IOS – NSTIMER Category Blocks Replacement Selector

// NSTimer+Additions.h

# import 

typedef void (^VoidBlock)();

@interface NSTimer (NSTimer_Additions)


+ (NSTimer *)scheduleTimerWithTimeInterval:(NSTimeInterval)theSeconds repeats:(BOOL)repeats actions:(VoidBlock)actions;
@end

#import "NSTimer+Additions.h"

static VoidBlock _voidBlock;

@interface NSTimer (AdditionsPrivate) // Private stuff
- (void)theBlock;
@end


@implementation NSTimer (NSTimer_Additions)


+ (NSTimer *)scheduleTimerWithTimeInterval:(NSTimeInterval)theSeconds repeats:(BOOL)repeats actions:(VoidBlock)actions {

 [_voidBlock release];
 _voidBlock = [actions copy];

 NSTimer* timer = [[NSTimer alloc] initWithFireDate:[NSDate date] 
 interval:theSeconds
 target:self 
 selector:@selector(theBlock) 
 userInfo:nil 
 repeats:repeats];
 [timer fire];
 
 return [timer autorelease];
}


- (void)theBlock {
 _voidBlock();
}
 
@end

@interface NSTimer (AdditionsPrivate) // Private stuff 
- (void)theBlock:(VoidBlock)voidBlock;
@end


@implementation NSTimer (NSTimer_Additions)

+ (NSTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)theSeconds repeats:(BOOL)repeats actions:(VoidBlock)actions {
 NSInvocation * invocation = [NSInvocation invocationWithMethodSignature:[self instanceMethodSignatureForSelector:@selector(theBlock:)]];
 NSTimer * timer = [NSTimer scheduledTimerWithTimeInterval:theSeconds
 invocation:invocation
 repeats:repeats];
 [invocation setTarget:timer];
 [invocation setSelector:@selector(theBlock:) ];

 Block_copy(actions);
 [invocation setArg ument:&actions atIndex:2];
 Block_release(actions);

 return timer;
}


- (void)theBlock :(VoidBlock)voidBlock (
 voidBlock();
)

@end

@implementation NSTimer (NSTimer_Additions)

+ (NSTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)theSeconds repeats:(BOOL)repeats actions:(VoidBlock)actions {
 NSInvocation * invocation = [NSInvocation invocationWithMethodSignature:[self instanceMethodSignatureForSelector:@selector(theBlock)]];
 NSTimer * timer = [NSTimer scheduledTimerWithTimeInterval:theSeconds
 invocation:invocation
 repeats:repeats];
 [invocation setTarget:timer];
 [invocation setSelector:@selector(theBlock)];

 objc_setAssociatedObject(timer, @"Block", actions, OBJC_ASSOCIATION_COPY);

 return timer;
}


- (void)theBlock {
 VoidBlock _voidBlock = (VoidBlock)objc_getAssociatedObject(self, @"Block");
 _voidBlock();
}

@end

< /p>

I am very new to blocks and objective-c, I am trying to write my first category using both. My idea is to create a category on NSTimer, which will receive a block as a parameter, this block Will be used for selector calls. Now I have this.

// NSTimer+Additions.h

#import 

typedef void (^VoidBlock)();

@interface NSTimer (NSTimer_Additions)


+ (NSTimer * )scheduleTimerWithTimeInterval:(NSTimeInterval)theSeconds repeats:(BOOL)repeats actions:(VoidBlock)actions;
@end

#import "NSTimer+Additions.h"

static VoidBlock _voidBlock;

@interface NSTimer (AdditionsPrivate) // Private stuff
- (void)theBlock;
@end


@implementation NSTimer (NSTimer_Additions)


+ (NSTimer *)scheduleTimerWith TimeInterval:(NSTimeInterval)theSeconds repeats:(BOOL)repeats actions:(VoidBlock)actions {

 [_voidBlock release];
 _voidBlock = [actions copy];

 NSTimer* timer = [[NSTimer alloc] initWithFireDate:[NSDate date] 
 interval:theSeconds
 target:self 
 selector:@selector(theBlock) 
 userInfo:nil 
 repeats:repeats];
 [timer fire];

 return [timer autorelease];
}


- (void )theBlock {
 _voidBlock();
}

@end

Code points: https://gist.github.com/1065235

Everything compiles well but I have the following error:

2011-07-05 14:35:47.068 TesteTimer [37716:903] *The application was terminated due to an uncaught exception’NSInvalidArgumentException’, Reason:'[NSTimer theBlock]: Unrecognized selector sent to class 0x7fff70bb0a18′

How do I make this class work?

In addition to the wrong goal, your main flaw is that you use static variables. Except for a timer, you will not be able to support it.

Use block as the parameter of the called method.

@interface NSTimer (AdditionsPrivate) // Private stuff
- (void)theBlock:(VoidBlock )voidBlock;
@end


@implementation NSTimer (NSTimer_Additions)

+ (NSTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)theSeconds repeats:(BOOL )repeats actions:(VoidBlock)actions {
 NSInvocation * invocation = [NSInvocation invocationWithMethodSignature:[self instanceMethodSignatureForSelector:@selector(theBlock:)]];
 NSTimer * timer = [NSTimer scheduledTimerWithTimeInterval:theSeconds
 invocation:invocation
 repeats:repeats];
 [invocation setTarget:timer];
 [invocation setSelector:@selector(theBlock:)];

 Block_copy( actions);
 [invocation setArgument:&actions atIndex:2];
 Block_release(acti ons);

 return timer;
}


- (void)theBlock:(VoidBlock)voidBlock {
 voidBlock(); 
}

@end

The problem with using associative references is leakage, because there is no benefit in releasing blocks.

Early methods use cross-references< /p>

You can use associative references to attach blocks to that particular NSTimer instance.

@implementation NSTimer (NSTimer_Additions)

+ (NSTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)theSeconds repeats:(BOOL)repeats actions:(VoidBlock)actions {
 NSInvocation * invocation = [NSInvocation invocationWithMethodSignature:[self instanceMethodSignatureForSelector:@selector(theBlock) ]];
 NSTimer * timer = [NSTimer scheduledTimerWithTimeInterval:theSeconds
 invocation:invocation
 repeats:repeats];
 [invocation setTarget:timer];
 [invocation setSelector :@selector(theBlock)];

 objc_setAssociatedObject(timer, @"Block", actions, OBJC_A SSOCIATION_COPY);

 return timer;
}


- (void)theBlock {
 VoidBlock _voidBlock = (VoidBlock)objc_getAssociatedObject(self , @"Block");
 _voidBlock();
}

@end