我有下面列出的2个控制器。我正在使用委托来尝试创建一个progressWindow，它将运行代码并很好地打印它，但是代码是任意的。
闭包是由符合协议的类（在我的例子中是SyncViewController）定义的，但是我想将progressWindowViewController的UI从SyncViewControllers codeToRun{}闭包中更改。我该怎么做？
同步视图控制器.swift
import UIKit
class SyncViewController: UIViewController, progressWindowDelegate {
var codeToRun = {
//(self as! ProgressWindowViewController).theTextView.text = "changed the text"
print("code to run")
}
var codeToCancel = {print("code to cancel")}
var titleToGive = "Starting Sync..."
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
@IBAction func yesSyncButtonAction(sender: UIButton) {
//Segue to the ProgressWindowViewController...
}
@IBAction func noSyncActionButton(sender: UIButton) {
tabBarController?.selectedIndex = 1 //assume back to inventory section
}
// MARK: - Navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if(segue.identifier == "SyncToProgressSegue"){
let progressWindow = segue.destinationViewController as! ProgressWindowViewController
progressWindow.controllerDelegate = self //sets the delegate so we have reference to this window still.
}
}
}
进度窗口视图控制器.swift
import UIKit
protocol progressWindowDelegate{
var titleToGive : String {get}
var codeToRun : ()->() {get}
var codeToCancel : ()->() {get}
}
class ProgressWindowViewController: UIViewController {
@IBOutlet weak var theTextView: UITextView!
@IBOutlet weak var theProgressBar: UIProgressView!
@IBOutlet weak var navItemLabel: UINavigationItem!
//Sets delegate
var controllerDelegate:progressWindowDelegate!
override func viewDidLoad() {
super.viewDidLoad()
navItemLabel.title! = controllerDelegate.titleToGive
dispatch_async(dispatch_get_main_queue(),{
self.controllerDelegate.codeToRun() //Will run code accordingly.
})
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
@IBAction func cancelNavItemButtonAction(sender: UIBarButtonItem) {
dispatch_async(dispatch_get_main_queue(),{
self.controllerDelegate.codeToCancel()
})
}
/*
// 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.
}
*/
}
一个可能使用his的例子是下载数千个带有图像的库存记录，当它将库存详细信息捕获到progressWindow中时，这些记录将打印出来。
但是这个progressWindow也可以用于其他需要将特定内容打印到progressWindow文本区域的大型/小型任务（比如登录，因此来自不同的视图控制器，而不是我的示例中的sync）。我们的想法是让它成为一个动态的类。
最佳答案
不是创建变量，而是使用函数/方法？
override func viewDidLoad() {
super.viewDidLoad()
dispatch_async(dispatch_get_main_queue(),{
self.controllerDelegate?.codeToRun(self)
})
}
.
protocol progressWindowDelegate : class {
var titleToGive : String {get}
func codeToRun(progressWindowViewController:ProgressWindowViewController)
var codeToCancel : ()->() {get}
}
class SyncViewController: UIViewController, progressWindowDelegate {
func codeToRun(progressWindowViewController:ProgressWindowViewController) {
print("code to run")
}
还可以使委托变弱和可选：
delegate weak var controllerDelegate:progressWindowDelegate? = nil
关于ios - swift如何关闭类的引用属性？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/36495208/