alert - iOS8 中的 "Please wait"对话框

Question

我以前有一个 “请稍等”我的应用程序中的对话框很长一段时间。使用 UIActivityIndicatorView 很简单并将其添加到 UIAlertView .

然而iOS8引入了UIAlertController .是否可以添加任何东西以产生类似的效果？有没有其他方法可以用 iOS8 做这样的事情？

我搜索了很多网站，但仍然不知道如何使用新 API 来完成。

我将不胜感激任何答案 - 指向库、教程等的链接，这可能会有所帮助。

问候，

马特乌斯

Answer 1

您可以使用模态呈现的自定义 UIViewController，而不是使用 UIAlertController。这是我在 Swift 2.0 中使用的:

class ActivityViewController: UIViewController {

    private let activityView = ActivityView()

    init(message: String) {
        super.init(nibName: nil, bundle: nil)
        modalTransitionStyle = .CrossDissolve
        modalPresentationStyle = .OverFullScreen
        activityView.messageLabel.text = message
        view = activityView
    }

    required init(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

private class ActivityView: UIView {

    let activityIndicatorView = UIActivityIndicatorView(activityIndicatorStyle: .WhiteLarge)
    let boundingBoxView = UIView(frame: CGRectZero)
    let messageLabel = UILabel(frame: CGRectZero)

    init() {
        super.init(frame: CGRectZero)

        backgroundColor = UIColor(white: 0.0, alpha: 0.5)

        boundingBoxView.backgroundColor = UIColor(white: 0.0, alpha: 0.5)
        boundingBoxView.layer.cornerRadius = 12.0

        activityIndicatorView.startAnimating()

        messageLabel.font = UIFont.boldSystemFontOfSize(UIFont.labelFontSize())
        messageLabel.textColor = UIColor.whiteColor()
        messageLabel.textAlignment = .Center
        messageLabel.shadowColor = UIColor.blackColor()
        messageLabel.shadowOffset = CGSizeMake(0.0, 1.0)
        messageLabel.numberOfLines = 0

        addSubview(boundingBoxView)
        addSubview(activityIndicatorView)
        addSubview(messageLabel)
    }

    required init(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func layoutSubviews() {
        super.layoutSubviews()

        boundingBoxView.frame.size.width = 160.0
        boundingBoxView.frame.size.height = 160.0
        boundingBoxView.frame.origin.x = ceil((bounds.width / 2.0) - (boundingBoxView.frame.width / 2.0))
        boundingBoxView.frame.origin.y = ceil((bounds.height / 2.0) - (boundingBoxView.frame.height / 2.0))

        activityIndicatorView.frame.origin.x = ceil((bounds.width / 2.0) - (activityIndicatorView.frame.width / 2.0))
        activityIndicatorView.frame.origin.y = ceil((bounds.height / 2.0) - (activityIndicatorView.frame.height / 2.0))

        let messageLabelSize = messageLabel.sizeThatFits(CGSizeMake(160.0 - 20.0 * 2.0, CGFloat.max))
        messageLabel.frame.size.width = messageLabelSize.width
        messageLabel.frame.size.height = messageLabelSize.height
        messageLabel.frame.origin.x = ceil((bounds.width / 2.0) - (messageLabel.frame.width / 2.0))
        messageLabel.frame.origin.y = ceil(activityIndicatorView.frame.origin.y + activityIndicatorView.frame.size.height + ((boundingBoxView.frame.height - activityIndicatorView.frame.height) / 4.0) - (messageLabel.frame.height / 2.0))
    }
}

你像这样使用它:

let activitiyViewController = ActivityViewController(message: "Loading...")
presentViewController(activitiyViewController, animated: true, completion: nil)

它看起来像这样:



演示 Controller 和动画过渡

看到这个 answer对于重新创建 UIAlertController 的示例实现动画使用 UIViewControllerAnimatedTransitioning .