如何在Swift中制作一个使用“自我”的全局变量

Question

Hello Im currently using swift in xCode and I have a random number generator that produces a random point in the view.

        func randomInRange(lo: Int, hi : Int) -> Int {
            return lo + Int(arc4random_uniform(UInt32(hi - lo + 1)))
        }
        // x coordinate between MinX (left) and MaxX (right):
        let randomX = randomInRange(Int(CGRectGetMinX(self.frame) * 2), Int(CGRectGetMaxX(self.frame)))
        // y coordinate between MinY (top) and MidY (bottom):
        let randomY = randomInRange(Int(CGRectGetMinY(self.frame) * 2), Int(CGRectGetMaxY(self.frame)))
        let randomPoint = CGPoint(x: randomX , y: randomY)

I would like to global use this variable so i can use this random point multiple times rather then have to write out this entire code block every time. Now I know you can create a global variable by declaring it above the GameScene class or in-between the class and the viewDidLoad like such

class GameScene: SKScene , SKPhysicsContactDelegate {


func randomInRange(lo: Int, hi : Int) -> Int {
    return lo + Int(arc4random_uniform(UInt32(hi - lo + 1)))
}
// x coordinate between MinX (left) and MaxX (right):
let randomX = randomInRange(Int(CGRectGetMinX(self.frame) * 2), Int(CGRectGetMaxX(self.frame)))
// y coordinate between MinY (top) and MidY (bottom):
let randomY = randomInRange(Int(CGRectGetMinY(self.frame) * 2), Int(CGRectGetMaxY(self.frame)))
let randomPoint = CGPoint(x: randomX , y: randomY)


 override func didMoveToView(view: SKView) {
    /* Setup your scene here */

However when I put it above the same scene class I get the error message... "Use of unresolved identifier self" And when i put it between the gameScene class and viewDidLoad I get the error ... gameScene does not have a member named self . If possible is there a way to replace self with something else regarding the view , If so please answer. Thank you !

Answer 1

在GameScene类之上声明全局函数，并用UIScreen.main.bounds替换self.frame 。

Answer 2

You can use a singleton like this:

class MyGlobalCounters {
  var counter = 0
  var this = "Hello"
  var that:CGFloat = 1.23

  class var sharedInstance : MyGlobalCounters {
    return _SingletonSharedInstance
  }
}
private let _SingletonSharedInstance = MyGlobalCounters()


class A {
  let myGlobalCounters = MyGlobalCounters.sharedInstance
  func dumpAndInc() {
    println("ctr=\(myGlobalCounters.counter++)")
  }
}

class B {
  let myGlobalCounters = MyGlobalCounters.sharedInstance
  func dumpAndInc() {
    println("ctr=\(myGlobalCounters.counter++)")
  }
}
let a = A()
let b = B()
a.dumpAndInc() 
b.dumpAndInc() // in b we use the same instance for the counters
a.dumpAndInc() // as in a