在Swift中创建从UISplitViewDetail到master的委派时出错

Question

SWIFT /iOS8.2我试图将我的代码设置为代理目标，这样我就可以获取数据--但我似乎设置错了："EXC_BAD_ACCESS ( CalculatorViewController：2)“

(在GraphView.swift中)

protocol CalculatorViewDataSource: class {
    func calculateYForXEquals(sender: CalculatorViewController, currentX: CGFloat) ->CGFloat?
}

class GraphView: UIView {
    weak var calculatorViewDataSource: CalculatorViewDataSource?
    //...
}

(在GraphViewController.swift中)

class GraphViewController: UIViewController {
    @IBOutlet weak var graphView: GraphView! {
        didSet{
            graphView.calculatorViewDataSource = self.view.superview?.superview as CalculatorViewController
        }
    }
// ...
}

(在CalculatorViewController.swift中)

class CalculatorViewController: UIViewController, CalculatorViewDataSource{
    // ...
}

func calculateYForXEquals(sender: CalculatorViewController, currentX: CGFloat) ->CGFloat? {
    return nil
}

问题：

当我尝试在GraphViewController中设置委托时，我得到了一个"EXC_BAD_ACCESS (代码:2)“错误的崩溃...知道为什么吗？

我不知道如何从CalculatorViewController级别到达类。下面是故事板：

-> SplitViewController - NavigationController - (Master) CalculatorViewController
         I
     NavigationController - (Detail) GraphViewController

Answer 1

试着这样做：

    var graphViewController: GraphViewController?

    private func setupSplitViewController() {
        let masterNavigationController: AnyObject? = splitViewController?.viewControllers.first
        graphViewController = masterNavigationController!.topViewController as? GraphViewController
        graphViewController!.graphView.calculatorViewDataSource = self
    }