Can I change the size of UIActivityIndicator?

问题:

Whatever size i give to it while allocation, it shows fixed size only. Is it possible to increase it?

Code:

activityIndicator = [[UIActivityIndicatorView alloc] initWithFrame:
                     CGRectMake(142.00, 212.00, 80.0, 80.0)];
[[self view] addSubview:activityIndicator];
[activityIndicator sizeToFit];
activityIndicator.autoresizingMask = (UIViewAutoresizingFlexibleLeftMargin |
                                      UIViewAutoresizingFlexibleRightMargin |
                                      UIViewAutoresizingFlexibleTopMargin |
                                      UIViewAutoresizingFlexibleBottomMargin);
activityIndicator.hidesWhenStopped = YES;
activityIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyleWhiteLarge;

回答1:

The size is fixed by the style. It's a standardized interface element so the API doesn't like to fiddle with it.

However, you probably could do a scaling transform on it. Not sure how that would affect it visually, however.

Just from a UI design perspective, its usually better to leave these common standardized elements alone. User have been taught that certain elements appear in a certain size and that they mean specific things. Altering the standard appearance alters the interface grammar and confuses the user.

回答2:

The following will create an activity indicator 15px wide:

#import <QuartzCore/QuartzCore.h>

...

UIActivityIndicatorView *activityIndicator = [[[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray] autorelease];
activityIndicator.transform = CGAffineTransformMakeScale(0.75, 0.75);
[self addSubview:activityIndicator];

While I understand the sentiment of TechZen's answer, I don't think adjusting the size of a UIActivityIndicator by a relatively small amount is really a violation of Apple's standardized interface idioms - whether an activity indicator is 20px or 15px won't change a user's interpretation of what's going on.

回答3:

It is possible to resize UIActivityIndicator.

CGAffineTransform transform = CGAffineTransformMakeScale(1.5f, 1.5f);
activityIndicator.transform = transform;

Original size is 1.0f. Now you increase and reduce size accordingly.

回答4:

Swift 3.0 & Swift 4.0

self.activityIndi.transform = CGAffineTransform(scaleX: 3, y: 3)

回答5:

Swift3

 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)

回答6:

Here is an extension that would work with Swift 3.0 & checks to prevent 0 scaling (or whatever value you want to prohibit):

extension UIActivityIndicatorView {
    func scale(factor: CGFloat) {
        guard factor > 0.0 else { return }

        transform = CGAffineTransform(scaleX: factor, y: factor)
    }
}

Call it like so to scale to 40 pts (2x):

activityIndicatorView.scale(factor: 2.0)

回答7:

There also are lots of other useful "CGAffineTransform" tricks you can play with. For more details please see Apple Developer Library reference:

http://developer.apple.com/library/mac/#documentation/GraphicsImaging/Reference/CGAffineTransform/Reference/reference.html

Good luck!

回答8:

The best you can do is use the whiteLarge style. let i = UIActivityIndicatorView(activityIndicatorStyle: UIActivityIndicatorViewStyle.whiteLarge).

Increasing the size of UIActivityIndicatorView does not change the size of the indicator proper, as you can see in these pictures.