UIActivityIndicatorView display in the center of the screen

Is there a way to have the UIActivityIndicatorView display in the center of the screen to mirror the NetworkActivityIndicator? So I want the same process as the NetworkAc开发者_JAVA技巧tivityIndicator, just with a larger indicator that will be more noticeable to the user.

Try this:

UIView *view = /* whatever your main view is */
UIActivityIndicatorView *spinner = [[UIActivityIndicatorVIew alloc] 
            initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
CGRect frame = spinner.frame;
frame.origin.x = view.frame.size.width / 2 - frame.size.width / 2;
frame.origin.y = view.frame.size.height / 2 - frame.size.height / 2;
spinner.frame = frame;
[view addSubview:spinner];
[spinner startAnimating];
[spinner release]; // Or, you could keep a handle to this for later to stop animating it

This basically centers the spinner in its enclosing view, whatever that might be.

If you do not keep a handle to spinner, and if spinner is the only subview of view (or at least in a well known position), you could later get a handle to it by dipping into [view subviews] for it.

EDIT: You could also probably use CGRectGetMidX() and CGRectGetMidY() instead of the more complicated equations above for finding x and y... Your mileage may vary. :-)

EDIT (2/25/2016)

This answer has received some up-votes recently, so I thought an update was in order. There is actually an even better way to do this now. This example places a UIActivityIndicatorView in the center of a UITableView.

self.spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
_spinner.translatesAutoresizingMaskIntoConstraints = NO;
_spinner.hidesWhenStopped = YES;
[self.tableView addSubview:self.spinner];

[self.tableView addConstraints:@[
                                 [NSLayoutConstraint constraintWithItem:_spinner
                                                              attribute:NSLayoutAttributeCenterX
                                                              relatedBy:NSLayoutRelationEqual
                                                                 toItem:self.tableView
                                                              attribute:NSLayoutAttributeCenterX
                                                             multiplier:1 constant:0],
                                 [NSLayoutConstraint constraintWithItem:_spinner
                                                              attribute:NSLayoutAttributeCenterY
                                                              relatedBy:NSLayoutRelationEqual
                                                                 toItem:self.tableView
                                                              attribute:NSLayoutAttributeCenterY
                                                             multiplier:1 constant:0]
                                 ]];

This works for me inside a UIViewController:

override func viewDidLayoutSubviews() {
    activityIndicator.center = view.center
}

indicatorView.autoresizingMask = UIViewAutoresizingFlexibleBottomMargin|UIViewAutoresizingFlexibleTopMargin|UIViewAutoresizingFlexibleLeftMargin|UIViewAutoresizingFlexibleRightMargin;
indicatorView.center = self.view.center;

activityInd.center = CGPointMake(160,240);

-(void)setCenter:(UIView*)view{
UIActivityIndicatorView *actView = [[UIActivityIndicatorView alloc]initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
[view addSubview:actView];
[actView startAnimating];
CGSize boundsSize = view.bounds.size;
CGRect frameToCenter = actView.frame;
// center horizontally
if (frameToCenter.size.width < boundsSize.width)
    frameToCenter.origin.x = (boundsSize.width - frameToCenter.size.width) / 2;
else
    frameToCenter.origin.x = 0;

// center vertically
if (frameToCenter.size.height < boundsSize.height)
    frameToCenter.origin.y = (boundsSize.height - frameToCenter.size.height) / 2;
else
    frameToCenter.origin.y = 0;

actView.frame = frameToCenter;

}

In Swift:

var activityIndicator = UIActivityIndicatorView(activityIndicatorStyle: UIActivityIndicatorViewStyle.Gray)

override func viewDidLoad() {
    activityIndicator.hidesWhenStopped = true;
    activityIndicator.activityIndicatorViewStyle  = UIActivityIndicatorViewStyle.Gray;
    activityIndicator.center = view.center;
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
}

For more information refer the below tutorial:

http://sourcefreeze.com/uiactivityindicatorview-example-using-swift-in-ios/

This worked for me. Notice I use bounds rather than frame. The frame properly doesn't always show the rect based on the orientation (this method goes inside the view controller).

- (void) viewDidLayoutSubviews
{
    if (self.spinner)
    {
        CGRect screenRect = self.view.bounds;

        self.spinner.frame = CGRectMake(roundf((screenRect.size.width - 50) * 0.5f),
                                        roundf((screenRect.size.height - 50) * 0.5f),
                                        50,
                                        50);
    }
}

Only this work perfect for me, simple and fast:

UIActivityIndicatorView *spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray]; 

spinner.center = CGPointMake(self.view.frame.size.width/2, self.view.frame.size.height/2);

[self.view addSubview:spinner]; 
[spinner startAnimating];

in swift 2.0 xcode 7:

 override func viewDidLayoutSubviews() {
    self.Loader.center = self.view.center
 }