Question

我有一个带有四个视图控制器的应用程序。 1,2和3之间的导航很好但是从视图控制器1你可以选择转到2或4（这是我的设置）我有一个从1到4的segue。然后我使用展开segue来取回。但是当我使用segue回到4时，它实例化了一个新的4实例。

我的问题：有没有办法访问用户上次使用的视图控制器的同一个实例。

Answer 1

就像@Paul11在评论中所说的那样，如果你想要访问同一个实例，你应该保留UIViewController你试图推送的参考

比如说

var someViewController = SomeViewController() // << this is at the class level scope

func someSampleFunc() {
    // doing this would create a new instance of the `SomeViewController` every time you push
    self.navigationController?.pushViewController(SomeViewController(), animated: true)

    // whereas if you use the variable which is at the class level scope the memory instance is kept
    self.navigationController?.pushViewController(someViewController, animated: true)
}

实例的另一个例子

class Bro {
    var name = "Some Name"

    func sayDude() {          
        // since `name` is a class level you can access him here

        let dude = "DUUUUUUUDE" // this variable's lifetime only exists inside the `sayDude` function, therefore everytime you call `sayDude()` a new instance of `dude` is created

        print(name)
        print(dude)
    }

    func doBackflip() {
         sayDude() //

         print(name + " does backflip") // since `name` is a class level you can access him here
    }
}

segue创建视图控制器swift的新实例

1 个答案: