CMSignals

Qt Signals and Slots clone to Objective-c

Example

A class with a signal.

#import <Foundation/Foundation.h>
#import "NSObject+CMSignals.h"
@protocol CMExampleSignals

CM_signals

    - (void)signalMethod:(NSString *)string andNumber:(NSNumber *)number;

@end

@interface CMExample : NSObject <CMExampleSignals>

@end

A class with a slot

#import <Foundation/Foundation.h>
#import "NSObject+CMSignals.h"

@class CMExample;

@interface CMExampleReceiver : NSObject
- (id)initWithExample:(CMExample *)example;

- (void)slotMethod:(NSString *)string andNumber:(NSNumber *)number;

@end

#import "CMExampleReceiver.h"

@implementation CMExampleReceiver

- (id)initWithExample:(CMExample *)example
{
    self = [super init];
    
    if (self) {
        [self connect:@selector(signalMethod:andNumber:)
                    from:example
                    with:@selector(slotMethod:andNumber:)];
    }
    
    return self;
}


- (void)slotMethod:(NSString *)string andNumber:(NSNumber *)number
{
    NSLog(@"Slot called: %@ - %@", [number description], string);
}


@end

Somewhere on CMExample we execute:

 [self emit:@selector(signalMethod:andNumber:) withArguments:@[ @"Codeminer", [NSNumber numberWithInt:42]]];

And we get the slotMethod called.

Note that one can use the category on NSObject or use the singleton class CMSignals to connect, disconnect and emit signals/slots

Why not NSNotificationCenter?

• Signal is a method definition;
• Slot is a method;
• No NSNotification treatment;
• No userInfo dictionary;
• Classes describe a well defined signal protocol.

CMSignals actually use NSNotificationCenter under the hood. CMSignals remove the boilerplate.

TODO

• [ ] Send broadcast signals using a class instead of an object;
• [✓] Make it a CocoaPod.

Credits

CMSignals was created by Eduardo Gurgel and Tiago Bastos.

Many thanks to Codeminer 42.