小编Lin*_*nas的帖子

这个简单的线条动画让我有些挣扎。我想出了如何暂停它，但是我需要的是能够从调用函数resetAnimation（）的那一刻起就将动画反向还原到起点。

let pathAnimation = CABasicAnimation(keyPath: "strokeEnd")
    let pathLayer = CAShapeLayer()

     func lineAnimation() {

        let path = UIBezierPath()
        let screenWidth = self.view.bounds.width
        let screenHeight = self.view.bounds.height
        path.moveToPoint(CGPointMake(screenWidth, screenHeight / 2))
        path.addLineToPoint(CGPointMake(screenWidth - screenWidth, screenHeight / 2))

        self.pathLayer.frame = self.view.bounds
        self.pathLayer.path = path.CGPath
        self.pathLayer.strokeColor = UIColor.whiteColor().CGColor
        self.pathLayer.fillColor = nil
        self.pathLayer.lineWidth = 3.0
        self.pathLayer.lineCap = kCALineCapRound
        self.pathLayer.speed = 1

        self.view.layer.addSublayer(pathLayer)

        self.pathAnimation.duration = 5.0
        self.pathAnimation.fromValue = 0.0
        self.pathAnimation.toValue = 1.0

        pathLayer.addAnimation(pathAnimation, forKey: "animate")

    }

    func pauseAnimation() {

        let pausedTime = pathLayer.convertTime(CACurrentMediaTime(), fromLayer: nil)
        pathLayer.speed …

我想在我的应用程序上创建 Facebook 共享按钮，该按钮共享从 UIImageview 加载的图像。我不知道该怎么做.. 可以选择在 Facebook 共享窗口上添加文本，但无法添加图像。请帮忙。

import UIKit
import Social

class ViewController: UIViewController {


    @IBOutlet weak var saveButtonVar: UIButton!
    @IBOutlet weak var image: UIImageView!

    @IBAction func facebookBtn(sender: AnyObject) {
        var facebookBtn : SLComposeViewController = SLComposeViewController(forServiceType: SLServiceTypeFacebook)
            facebookBtn.setInitialText("I am sharing my motivation with you!")
            facebookBtn.addImage(UIImage(named: "motImg")) //????
        self.presentViewController(facebookBtn, animated: true, completion: nil)

    }

    @IBAction func twitterBtn(sender: AnyObject) {

    }





    @IBAction func saveButton(sender: AnyObject) {

        UIImageWriteToSavedPhotosAlbum(image.image, nil, nil, nil)

        let alertController = UIAlertController(title: "Image Saved!", message:
            "", preferredStyle: UIAlertControllerStyle.Alert)
        alertController.addAction(UIAlertAction(title: …

我是新手,对我遇到的这个问题感到沮丧.

我想要做的非常简单:在屏幕中央画一条直线并为其制作动画.听起来很简单吧？是啊..这就是我现在所拥有的.

import UIKit

class Drawings: UIView {


    override func drawRect(rect: CGRect) {

        let screensize: CGRect = UIScreen.mainScreen().bounds
        let screenWidth = screensize.width
        let screenHeight = screensize.height

        //context
        let context = UIGraphicsGetCurrentContext()
        CGContextSetLineWidth(context, 7.0)
        CGContextSetStrokeColorWithColor(context, UIColor.whiteColor().CGColor)

        //path
        CGContextMoveToPoint(context, screenWidth, screenHeight * 0.5)
        CGContextAddLineToPoint(context, screenWidth * 0.5, screenHeight * 0.5)

        CGContextSetLineCap(context, CGLineCap.Round)

        //draw
        CGContextStrokePath(context)

    }

}

我问的原因是我发现我无法为它设置动画,因为它在drawRect函数中.真的吗？需要你们的一些解释.谢谢!