Below is a template for the singletons that we use in objective-c.
MySingleton.h:
#import <Foundation/Foundation.h>
@interface MySingleton : NSObject {
}
+(MySingleton*)sharedMySingleton;
-(void)sayHello;
@end
MySingleton.m:
@implementation MySingleton
static MySingleton* _sharedMySingleton = nil;
+(MySingleton*)sharedMySingleton
{
@synchronized([MySingleton class])
{
if (!_sharedMySingleton)
[[self alloc] init];
return _sharedMySingleton;
}
return nil;
}
+(id)alloc
{
@synchronized([MySingleton class])
{
NSAssert(_sharedMySingleton == nil, @"Attempted to allocate a second instance of a singleton.");
_sharedMySingleton = [super alloc];
return _sharedMySingleton;
}
return nil;
}
-(id)init {
self = [super init];
if (self != nil) {
// initialize stuff here
}
return self;
}
-(void)sayHello {
NSLog(@"Hello World!");
}
@end