如何在不使用Segue的情况下在单独的UIViewController中选择实例变量

Question

I'm trying to select and set an instance variable that is part of another UIViewController, however, I don't know how to select another ViewController and access its contents without using a segue.

Whenever a user checks off a task, a percentage of tasks that are complete should be calculated and another view controller's instance variable should be set.

I realize I'm currently instantiating a new view controller instead of selecting the one I already have on the storyboard. I'm using a third party sidebar menu that resides behind my main view, although it really exists as a separate Scene/ViewController. It should be noted that this sidebar menu doesn't use a segue reveal itself. Is there any method to select another view controller and access it's instance variables?

@IBAction func checkOffTask(sender: UIButton) {

    // Select sidebar view controller
    let sidebarViewController = self.storyboard?.instantiateViewControllerWithIdentifier("sideBarScene") as! SideBarViewController

    // Calculate percentage of completed tasks
        // Select the count of all tasks
        let allTasksCount = Float(firstDataSource.count + secondDataSource.count)

        // Select the count of all completed tasks
        let completedTasksCount = Float(secondDataSource.count)

        // Divide the two to get a percentage
        var completedTaskPercentage = completedTasksCount / allTasksCount

        sidebarViewController.completedTaskPercentageTemporary = String(stringInterpolationSegment: completedTaskPercentage)

    println(sidebarViewController)
    println(sidebarViewController.completedTaskPercentageTemporary)
}

Answer 1

One trick could be find out current visible view controller and set properties on it. This thread may help you doing this.

Another way could be to get hold to targeted view controller's object when it is intialized by storyboard. For this you would need to rely on prepareForSegue:sender: method. Once you have saved the object you can pass it & use it to set the properties.