Getting the number of fingers touching a UIView

Question

I want to change the color of a UIView based on the number of touches currently on it. I have managed to create this with a single touch:

class colorChangerViewClass: UIView {

    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        setColor(color: .blue)
        print("touchesBegan")
    }

    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        setColor(color: .green)
        print("touchesEnded")
    }


    func setColor(color: UIColor) {
    self.backgroundColor = color
    }
}

But I am struggling with implementing multitouch. I feel like I'm not understanding something here.

Does UIView have a property to check how many fingers are currently touching it?

I could check that each time a new touchesBegan or touchesEnded occurs.

abdullahselek · Accepted Answer · 2017-04-18T14:21:11.183

7

First enable multi touch on your subclass

self.isMultipleTouchEnabled = true

Then inside your touch event functions you can get all touches with event from your UIView class.

let touchCount = event?.touches(for: self)?.count

edited Apr 18 '17 at 14:21

answered Apr 18 '17 at 14:14

abdullahselek

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`event?.touches(for: self)?.count` may not always working, `event?.allTouches?.count` can also be helpful in `touchesBegan` method. – kevinzhow Jan 08 '21 at 06:20

score 1 · Answer 2 · answered Apr 18 '17 at 14:19

Make sure the UIView has isMultipleTouchEnabled = true, the default is false.

Then change the touchesBegan method

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        setColor(color: .blue)
        let touchCount = event?.touches(for: self)?.count
    }

Getting the number of fingers touching a UIView

2 Answers2