在应用程序启动期间显示活动指示器 [英] Show activity indicator during application launch

问题描述

我正在尝试在启动期间添加活动指示器。我确实有一个发射图像，但我宁愿只有一个指标。

I am trying to add an activity indicator during startup. I did have a launch image, but I'd rather have just an indicator alone. I added the following to my app delegate, but the indicator doesn't appear.

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // *******Create activity indicator****
    UIActivityIndicatorView *activity = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(225, 115, 30, 30)];
    [activity setBackgroundColor:[UIColor clearColor]];
    [activity setActivityIndicatorViewStyle: UIActivityIndicatorViewStyleGray];
    [window addSubview: activity];
    [activity release];

    [activity startAnimating];
    activity.hidden = FALSE;
    // *******End activity indicator****

    MainViewController *viewController = [[MainViewController alloc] initWithNibName:@"MainView" bundle:nil];
    self.mainViewController = viewController;

    [window addSubview:[mainViewController view]];
    mainViewController.view.frame = CGRectMake(0, 20, 320, 411);

    [window addSubview:[rootController view]];
    [window makeKeyAndVisible];
#if !TARGET_IPHONE_SIMULATOR
    [application registerForRemoteNotificationTypes: 
     UIRemoteNotificationTypeAlert | UIRemoteNotificationTypeBadge | UIRemoteNotificationTypeSound];
#endif

    application.applicationIconBadgeNumber = 0;

    // Hide indicator
    [viewController release];
    activity.hidden = TRUE;

    [activity stopAnimating];
    return YES;
}

我在2009年访问了这个问题，但解决方案没有工作为了我。
iPhone-SDK：启动期间的活动指示？

推荐答案

我不认为这是可能从查看 UIApplicationDelegate

I don't think this is possible from looking at the docs for UIApplicationDelegate

您的应用程序最早被调用是在

The earliest your app is called is in

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

顾名思义，当你的应用程序 hasFinishedLaunching

Which as the name suggests is when your app hasFinishedLaunching

当你显示和隐藏指标时，没有什么发生的原因是线程。用户界面只会在您的方法结束时更新，其中更改的最终结果是指标隐藏。

The reason nothing happens when you show and hide the indicator is to do with threading. The user interface will only update at the end of your method where the net result of your changes will be that the indicator is hidden.

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