委派 - 从不同的视图控制器更改变量

Question

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？

我们必须使用委托

主控制器

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
    }
}

容器控制器

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)
    }
}

Answer 1

您可以使用 delegation 处理此问题。假设container2 有一个按钮，当按下该按钮时应启动对container4 的更新。

在Container2 中，声明一个委托协议，如：

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

并将属性添加到Container2 类：

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

然后在 superContainer 中实现委托方法，并将 Container2s 委托设置为 superContainer（如果您使用故事板，则在 prepareForSegue )。

在方法实现中，可以更新Container4：

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

在container2 中，您将拥有类似的内容：

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