UIActivityIndicatorView display in the center of the screen

Question

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 NetworkActivityIndicator, just with a larger indicator that will be more noticeable to the user.

Answer 1

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]
                                 ]];

Answer 2

This works for me inside a UIViewController:

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

Answer 3

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