Ios 尝试从其他视图控制器调用函数时出错
我有两个视图控制器,希望从第二个视图控制器中的第一个视图控制器调用一个函数 这项工作:Ios 尝试从其他视图控制器调用函数时出错,ios,swift,Ios,Swift,我有两个视图控制器,希望从第二个视图控制器中的第一个视图控制器调用一个函数 这项工作: class ViewControllerOne: UIViewController { func doSomething() { print("Did something") } } class ViewControllerTwo: UIViewController { override func viewDidLoad() { super.vi
class ViewControllerOne: UIViewController {
func doSomething() {
print("Did something")
}
}
class ViewControllerTwo: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let vcOne: ViewControllerOne = ViewControllerOne()
vcOne.doSomething()
}
}
但是当我将self.ScrollView.setContentOffset(…)
(ScrollView
是ViewControllerOne
中的IBOutlet
)放在doSomething()
函数中时,我在展开可选值时意外地发现为零。一旦从ViewControllerTwo
调用该函数。如果有人能解释一下我做错了什么,也许还能解释一下如何改正,那就太好了
导致错误的实际代码:
class PageContainerViewController: UIViewController {
@IBOutlet weak var ScrollView: UIScrollView!
...
func setOffset() {
self.ScrollView.setContentOffset(CGPoint(x: 0, y: 0), animated: true)
}
...
}
class ContactsTableViewController: UITableViewController {
...
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
let selected = __contacts[indexPath.row]
if !__chats.contains(selected) {
__chats.append(selected)
let pageContainer: PageContainerViewController = PageContainerViewController()
pageContainer.setOffset()
}
activeChat = selected
print(__chats)
}
...
}
好的,这就是你要做的,根据这个例子,这是方法: 第一个
视图控制器的代码
:
import UIKit
public class ViewController: UIViewController {
public override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
public override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
public func DoSomething(parameter: String) ->String{
return parameter
}
}
import UIKit
class ViewController2: UIViewController {
@IBOutlet var labelParameter: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
let controller: ViewController = ViewController()
labelParameter.text = controller.DoSomething("Test")
// Do any additional setup after loading the view.
}
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 prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
// Get the new view controller using segue.destinationViewController.
// Pass the selected object to the new view controller.
}
*/
}
这是第二个视图控制器的代码:
import UIKit
public class ViewController: UIViewController {
public override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
public override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
public func DoSomething(parameter: String) ->String{
return parameter
}
}
import UIKit
class ViewController2: UIViewController {
@IBOutlet var labelParameter: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
let controller: ViewController = ViewController()
labelParameter.text = controller.DoSomething("Test")
// Do any additional setup after loading the view.
}
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 prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
// Get the new view controller using segue.destinationViewController.
// Pass the selected object to the new view controller.
}
*/
}
故事板我认为是无关的,但让我知道如果你需要它;从技术上讲,我有一个带按钮的第一个视图控制器,该按钮有一个序列,第二个视图控制器从第一个视图控制器调用DoSomething
方法
我希望这就是您要寻找的想法。您好,您是否在func声明中添加了公共保留字?只是尝试了一下,没有帮助。查看控制器1
是否以前出现过,然后它显示了查看控制器2
?我使用的是objective-C而不是swift,但在本例中我使用的是委托。通过委托,您可以从另一个视图控制器在另一个视图控制器中执行代码。我认为玩具可以为我们的孩子树立榜样swift@t4nhptViewControllerOne
有一个滚动视图,ViewControllerTwo
是该滚动视图的子视图。问题不是从另一个视图控制器调用函数,而是当我从另一个函数以任何方式访问ScrollView的setContentOffset时,我得到了“意外发现零”。感谢您的回答,但调用该函数不是问题,仅访问正在调用的函数中的scrollView就给了我一个错误。编辑我的帖子以包含导致错误的代码。