Question

我尝试用swift手指演示移动按钮。

所以我写了一个像底部的类实现UIButton。问题是移动时按钮会跳过一小段距离。

我想知道为什么？

谢谢！

import UIKit

class MoveAbleButton: UIButton {
    override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {}
    override func touchesCancelled(touches: Set<NSObject>!, withEvent event: UIEvent!) {}
    override func touchesEnded(touches: Set<NSObject>, withEvent event: UIEvent) {}

    override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {
        let touch = touches.first

        if let touchTemp = touch {
            let t = touchTemp as! UITouch

            let point = t.locationInView(self)

            let x = self.frame.origin.x + point.x
            let y = self.frame.origin.y + point.y
            let w = self.frame.width
            let h = self.frame.height

            self.frame = CGRectMake(x, y, w, h)

//            let x = self.center.x + point.x
//            let y = self.center.y + point.y
//            
//            let newCenter = CGPoint(x: x, y: y)
//            
//            self.center = newCenter

            println("touchesMoved (\(point.x),\(point.y))")
        }
    }
}

Answer 1

您需要在移动按钮之前计算按钮的左上角和触摸点之间的距离。这是我的代码：

class MoveAbleButton: UIButton {
var distantX:CGFloat!
var distantY:CGFloat!
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
    distantX = ((touches.first as! UITouch).locationInView(self)).x
    distantY = ((touches.first as! UITouch).locationInView(self)).y
}
override func touchesCancelled(touches: Set<NSObject>!, withEvent event: UIEvent!) {}
override func touchesEnded(touches: Set<NSObject>, withEvent event: UIEvent) {}

override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {
    let touch = touches.first

    if let touchTemp = touch {
        let t = touchTemp as! UITouch

        let pointInSuperView = t.locationInView(self.superview)

        let x = pointInSuperView.x - distantX
        let y = pointInSuperView.y - distantY
        let w = self.frame.width
        let h = self.frame.height

        self.frame = CGRectMake(x, y, w, h)

        //            let x = self.center.x + point.x
        //            let y = self.center.y + point.y
        //
        //            let newCenter = CGPoint(x: x, y: y)
        //
        //            self.center = newCenter

        //println("touchesMoved (\(point.x),\(point.y))")
    }
}

}

当手指快速移动时，uibutton跳过一段距离

1 个答案: