Я обновляю ответ jonsibley , добавляя поддержку для случаев, когда UISearchBar встроен в UINavigationBar с использованием displaySearchBarInNavigationBar flag.
SearchBarWithActivity.h (добавлено новое свойство):
@interface SearchBarWithActivity : UISearchBar
- (void)startActivity; // increments startCount and shows activity indicator
- (void)finishActivity; // decrements startCount and hides activity indicator if 0
@property (nonatomic,assign) UINavigationItem *navigationItem;
@end
SearchBarWithActivity.m (получить searchField из элемента навигации, если не ноль):
#import "SearchBarWithActivity.h"
@interface SearchBarWithActivity()
@property(nonatomic) UIActivityIndicatorView *activityIndicatorView;
@property(nonatomic) int startCount;
@end
@implementation SearchBarWithActivity
@synthesize navigationItem;
- (void)layoutSubviews {
UITextField *searchField = nil;
if(self.navigationItem) {
searchField = (UITextField *)[self.navigationItem titleView];
} else {
for(UIView* view in self.subviews){
// on iOS 6, the UITextField is one-level deep
if ([view isKindOfClass:[UITextField class]]){
searchField= (UITextField *)view;
break;
}
// on iOS 7, the UITextField is two-levels deep
for (UIView *secondLevelSubview in view.subviews) {
if([secondLevelSubview isKindOfClass:[UITextField class]]){
searchField= (UITextField *)secondLevelSubview;
break;
}
}
}
}
if(searchField) {
if (!self.activityIndicatorView) {
UIActivityIndicatorView *taiv = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
taiv.center = CGPointMake(searchField.leftView.bounds.origin.x + searchField.leftView.bounds.size.width/2,
searchField.leftView.bounds.origin.y + searchField.leftView.bounds.size.height/2);
taiv.hidesWhenStopped = YES;
self.activityIndicatorView = taiv;
_startCount = 0;
[searchField.leftView addSubview:self.activityIndicatorView];
}
}
[super layoutSubviews];
}
- (void)startActivity {
self.startCount = self.startCount + 1;
}
- (void)finishActivity {
self.startCount = self.startCount - 1;
}
- (void)setStartCount:(int)startCount {
_startCount = startCount;
if (_startCount > 0) {
[self.activityIndicatorView startAnimating];
// Remove the "magnifying glass icon"
[self setImage:[UIImage new] forSearchBarIcon:UISearchBarIconSearch state:UIControlStateNormal];
} else {
[self.activityIndicatorView stopAnimating];
// Restore the "magnifying glass icon"
[self setImage:nil forSearchBarIcon:UISearchBarIconSearch state:UIControlStateNormal];
}
}
@end
В вашем ViewController:
#import "SearchBarWithActivity.h"
- (void)viewDidLoad
{
[super viewDidLoad];
// Embed the search bar into NavigationBar and setup the navigation item in order to show the spinner
[self.searchDisplayController setDisplaysSearchBarInNavigationBar:YES];
[(SearchBarWithActivity *)self.searchDisplayController.searchBar setNavigationItem:self.navigationItem];
}
Надеюсь, это сэкономит кому-то время.