ios - 如何以编程方式在视图中间创建活动指示器？

Question

我正在使用一个在线解析提要的应用程序。当我单击刷新按钮时，需要一些时间来重新解析文件并显示其数据。当我单击刷新按钮时，我希望在视图中间有一个活动指示器。解析完成后，该指示器应隐藏。

我正在使用此代码，但它不起作用：

- (IBAction)refreshFeed:(id)sender
{
   UIActivityIndicatorView *spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
   [self.view addSubview:spinner];

   [spinner startAnimating];

   // parsing code code
    
   [spinner release];
}

score 17 · Accepted Answer

UIActivityIndicator 通常需要从长进程（解析提要）放入单独的线程中才能出现。

如果您想将所有内容保持在同一个线程中，那么您需要给指标时间出现。这个 Stackoverflow 问题解决了代码中的延迟问题。

编辑：两年后，我认为任何时候你使用延迟来让事情发生，你可能做错了。以下是我现在将如何执行此任务：

- (IBAction)refreshFeed:(id)sender {
    //main thread
    UIActivityIndicatorView *spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge]; [self.view addSubview:spinner];

    //switch to background thread
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{

        //back to the main thread for the UI call
        dispatch_async(dispatch_get_main_queue(), ^{
            [spinner startAnimating];
        });
        // more on the background thread

        // parsing code code

        //back to the main thread for the UI call
        dispatch_async(dispatch_get_main_queue(), ^{
            [spinner stopAnimating];
        });
    });
}

score 13 · Accepted Answer

我想我无法很好地解释它。好吧，让我们再试一次。它是一个基于导航的应用程序。我有表视图。每个单元格都会创建一个 detailView。在作为表格视图的 RootView 上有一个刷新按钮。当我单击该按钮时，它会再次解析提要。这需要一些时间。因为那个时候程序没有响应。并且解析完成它再次工作。现在我需要那个时候的活动指示器。我不知道如何在 xib 中添加。bcz 当我打开 main.xib 并将活动指示器放入 RootViewController 时。它出现在整个 tableView 的前面。现在可能我解释得很好。如果不让我知道，我会再试一次。

从您上面所说的来看，程序在解析过程中没有响应，这是一个问题。如果在解析数据时 GUI 冻结，则应将该操作移至辅助线程。这样，您的 GUI 将保持响应，并且您将能够看到活动指示器。

在主线程上，您应该有类似的东西以显示活动指示器：

UIActivityIndicatorView  *av = [[[UIActivityIndicatorView alloc]initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray] autorelease];
av.frame = CGRectMake(round((yourView.frame.size.width - 25) / 2), round((yourView.frame.size.height - 25) / 2), 25, 25);
av.tag  = 1;
[yourView addSubview:av];
[av startAnimating];

辅助线程完成后，这是您解析数据的线程，您应该在主线程上调用类似这样的方法来删除活动指示器：

UIActivityIndicatorView *tmpimg = (UIActivityIndicatorView *)[yourView viewWithTag:1];
[tmpimg removeFromSuperview];

score 7 · Accepted Answer

7

将活动指示器的中心更改为

activityIndicator.center = self.view.center;

于 2011-02-24T10:21:37.183 回答

score 7 · Accepted Answer

UIActivityIndicatorView *activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
activityIndicator.alpha = 1.0;
[collectionVwSearch addSubview:activityIndicator];
activityIndicator.center = CGPointMake([[UIScreen mainScreen]bounds].size.width/2, [[UIScreen mainScreen]bounds].size.height/2);
[activityIndicator startAnimating];//to start animating

对于斯威夫特

let activityIndicator: UIActivityIndicatorView = UIActivityIndicatorView.init(activityIndicatorStyle: UIActivityIndicatorViewStyle.Gray)
activityIndicator.alpha = 1.0
collectionVwSearch.addSubview(activityIndicator)
activityIndicator.center = CGPointMake(UIScreen.mainScreen().bounds.size.width / 2, UIScreen.mainScreen().bounds.size.height / 2)
activityIndicator.startAnimating()

停止活动指示器写[activityIndicator stopAnimating]在适当的地方

score 2 · Accepted Answer

self.activity.center = CGPointMake(self.view.bounds.size.width / 2.0f, self.view.bounds.size.height / 2.0f);
self.activity.autoresizingMask = (UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleBottomMargin | UIViewAutoresizingFlexibleTopMargin);

score 1 · Accepted Answer

在开始您的任务之前添加此代码：

UIActivityIndicatorView *spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
[self.view addSubview:spinner];
[spinner setFrame:CGRectMake((self.view.frame.size.width/2)-(spinner.frame.size.width/2), (self.view.frame.size.height/2)-(spinner.frame.size.height/2), spinner.frame.size.width, spinner.frame.size.height)];
[spinner startAnimating];

