What's wrong with my code? (obj c tweak development) - ios

Question

So, I'm new to tweak development and obj c and I'm trying to change the style of dock with this code
%hook SBWallpaperEffect
-(void)setStyle: (NSInteger)arg1{
arg1 = 5;
}
%end
But it doesn't work. What am I doing wrong?

Answer 1

OK, I think this is the typical kind of pointer problem many programmers face. You are passing a NSInteger to the function, and arg1 is a copy of the value that is passed in. In other words, no matter how you change arg1 inside the function, the original variable does not change.
To make things more clear, look at the following code snippet:
NSInteger myInteger = 0;
NSInteger arg1;
arg1 = myInteger;
arg1 = 5;
// myInteger is still 0!
Changing arg1 does not change the value of myInteger, and that's what you're doing in your function. The arg1 copies the value of the integer passed in, be set to 5, and then gets released at the end of the function.
Instead, try this:
-(void)setStyle:(NSInteger *)arg1{
arg1 = 5;
}
and then call the function like this:
NSInteger myInteger = 0;
[self setStyle:&myInteger];
//myInteger is now 5!
Now you will get the result you want.
If you don't want to deal with these messy pointer stuff, use the returning value of the function to pass the number like this:
-(NSInteger)getStyle:(NSInteger)arg1{
// do some calculation
arg1 += 5;
return arg1;
}
or something like this (with no parameters):
-(NSInteger)getStyle{
return 5;
}
and call it like:
myInteger = [self getStyle:myInteger];
// or
myInteger = [self getStyle];
Now myInteger will also be 5. Hope this helps :)

Answer 2

Ok so i figured out that im using NSInteger instead of long long. Like this:
(void)setStyle:(long long)arg1;
Also, i was using
SBWallpaperEffect
Instead of
SBWallpaperEffectView
And i should've set the value inside %orig
So, this is the right way to write it:
%hook SBWallpaperEffectView
- (void)setStyle:(long long)arg1{
arg1 = 5;
%orig(arg1);
return;
}
%end