So I want to have a button added in a GUI that is in a base class, that would trigger a method in my mod. It sounded like it would be simple, (because forge API covers almost everything  ) but I discovered only "coremods" can do this. I found only a few posts on this topic and 1 tutorial: http://www.minecraftforge.net/wiki/Using_Access_Transformers but In that tutorial the coremod did not give me an error, but I was not sure what exactly it did  . I downloaded a few examples of coremods, like chickenbonescore and ars magica (I had to decompile it). I was unsuccessful at finding how these worked. Another post on the forums said "only advanced modders who know what they're doing should use this tool" (or something along those lines), but If no one learns it in the first place, they can't become an advanced modder, can't they? Can anyone out there enlighten me on this topic? Not many tutorials show how this work, and I really want to know more about how this works, thanks.

 

 

P.S. Is there a way of doing this so that the regular mod doesn't have to be converted to a core mod, just have the core mod trigger a method in the regular mod? (eg. ars magica uses 2 mods, a core and a regular, since converting the regular to the core might be difficult) Oh yea, and if you could explain it rather than redirecting me too an api doc that would be nice!

Thank you so much! Ok, so I don't need any of this core mod stuff! Awesome! Thanks a lot.

I just tried to do the part where i add a button, I don't know to much about java reflection so I probably made many boo boos! it does print "tick" on my screen when I open the book though, (YAY!)

	
        @Override
public void tickStart(EnumSet<TickType> type, Object... tickData) {
	if (Minecraft.getMinecraft().currentScreen instanceof GuiScreenBook) {
		Minecraft.getMinecraft().thePlayer.addChatMessage("tick");
		try {
			Class<?> c = Minecraft.getMinecraft().currentScreen.getClass();
			Field f = c.getDeclaredField("controlList");
			f.set(Minecraft.getMinecraft().currentScreen, new GuiButton(3,
					Minecraft.getMinecraft().currentScreen.width / 2 + 104,
					4 + Minecraft.getMinecraft().currentScreen.height, 98,
					20, StatCollector.translateToLocal("book.signButton")));
		} catch (NoSuchFieldException e) {
			e.printStackTrace();
		} catch (SecurityException e) {
			e.printStackTrace();
		} catch (IllegalArgumentException e) {
			e.printStackTrace();
		} catch (IllegalAccessException e) {
			e.printStackTrace();
		}
	}

Do I need to read the GuiScreenBook 's width and height? or can I use Minecrafts Gui height and width

P.S. it gives me an error at Field f = c.getDeclaredField("controlList");

 

or u can just close that screen, using the void onClose(or something)and open the new gui.

I think thats a good temporary solution, but if you have any Idea of how to use java reflection like this, plz tell me!

	
        @Override
public void tickStart(EnumSet<TickType> type, Object... tickData) {
	if (Minecraft.getMinecraft().currentScreen instanceof GuiScreenBook) {
		Minecraft.getMinecraft().thePlayer.addChatMessage("tick");
		try {
			Class<?> c = Minecraft.getMinecraft().currentScreen.getClass();
			Field f = c.getDeclaredField("controlList");
			f.set(Minecraft.getMinecraft().currentScreen, new GuiButton(3,
					Minecraft.getMinecraft().currentScreen.width / 2 + 104,
					4 + Minecraft.getMinecraft().currentScreen.height, 98,
					20, StatCollector.translateToLocal("book.signButton")));
		} catch...{
			e.printStackTrace();
		}
	}

I don't have much experience with reflection so it may not be entrirely true what I'm writing. Using relection is not cheap, it doesn't seem right to me to do in every tick when GUI is open. Also you're in every tick creating a new button? And with that button you are rewriting collection with GUI elements? I might be reading it wrong though...