs中查看下一个变量,我们可以看到一些东西将我们带到我们呈现的UIViewController
:
presentViewController:UIViewController?
视图控制器,由此视图控制器或视图控制器层次结构中的一个祖先呈现。
所以现在回顾一下解决困境所需的代码。我会给你你发布的相同代码,但在评论中修复我的动词时态:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if (segue.identifier == "loginSuccessSugue") {
//ing -> ed
if let tab = self.presentingViewController as? UITabBarController,
let nav = tab.viewControllers?[0] as? UINavigationController,
let destinationVC = nav.viewControllers.first as? HomeViewController {
destinationVC.currentBalance = serviceBalance
}
}
当英语语言哄骗你时,不是很沮丧吗?
编辑:
由于您在prepareForSegue:
中传递数据,您实际上想要从UITabBarController
获取segue.destination
。而且由于UITabBarController
的ViewControllers
财产在为segue做准备时将为零或空。这是传递数据的糟糕方法。
您可能需要创建UITabBarController
的自定义子类,将其传递给变量,然后将该数据传递到viewControllers
中的viewDidLoad
。
class MyTabBarController: UITabBarController {
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
var serviceBalance : Double?
override func viewDidLoad() {
super.viewDidLoad()
//Make sure vc is not null or empty before continuing.
guard let vcs = viewControllers, !vcs.isEmpty else {
return
}
if let navVC = vcs[0] as? UINavigationController, let destinationVC = navVC.viewControllers[0] as? UIViewController {
destinationVC.serviceBalance = destinationVC
}
}
}
更新了prepareForSegue:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let tabBarVC = segue.destination as? MyTabBarController {
tabBarVC.serviceBalance = serviceBalance
}
}
别忘了将故事板的身份检查员中的UITabBarController
班改为MyTabBarController
您需要更改if()
条件代码。
使用下面的代码将获得你的HomeViewController
在segue的目的地。
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if (segue.identifier == "loginSuccessSugue") {
if let destinationVC = segue.destination as? HomeViewController {
destinationVC.currentBalance = serviceBalance
}
}
}
和segue.destination
一样,你会得到你的HomeViewController
,所以不需要从Tab + Navigation堆栈中获取它。
希望这会有所帮助!
编辑:
let destinationVC = segue.destination as? HomeViewController
Print(destinationVC)