everyone knows that when you drag outside a button it don't cancel the highlight state right away by UIButton's default. UIControlEventTouchDragExit triggers when 70 pixels away. I want that distance to be 0. So after searching the solution of it, I tried to create a subclass like this:
import UIKit
class UINewButton: UIButton {
override func continueTrackingWithTouch(touch: UITouch, withEvent event: UIEvent?) -> Bool {
print("here")
let touchOutside = !CGRectContainsPoint(self.bounds, touch.locationInView(self))
if touchOutside {
let previousTochInside = CGRectContainsPoint(self.bounds, touch.previousLocationInView(self))
if previousTochInside {
print("Sending UIControlEventTouchDragExit")
self.sendActionsForControlEvents(.TouchDragExit)
self.highlighted = false
self.selected = false
}else{
print("Sending UIControlEventTouchDragOutside")
self.sendActionsForControlEvents(.TouchDragOutside)
}
}else{
let previousTouchOutside = !CGRectContainsPoint(self.bounds, touch.previousLocationInView(self))
if previousTouchOutside{
print("Sending UIControlEventTouchDragEnter")
self.sendActionsForControlEvents(.TouchDragEnter)
}else{
print("Sending UIControlEventTouchDragInside")
self.sendActionsForControlEvents(.TouchUpInside)
}
}
return super.continueTrackingWithTouch(touch, withEvent: event)
}
}
and create a button like this in a UIViewController
@IBOutlet var confirmButton: UINewButton!
I assumed when a UIButton being touched and dragged. It would call the function in this sequence:
beginTrackingWithTouch(when touched) -> continueTrackingWithTouch(when dragged) -> endTrackingWithTouch(when left)
But here is the weird part. Even though I override the function continueTrackingWithTouch, it still not been called. Cause the console window didn't show "here" where I put there in it. And the result remain the default distance 70. how come is that?
I tried to call the three functions mentioned above and return true if it needs one. What did I missed?
After reading this article: UIControlEventTouchDragExit triggers when 100 pixels away from UIButton Still not helping :( (plus it written in objective-C...)
Isn't the distance of 70px a property of the function so I can just changed?(How can I see the original function by the way? There is no detail in Apple Developer Documentation...) Should I use button.addtarget in the UIViewController? But it seems like another way to do it.
Here is another question: If I want to cancel the highlight state when dragged outside the button, is this right?
self.highlighted = false
self.selected = false
I don't know which one is the right one so I used it all.
please help! Just a newbie in swift but I have been stuck in this problem for 3 days. QQ
