text: #import <UIKit/UIKit.h>
  
  /**
   Activity indicator as used by PurchaseButton. Shows a rotating arc.
   */
  @interface PurchaseActivityIndicatorView : UIView
  
  @property (nonatomic, assign) CGFloat lineWidth;
  
  - (void)startAnimating;
  - (void)stopAnimating;
  - (BOOL)isAnimating;
  
  @end
  