Communication between objects - C4Framework

Question

I'm working with the alpha release of C4 and I'm trying to send messages between objects but i cant make it work. Im trying with a really simple example but i cant make it work... I've tried this:

[ashape listenFor:@"touch" from:anothershape andRunMethod:@"receive"];

but I dont get any messages or nothing...

this is what i have:

#import "MyShape.h"

@implementation MyShape
-(void)receive {
    C4Log(@"this button");
}
@end

Hey david, 2 questions before I answer: (1) are "ashape" and "anothershape" both objects of the class MyShape? (2) are you trying to make one of the objects react when the other is first touched using the touchesBegan method? — C4 - Travis, Apr 23 '12 at 17:04
1) Yes 2) Yes. For example: if i have to squares, i want to change the color of the second square when i press on the first one and viceversa. — davidpenuela, Apr 24 '12 at 21:35

score 1 · Accepted Answer · answered Apr 24 '12 at 21:51

I see one main problem with the code you posted.

By default, all visible objects in C4 post a touchesBegan notification when they are tapped. In your code you are listening for @"touch" whereas @"touchesBegan" is what you should be listening for.

The changing color method is easy to implement... In your MyShape.m file, you can use a method like:

-(void)changeColor {
    CGFloat red = RGBToFloat([C4Math randomInt:255]);
    CGFloat green = RGBToFloat([C4Math randomInt:255]);
    CGFloat blue = RGBToFloat([C4Math randomInt:255]);

    self.fillColor = [UIColor colorWithRed:red green:green blue:blue alpha:1.0f];
}

In order to get things working nicely, your C4WorkSpace.m should look like:

#import "C4WorkSpace.h"
#import "MyShape.h"

@implementation C4WorkSpace {
    MyShape *s1, *s2;
}

-(void)setup {
    s1 = [MyShape new];
    s2 = [MyShape new];

    [s1 rect:CGRectMake(100, 100, 100, 100)];
    [s2 rect:CGRectMake(300, 100, 100, 100)];

    [s1 listenFor:@"touchesBegan" fromObject:s2 andRunMethod:@"changeColor"];
    [s2 listenFor:@"touchesBegan" fromObject:s1 andRunMethod:@"changeColor"];

    [self.canvas addShape:s1];
    [self.canvas addShape:s2];
}
@end

Communication between objects - C4Framework

1 Answers1