Trying to compile MobileSubstrate addon - Undefined symbol

Question

Hi!

I went through this tutorial to create a MobileSubstrate addon. I could compile the example hook without errors.

But as soon as I add

#import <SpringBoard/SBAwayController.h>

in ExampleHookProtocol.h and

SBAwayController *awayController = [SBAwayController sharedAwayController];

in ExampleHookLibrary.mm (as the first line of the __$ExampleHook_AppIcon_Launch function) I get the following error message when attempting to make (triggered by the latter change):

Undefined symbols:
  "_OBJC_CLASS_$_SBAwayController", referenced from:
    __objc_classrefs__DATA@0 in ExampleHookLibrary.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
make: *** [ExampleHook.dylib] Error 1.

The header file for SBAwayController is located in /var/toolchain/sys30/usr/include/SpringBoard, just like SBApplicationIcon.h, which is used by the ExampleHook.

I'm compiling on my iPod touch 2G.

Can anyone help me?

Thanks in advance,

Eric

Answer 1

Since there is nothing to link to when you compile, you need to get the class at runtime, so add

Class $SBAwayController = objc_getClass("SBAwayController");

in the initializer, and change

SBAwayController *awayController = [SBAwayController sharedAwayController];

to

SBAwayController *awayController = [$SBAwayController sharedAwayController];