Swift UIPanGestureRecognizer right to left only - ios

Question

I'm building a slide out menu using a tutorial from Ray Wenderlich and can't figure out how to disable left to right panning but keep right to left? I remove addLeftPanelViewController() but it still shows the pan, just not working correctly. I don't want anything to move, or unhide on the left to right.
Thanks for any help.
override func viewDidLoad() {
let panGestureRecognizer = UIPanGestureRecognizer(target: self, action: "handlePanGesture:")
centerNavigationController.view.addGestureRecognizer(panGestureRecognizer)
}
let gestureIsDraggingFromLeftToRight = (recognizer.velocityInView(view).x > 0)
 
switch(recognizer.state) {
case .Began:
if (currentState == .BothCollapsed) {
if (gestureIsDraggingFromLeftToRight) {
addLeftPanelViewController()
} else {
addRightPanelViewController()
}
 
showShadowForCenterViewController(true)
}
case .Changed:
recognizer.view!.center.x = recognizer.view!.center.x + recognizer.translationInView(view).x
recognizer.setTranslation(CGPointZero, inView: view)
case .Ended:
if (leftViewController != nil) {
// animate the side panel open or closed based on whether the view has moved more or less than halfway
let hasMovedGreaterThanHalfway = recognizer.view!.center.x > view.bounds.size.width
animateLeftPanel(shouldExpand: hasMovedGreaterThanHalfway)
} else if (rightViewController != nil) {
let hasMovedGreaterThanHalfway = recognizer.view!.center.x < 0
animateRightPanel(shouldExpand: hasMovedGreaterThanHalfway)
}
default:
break
}

Answer 1

try this
add Expending on the SlideOutState enum
enum SlideOutState {
case BothCollapsed
case SettingPanelExpanded
case Expanding
}
then
switch(recognizer.state) {
case .Began:
if (currentState == .BothCollapsed) {
if (gestureIsDraggingFromLeftToRight) {
addSettingPanelViewController()
showShadowForCenterViewController(true)
currentState = .Expanding
}
}
if (currentState == .SettingPanelExpanded) {
if (gestureIsDraggingFromLeftToRight==false) {
currentState = .Expanding
}
}
case .Changed:
if (currentState == .Expanding){
println(recognizer.velocityInView(view).x)
recognizer.view!.center.x = recognizer.view!.center.x + recognizer.translationInView(view).x
recognizer.setTranslation(CGPointZero, inView: view)
}
case .Ended:
if (settingViewController != nil) {
// animate the side panel open or closed based on whether the view has moved more or less than halfway
let hasMovedGreaterThanHalfway = recognizer.view!.center.x > view.bounds.size.width
animateSettingPanel(shouldExpand: hasMovedGreaterThanHalfway)
}
default:
break
}

Answer 2

Wrap your switch statement in an if condition:
if currentState == .LeftPanelExpanded || gestureIsDraggingFromLeftToRight {
//your existing switch statement
}