如何在Swift中逐点绘制线

Question

我意识到自己在跟踪器应用程序中滥用了从服务器检索的数据。 所以我有这个：

 @objc private func updateOnlineTrackWithNewData() {

    print("Tick")

    if let track = track {

        guard track.status == 1 else { return } // is track online?

        serverManager.tracks.updateOnlineTrack(for: track, success: { (trackNewPoints) in 
       //receive new data

            guard trackNewPoints.count > 1 else { return }

            for point in trackNewPoints {

                self.track?.points?.append(point)

                self.performSelector(onMainThread: #selector(self.updateOnlineTrackOnMap), with: nil, waitUntilDone: true)

            }

        }) { (error) in

            print(error ?? "Error updating online track")

           }
    }
}

trackNewPoints基本上是我要附加到主“ track”上的点的数组，而updateOnlineTrackOnMap只是将其打印出来。 updateOnlineTrackWithNewData（）函数由计时器触发，一切正常。 但是我想逐点绘制线以模拟实时运动。 我该如何实现？ performSelector似乎不起作用。

如果有帮助，每10秒我会获得10个新点。

Answer 1

有一种方法可以做到这一点。 创建单独的类抽屉

protocol Drawable { // add to your controller 
    func appendPoint(_ point: AnyObject)
    func updateOnlineTrackOnMap()
}

class Drawer {

    private var timer: Timer? = nil
    private var points: [AnyObject] = []

    func drawPoints(_ points: [AnyObject],
                    controller: Drawable) {
        self.points = points
        timer = Timer.scheduledTimer(withTimeInterval: 1, repeats: true) { [weak self] timer in
            guard let point = self?.points.first else {
                timer.invalidate()
                return
            }
            DispatchQueue.global(qos: .userInteractive).async {
                controller.appendPoint(point)
                controller.updateOnlineTrackOnMap()
                self?.points.remove(at: 0)
            }
        }
    }
}