Question

从tabBarController，我将以模态方式呈现一个新的viewController。我想在其上实现一个panGestureRecognizer，以便用户可以向下拖动viewController来关闭它。但是，我在模态视图控制器中嵌入了一个scrollview，这使得它更加困难。

到目前为止，我的代码是一个非常便宜的解决方案：

override func viewDidLoad() {
        pan = UIPanGestureRecognizer(target: self, action: "handlePan:")
        self.scrollview.addGestureRecognizer(pan)
        self.view.addGestureRecognizer(scrollview.panGestureRecognizer)
} 

func handlePan(recognizer:UIPanGestureRecognizer!) {

    switch recognizer.state {
    case .Changed:
        handlePanChanged(recognizer); break
    case .Ended:
        handlePanTerminated(recognizer); break
    case .Cancelled:
        handlePanTerminated(recognizer); break
    case .Failed:
        handlePanTerminated(recognizer); break
    default: break
    }
}

func handlePanChanged(recognizer:UIPanGestureRecognizer!) {
    if let view = recognizer.view {
        var translation = recognizer.translationInView(self.view)
        println("moving")
        view.center = CGPointMake(view.center.x, view.center.y + translation.y);
        recognizer.setTranslation(CGPointZero, inView: self.view)
    }


}

func handlePanTerminated(recognizer:UIPanGestureRecognizer!) {
    if let view = recognizer.view {
        let offset = self.view.center.y - view.center.y
        let vel = recognizer.velocityInView(self.view).y

        if (fabs(offset) > kTriggerDistance) || (fabs(vel) > kTriggerVelocity) {
            let pointsToMove = self.pointsToMove(view, angle: 0, direction: vel > 0 ? .Down : .Up)
            let animationDuration = NSTimeInterval(min(0.3, pointsToMove / Float(vel)))

            UIView.animateWithDuration(animationDuration, animations: { () -> Void in
                view.center = CGPointMake(view.center.x, view.center.y + CGFloat(pointsToMove))
                }, completion: { (completed) -> Void in
                    self.dismissViewControllerAnimated(false, completion: nil)
                    view.removeFromSuperview()
            })
        }
        else {
            UIView.animateWithDuration(0.5, delay: 0.0, usingSpringWithDamping: 0.75,
                initialSpringVelocity: 2.0, options: nil, animations: { () -> Void in
                    view.center = self.view.center
                }, completion: nil);
        }
    }
}

虽然这允许我拖动scrollView，但我真的不知道如何拖动整个viewController。我是否必须在根视图控制器上将其作为子视图？

在viewController上淡化panGesture

0 个答案: