委托-从不同的视图更改变量 [英] Delegation - Change variables from different viewsControllers

问题描述

我在container2View上有一个UIImageView（img）作为IBOutlet。如何更改img.image并从其他容器（containerView）刷新视图？

I have an UIImageView (img) on the container2View as an IBOutlet. How can I change the img.image and refresh the view from other container (containerView)?

我们必须使用委托

mainController

class mainController: UIViewController, containerDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

        switch segue.identifier! {

            case "container":

            var view = segue.destinationViewController as containerController
            view.delegate = self

            break

            default: break
        }
    }

    func change(name: String) {

        println(name)    //prints the name
        container2Controller().img.image = UIImage(named: "name")   //not seems to work
    }
}

containerController

protocol containerDelegate {

    func change(name: String)
}

class containerController: UIViewController {

    var delegate: containerDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    @IBAction func click() {

        delegate?.change("hi")    
    }
}

container2Controller

class container2Controller: UIViewController, containerDelegate {

    @IBOutlet var img: UIImageView!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    func change(name: String){

        self.img.image = UIImage(named: name)
    }
}

推荐答案

您可以使用 < a href = https://developer.apple.com/library/ios/documentation/General/Conceptual/DevPedia-CocoaCore/Delegation.html rel = nofollow>授权 。假设 container2 有一个按钮，当按下该按钮时，应启动对 container4 的更新。

You could handle this by using delegation. Let's say container2 has a button that when pressed should initiate an update to container4.

在 Container2 中，声明一个委托协议，例如：

In Container2, declare a delegate protocol like:

@protocol Container2Delegate
- (void) actionDidOccurInContainer2: (Container2) container2;
@end

并向 Container2 类：

@property (weak, nonantomic) id<Container2Delegate> delegate;

然后在 super Container中实现委托方法，并设置 Container2 委托为 super Container（如果使用情节提要，则在 prepareForSegue 中）。

Then implement the delegate method in the superContainer, and set Container2s delegate to be the superContainer (in prepareForSegue if you're using storyboards).

在方法实现中，您可以更新 Container4 ：

In the method implementation, you can update Container4:

- (void) actionDidOccurInContainer2: (Container2) container2 {
     container4.imageView.image = <your image>
}

在 container2 中会有类似的内容：

- (IBAction)doSomething: (id) sender
{
    [self.delegate actionDidOccurInContainer2: self];
}

这篇关于委托-从不同的视图更改变量的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！