完成任务后添加：

[spinner stopAnimating];

score 1 · Accepted Answer

在 Swift 中，这适用于我的应用

let activity_view = UIActivityIndicatorView(activityIndicatorStyle: UIActivityIndicatorViewStyle.Gray)
activity_view.frame =  CGRectMake(0.0, 0.0, 40.0,40.0)
activity_view.center = self.view.center
self.view.addSubview(activity_view)
activity_view.bringSubviewToFront(self.view)
activity_view.startAnimating()

score 0 · Accepted Answer

0

试试这样

activityIndicator.center = CGPointMake(160,240);

于 2011-02-24T10:50:40.783 回答

score 0 · Accepted Answer

/ create activity indicator 
activityIndicator = [[UIActivityIndicatorView alloc] 
    initWithFrame:CGRectMake(0.0f, 0.0f, 20.0f, 20.0f)];
[activityIndicator setActivityIndicatorViewStyle:UIActivityIndicatorViewStyleWhite];

...
 [self.view addSubview:activityIndicator];
// release it
[activityIndicator release];

更好的方法是在 xib 上添加指示符并根据您的要求隐藏/取消隐藏

score 0 · Accepted Answer

spinner.center = self.view.center;

要从 rootController 显示微调器，请尝试：

[self.navigationController.visibleViewController.view addSubview:spinner];

或者

[self.navigationController.view addSubview:spinner];

score 0 · Accepted Answer

斯威夫特 5

宣言

let activityIndicator: UIActivityIndicatorView = UIActivityIndicatorView.init(style: UIActivityIndicatorView.Style.medium)
//if you want a bigger activity indicator, change style from .medium to .large

ViewDidLoad

activityIndicator.alpha = 1.0
view.addSubview(activityIndicator)
activityIndicator.center = view.center

激活活动指示器，在我的情况下，它在 `didSelectRowAt` 方法中

activityIndicator.startAnimating()

如果您在动画处于活动状态时推送到另一个 viewController，然后弹回，您仍然会看到活动指示器动画，所以您应该这样做

override func viewWillAppear(_ animated: Bool) {
        if activityIndicator.isAnimating {
            activityIndicator.stopAnimating()
        }
    }

score 0 · Accepted Answer

其他一些答案的问题是每次都会添加一个新的活动指示器，因此子视图开始堆积。这是一个仅使用单个UIActivityIndicator.

这是上面项目的完整代码：

import UIKit
class ViewController: UIViewController {

    // only using a single spinner instance
    let spinner = UIActivityIndicatorView(activityIndicatorStyle: .WhiteLarge)

    override func viewDidLoad() {
        super.viewDidLoad()

        // setup spinner
        spinner.backgroundColor = UIColor(white: 0, alpha: 0.2) // make bg darker for greater contrast
        self.view.addSubview(spinner)
    }

    @IBAction func startSpinnerButtonTapped(sender: UIButton) {

        // start spinner
        spinner.frame = self.view.frame // center it
        spinner.startAnimating()

        let qualityOfServiceClass = QOS_CLASS_BACKGROUND
        let backgroundQueue = dispatch_get_global_queue(qualityOfServiceClass, 0)
        dispatch_async(backgroundQueue, {       

            // do something that takes a long time
            sleep(2)

            // stop spinner when background task finishes
            dispatch_async(dispatch_get_main_queue(), { () -> Void in
                self.spinner.stopAnimating()
            })
        })
    }
}

score 0 · Accepted Answer

你可以写 swift 4

let spinner = UIActivityIndicatorView(activityIndicatorStyle: .whiteLarge)

override func viewDidLoad() {
    super.viewDidLoad()

    spinner.backgroundColor = UIColor(white: 0, alpha: 0.2) // make bg darker for greater contrast
    self.view.addSubview(spinner)
}

@IBAction func foodActionBtn(_ sender: Any) {

    // start spinner
    spinner.frame = self.view.frame // center it
    spinner.startAnimating()

    let qualityOfServiceClass = QOS_CLASS_BACKGROUND
    let backgroundQueue = DispatchQueue.global(qos: .background)
    backgroundQueue.async(execute: {
        sleep(2)
        self.spinner.stopAnimating()
    })
}

score -2 · Accepted Answer

Poscean 先生，我的代码正在运行。但是你想显示活动指示器的大出现吗？你可以使用它....

var activityIndicator = UIActivityIndicatorView()
    activityIndicator = UIActivityIndicatorView(activityIndicatorStyle: UIActivityIndicatorViewStyle.gray)
    activityIndicator.frame = CGRect(x: 0, y: 0, width: 50, height: 50)
    let transform: CGAffineTransform = CGAffineTransform(scaleX: 1.5, y: 1.5)
    activityIndicator.transform = transform
    activityIndicator.center = self.view.center
    activityIndicator.startAnimating()
    self.view.addSubview(activityIndicator)

ios - 如何以编程方式在视图中间创建活动指示器？

14 回答 14

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