Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
818 views
in Technique[技术] by (71.8m points)

ios - Get coordinates of multiple touches in Swift

So I've been messing around trying to get the coordinates of touches on the screen. So far I can get the coordinates of one touch with this:

override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
    let touch = touches.anyObject()! as UITouch
    let location = touch.locationInView(self.view)
    println(location)
}

But when touching with two fingers I only get the coordinates of the first touch. Multi-touch works (I tested with this little tutorial: http://www.techotopia.com/index.php/An_Example_Swift_iOS_8_Touch,_Multitouch_and_Tap_Application). So my question is, how do I get the coordinates of the second (and third, fourth...) touch?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Answer

0 votes
by (71.8m points)

** Updated to Swift 4 and Xcode 9 (8 Oct 2017) **

First of all, remember to enable multi-touch events by setting

self.view.isMultipleTouchEnabled = true

in your UIViewController's code, or using the appropriate storyboard option in Xcode:

xcode screenshot

Otherwise you'll always get a single touch in touchesBegan (see documentation here).

Then, inside touchesBegan, iterate over the set of touches to get their coordinates:

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    for touch in touches {
        let location = touch.location(in: self.view)
        print(location)
    }
}

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...