iOS 快速指针

Question

CGPoint startPoint1;
CGPoint startPoint2;
CGPoint startPoint3;
CGPoint startPoint4;

- (void)Method {
    CGPoint* startPoint = NULL;

    if (panGesture.view == ...) {
       startPoint = &startPoint1;
    } else if (panGesture.view == ...) {
       startPoint = &startPoint2;
    }

    if (panGesture.state == UIGestureRecognizerStateBegan) {
       *startPoint = [panGesture locationInView:...]
    } else if (panGesture.state == UIGestureRecognizerStateChanged) {
       CGPoint endPoint = [panGesture locationInView:...];
       *startPoint = endPoint;
    }
}

CGPoint* startPoint = NULL;
startPoint = &startPoint1;
*startPoint = endPoint;

这三行代码在Swift 3.0中是如何表达的或者我如何将上面的代码写入到swift中

Answer 1

在 swift 中，我会使用枚举和数组。我稍微简化了代码，但我想你会明白的:

var points = [CGPoint(), CGPoint()]
enum indexEnum:Int {
    case startPoint = 0
    case endPoint   = 1
}

func method() {
    var inx:indexEnum

    if (1==1) {
        inx = .startPoint
    } else {
        inx = .endPoint
    }

    if (2==2) {
        points[inx.rawValue] = CGPoint(x:10,y:10)
    } else {
        points[inx.rawValue] = CGPoint(x:20,y:20)
    }
}