快速准備segue不起作用

Question

CalViewController：

let brain =CalculatorBrain()
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    let graph = GraphController()
    graph.brain.record = brain.record
}

GraphViewController：

var brain = CalculatorBrain() {
    didSet {
        draw.variables = ["M": 1]
        let value = brain.evaluate(using: draw.variables)
        print(value)
//at that time outlet didn't set it prints the value work just fine
    }
}

@IBOutlet weak var graphView: GraphView! {
    didSet {
        draw.variables = ["M": 1]
        let value = brain.evaluate(using: draw.variables)
        print(value)
//when outlet got set it not working it print nothing
 }
}

我只是不知道為什么以及如何解決這個問題，將不勝感激

Answer 1

UIStoryboardSegue在其destination property包含要轉換到的實際視圖控制器。 無需將數據傳遞給該視圖控制器，而是將其傳遞給在prepareForSegue創建的全新視圖控制器（當您離開該函數時，該視圖控制器會立即刪除）。

您可能想要一些類似的東西：

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if let graph = segue.destination as? GraphController {
        graph.brain.record = brain.record
    }
}

我輸入的內容沒有編譯器的好處，因此您可能需要對其進行調整。