hooks.md

Hooks In Practice

So, we are ready to start making our tweak.

Sure we know what hooks are and how to properly syntax them but now its time too use them in practise

Lets load up Tweak.x in our IDE of choice and remove the existing code in there as we wont need any of it.

As you will remember a hook looks like this

%hook randomClass
-(void)aRandomMethod {
  %orig;
  // our modified code here
}
%end

The %orig doesn't always need to come after the method but in this guide for simplicity we shall use it

We now need to find a class to hook into and modify one of the methods

We can do this using Limneos's Headers This link will become very important as it is essentially our Wikipedia we can refer too at any time.

Our classes are stored in header files, each one of apples frameworks have several header files, because there are thousands of classes we use this site to sort through them.

One of the trickiest parts about Tweak Development is finding the right header and the right classes to accomplish the specific task

In this Example Tweak we will be creating a Tweak that provides haptic feedback to the user, so lets go and try and find the right header that will contain a class that we can use to create our tweak.

Lets break it down a bit, into a small chart so we can understand what we want our tweak to do.

I shall write our tweak breakdown in pseudocode this basically means it is not real code but is easy to translate.

if(VolumeButtonIsPressed) {
  PlayHapticFeedback
}

Now lets convert that pseudocode into something that looks more like obj-c

#import <ourHeaderThatControlsVolume.h>
%hook classThatControlsVolumeFromOurHeader
-(void)ourMethodThatHappensWhenVolumeButtonIsPressed {
  %orig;
  PlayHapticFeedback;
}

Please not the above code DOES NOT WORK it is just a simple breakdown so you understand a little better

Finding The Right Header

When we get onto Limneos's Headers We will see a few things, on the main homepage we will see a massive list of frameworks. We will want to click on SpringBoard as that is the framework we will be using during this example.

Now we are in the SpringBoard folder, this contains all the header files for the SpringBoard.

We are going to want to search the list that is in front of us for Volume

SBVolumeControl.h   
SBVolumeControlState.h   
SBVolumeHUDDomain.h   
SBVolumeHUDSettings.h   
SBVolumeHUDViewController.h   
SBVolumeHUDViewControllerDelegate.h   
SBVolumeHardwareButton.h   
SBVolumeHardwareButtonActions.h   
SBVolumePressBandit.h

Note they are all stored in Alphabetical Order

Your next question is, well how do you what is the right one. Luckily of us Apple names all of there headers in accordance to what they do.

Note most headers relating to the SpringBoard usually start with 'SB'

So using common sense, we want to find a header that contains the methods for Volume Control.

Our best guess it is SBVolumeControl.h

We have now found our header so we can now learn a bit more about headers