Question

What is the appropriate way to call a method with an action, and what should the method itself look like for passing a CGPoint parameter? I’ve tried to look up examples online without much luck, so I’ve been pretty much guessing.

What I have tried is this for calling it:

    CGPoint spriteCoord = saveStation.sprite.position;

    id a1=[CCMoveTo actionWithDuration:.4 position:ccp(saveStation.sprite.position.x,saveStation.sprite.position.y)];
    id actionSaveStationReaction = [CCCallFuncND actionWithTarget:self selector:@selector(saveStationReaction : data:) data:&spriteCoord];

    [hero.heroSprite runAction:[CCSequence actions:a1, actionSaveStationReaction, nil]];

And the method itself:

-(void) saveStationReaction:(id)sender data:(void *)data {

    CGPoint spriteCoord = (void *)data; //error: Invalid initializer 

    NSLog(@"spriteCoord x = %f", spriteCoord.x);
    NSLog(@"spriteCoord y = %f", spriteCoord.y);

}

Answer 1

The proper way to send a CGPoint (or any non-id type like C structs) to a method that takes an id as parameter (any method that uses performSelector) is by wrapping it in an NSValue object:

NSValue* value = [NSValue valueWithBytes:&spriteCoord objCType:@encode(CGPoint)];

In the method that is being called you can retrieve the point from the NSValue object by casting the data pointer to NSValue* and calling getValue:

-(void) saveStationReaction:(id)sender data:(void *)data {

    CGPoint spriteCoord;
    [((NSValue*)data) getValue:&spriteCoord];

    NSLog(@"spriteCoord x = %f", spriteCoord.x);
    NSLog(@"spriteCoord y = %f", spriteCoord.y);

}