如何在tableView加载时显示活动指示器？ [英] How to show activity indicator while tableView loads?

问题描述

当我在我的标签之间切换时，它会加载几秒钟，我想知道我的数据正在加载。为此我决定添加一个活动指标。

When I switch between my tabs it loads some seconds and I want to know that my data is loading. For that I decided to add an activity indicator.

我写了一个小函数：

func showActivityIndicator() {
    dispatch_async(dispatch_get_main_queue()) {
        self.spinner = UIActivityIndicatorView(activityIndicatorStyle: .WhiteLarge)
        self.spinner.frame = CGRect(x: 0.0, y: 0.0, width: 80.0, height: 80.0)
        self.spinner.center = CGPoint(x:self.loadingView.bounds.size.width / 2, y:self.loadingView.bounds.size.height / 2)

        self.loadingView.addSubview(self.spinner)
        self.view.addSubview(self.loadingView)
        self.spinner.startAnimating()
    }
}

将显示我的指标。当我从infoController中点击按钮时尝试使用它：

that will show my indicator. And try to use it when I tapped from my infoController to button:

@IBAction func goToMainFromInfo(sender: AnyObject) {
        self.showActivityIndicator()
        self.performSegueWithIdentifier("fromMainToInfoWActivity", sender: nil)
        self.hideActivityIndicator()
    }
}

我在segue执行之前显示它并在之后隐藏。它对我没有帮助。当我尝试使用同步时：

I show it before segue perform and hide after. It doesn't help me. When I did try to use sync:

@IBAction func goToMainFromInfo(sender: AnyObject) {
    dispatch_async(dispatch_get_main_queue()) {
        self.showActivityIndicator()
        self.performSegueWithIdentifier("fromMainToInfoWActivity", sender: nil)
        self.hideActivityIndicator()
    }
}

但它也没有帮助。当我按Tab键时，不透明度变为0.5，我在加载时等待。但我没有看到我的活动指标。

But it doesn't help too. When I press to tab it opacity becomes 0.5 and I wait while it loading. But I do not see my activity indicator.

有什么问题？

推荐答案

试试这个：

var indicator = UIActivityIndicatorView()

func activityIndicator() {
    indicator = UIActivityIndicatorView(frame: CGRectMake(0, 0, 40, 40))
    indicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.Gray
    indicator.center = self.view.center
    self.view.addSubview(indicator)    
}

您想要开始动画的地方

indicator.startAnimating()
indicator.backgroundColor = UIColor.whiteColor()

止损：

indicator.stopAnimating()
indicator.hidesWhenStopped = true

注意：避免同时调用start和stop 。只是给出一些条件。

Note: Avoid the calling of start and stop in same time. Just give some conditions.

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