Add UIActivityIndicatorView into UIBarButton

问题:

How do I add a UIActivityIndicatorView spinner circle into a UIBarButton, so that when a user taps on one of those buttons on the navigation bar, they see a spinner while the loading takes place?

回答1:

If you're trying to show the activity wheel in a navigation bar button (e.g. you might have a refresh button on your navbar) - you can create a new UIBarButtonItem with a custom view being the UIActivityIndicatorView:

Objective-C

uiBusy = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
uiBusy.hidesWhenStopped = YES;
[uiBusy startAnimating];
[self.navigationItem.rightBarButtonItem initWithCustomView:uiBusy];

Swift

let uiBusy = UIActivityIndicatorView(activityIndicatorStyle: .White)
uiBusy.hidesWhenStopped = true
uiBusy.startAnimating()
self.navigationItem.rightBarButtonItem = UIBarButtonItem(customView: uiBusy)

This overwrites your rightBarButtonItem with the spinning wheel. When you're done, just recreate the rightBarButtonItem.

回答2:

activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
activityIndicator.hidesWhenStopped = YES;
self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:activityIndicator];

Place the following where ever is needed:

[activityIndicator startAnimating];
[activityIndicator stopAnimating];

回答3:

Actually activity indicator is not added as toolbar item. It's a subview of current view.

    UIActivityIndicatorView *act = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
    [act setCenter:CGPointMake(20, 20)];
    [act startAnimating];
    [self.view addSubview:act];

Remember to release it in -(void)dealloc.

回答4:

Use this Methods

-(void)startAniatingActivityIndicator{
@try {
    activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
    activityIndicator.frame = CGRectMake(self.window.frame.size.width-30, 32.5, activityIndicator.bounds.size.width, activityIndicator.bounds.size.height);
    [self.window addSubview:activityIndicator];
    [activityIndicator startAnimating];
    [self.window bringSubviewToFront:activityIndicator];
}
@catch (NSException *exception) {

}
@finally {

}

}

-(void)stopAniatingActivityIndicator{
[activityIndicator stopAnimating];
[activityIndicator removeFromSuperview];
activityIndicator = nil;

}

回答5:

UIActivityIndicatorView is a type of view. Set its frame to be within your button and use -addSubview to add it to the view hierarchy of the UIBarButton.

I'm oversimplifying, since you have to try to make it fit the space (possibly by scaling) and center it...

回答6:

pseudocode, i'm not going to check this in Xcode, but something like this should work:

UIActivityIndicatorView *act = [[UIActivityIndicatorView alloc] init];
act.frame = CGMakeRect(3,3,25,25);
[myBarButton addSubview:act];
[act release];