带有提示和活动指示器的 UINavigationItem [英] UINavigationItem with prompt and activity indicator

问题描述

我想知道 Apple 是如何在标题上方实现包含活动指示器(见下图)的 UINavigationItem.这是允许这样做的Apple私有API吗?如果不是，如何在应用程序中重现.

I'm wondering how Apple implemented the UINavigationItem that contains an activity indicator (see attached image below), above the title. Is this Apple's private API that allows to do that? If not, how can it be reproduced in an application.

UINavigationItem 带有提示和活动指示器 http://img218.imageshack.us/img218/8819/img0133g.png

谢谢！

推荐答案

我用这段代码得到了和你的截图完全相同的渲染:

I got the exact same rendering than your screenshot with this code:

 UIView                      *viewContainingSpinner;
    UIActivityIndicatorView     *activityIndicatorView;
    UIBarButtonItem             *activityButtonItem;
    UIBarButtonItem             *rightBarButtonItem;


    // Configuring the title and the prompt title of the navigation bar
    [self.navigationItem setTitle:@"MobileMe"];
    [self.navigationItem setPrompt:@"Vérification du compte MobileMe"];

    // We will create a UIBarButtonItem that has a custom view (viewContainingSpinner).
    // A subview of viewContainingSpinner will be a UIActivityIndicatorView (activityIndicatorView)
    // We need to have this "intermediate" view to position the spinner at the right position (the UIBarButtonItem ignores the origin and height of its custom view)
    viewContainingSpinner = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 60, 85)];
    activityIndicatorView = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(20, 0, 20, 20)];
    [viewContainingSpinner addSubview:activityIndicatorView];
    [activityIndicatorView startAnimating];
    [activityIndicatorView release];

    activityButtonItem = [[UIBarButtonItem alloc] initWithCustomView:viewContainingSpinner];
    self.navigationItem.leftBarButtonItem = activityButtonItem;
    [viewContainingSpinner release];
    [activityButtonItem release];

    // Finally, configuring the right button
    rightBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Enregistrer" style:UIBarButtonItemStylePlain target:nil action:nil];
    [rightBarButtonItem setEnabled:NO];
    self.navigationItem.rightBarButtonItem = rightBarButtonItem;
    [rightBarButtonItem release];

PS:在实际应用程序中，我建议不要在代码中使用本地化字符串.验证"一词的 é 可能会给您带来麻烦.看看方法 NSLocalizedString.

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