ios - swift 3 : How to animate a view background color similar to a progress bar

Question

当用户进入包含下图的 View Controller 时，我希望根据值(在本例中为 70)对蓝色进行动画处理。这意味着，颜色从 View 中的 0px 开始加载，并且停止在任何值的数量上。另外，我希望在加载颜色的同时，数字从 0 计数到最终值。为了实现这一目标，您是否有任何提示/链接或方向可以指导我？提前致谢!

Answer 1

使用所需的backgroundColor创建progressView

let progressView = UIView(frame: CGRect(x: 0, y: 0, width: 1, height: 50))
progressView.backgroundColor = .blue
self.view.addSubview(progressView)

调用以下函数使其宽度与 progress

成比例

func setProgress(_ progress: CGFloat) {
    let fullWidth: CGFloat = 200
    let newWidth = progress/100*fullWidth
    UIView.animate(withDuration: 1.5) {
        self.progressView.frame.size = CGSize(width: newWidth, height: self.progressView.frame.height)
    }
}

创建一个progressLabel 和一个currentProgress 变量

let progressLabel = UILabel(frame: CGRect(x: 0, y: 100, width: 50, height: 50))
var currentProgress: CGFloat = 0
label.text = String(currentProgress)
self.view.addSubview(progressLabel)

调用以下函数以延迟循环更新其进度，示例:setLabelProgress(initialValue: self.currentProgress, targetValue: 70)

func setLabelProgress(initialValue: CGFloat, targetValue: CGFloat) {

    guard currentProgress != targetValue else { return }

    let range = targetValue - initialValue
    let increment = range/CGFloat(abs(range))
    let duration: TimeInterval = 1.5
    let delay = duration/TimeInterval(range)
    currentProgress += increment
    progressLabel.text = String(describing: currentProgress)

    DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + delay) {
        self.setLabelProgress(initialValue: initialValue, targetValue: targetValue)
    }
}

对于第二个标签调用相同的函数，但交换 initialValue 和 targetValue