How to make a already existing minecraft button open a screen that's different from what it usually opens

[shushi93]

Description

In Options>Resource Packs, it normally opens the PackSelectionScreen
However, I want it to open my own screen (e.g. ExampleScreen)
Mod Menu uses ModifyArg, but I don't understand it

@Mixin(TitleScreen.class)
public class MixinTitleScreen {
	@ModifyArg(at = @At(value = "INVOKE", target = "Lnet/minecraft/client/realms/gui/screen/RealmsNotificationsScreen;init(Lnet/minecraft/client/MinecraftClient;II)V"), method = "init", index = 2)
	private int adjustRealmsHeight(int height) {
		if (ModMenuConfig.MODIFY_TITLE_SCREEN.getValue() && ModMenuConfig.MODS_BUTTON_STYLE.getValue() == ModMenuConfig.TitleMenuButtonStyle.CLASSIC) {
			return height - 51;
		} else if (ModMenuConfig.MODS_BUTTON_STYLE.getValue() == ModMenuConfig.TitleMenuButtonStyle.REPLACE_REALMS || ModMenuConfig.MODS_BUTTON_STYLE.getValue() == ModMenuConfig.TitleMenuButtonStyle.SHRINK) {
			return -99999;
		} else {
			return height;
		}
	}

	@ModifyArg(method = "render", at = @At(value = "INVOKE", target = "Lnet/minecraft/client/gui/DrawContext;drawTextWithShadow(Lnet/minecraft/client/font/TextRenderer;Ljava/lang/String;III)V", ordinal = 0))
	private String onRender(String string) {
		if (ModMenuConfig.MODIFY_TITLE_SCREEN.getValue() && ModMenuConfig.MOD_COUNT_LOCATION.getValue().isOnTitleScreen()) {
			String count = ModMenu.getDisplayedModCount();
			String specificKey = "modmenu.mods." + count;
			String replacementKey = I18n.hasTranslation(specificKey) ? specificKey : "modmenu.mods.n";
			if (ModMenuConfig.EASTER_EGGS.getValue() && I18n.hasTranslation(specificKey + ".secret")) {
				replacementKey = specificKey + ".secret";
			}

			return string.replace(I18n.translate(I18n.translate("menu.modded")), I18n.translate(replacementKey, count));
		} else {
			return string;
		}
	}
}

Mod menu replaces the realms button to open the mods screen, but I can't figure out what it's doing exactly to re-implement it to what I need to do.
Currently, I have another button on the TitleScreen, that opens this custom screen, but I want to open the custom screen when the resource pack button is clicked.

I do not wish to completely override the PackSelectionScreen, so that I can make it so that if there are any critical errors in the opening of my screen, it falls back to the PackSelectionScreen
Edit: I'm trying Inject. I don't know if ModifyArg was made for this type of stuff
Edit: I managed to inject into

@Inject(at = @At(value = "RETURN", target = "Lnet/minecraft/client/gui/layouts/GridLayout;createRowHelper(I)Lnet/minecraft/client/gui/layouts/GridLayout$RowHelper;"), method = "init") 

I want to modify this code from OptionsScreen.java

rowHelper.addChild(
			this.openScreenButton(
				RESOURCEPACK,
				() -> new PackSelectionScreen( //modify this to open my custom screen (ExampleScreen) instead
					this.minecraft.getResourcePackRepository(), this::applyPacks, this.minecraft.getResourcePackDirectory(), Component.translatable("resourcePack.title")
				)
			)
		);

I want to change it from PackSelectionScreen to ExampleScreen
I tried using RETURN, and copy pasted the code, and then added all missing local variables, but i eventually got to a local varaible I just cldnt add (i cldn't find it)

Edit: I got to here

@ModifyArg(method = "init", at = @At(value = "INVOKE", target = "Lnet/minecraft/client/gui/layouts/GridLayout$RowHelper;addChild(Lnet/minecraft/client/gui/layouts/LayoutElement;)Lnet/minecraft/client/gui/layouts/LayoutElement;"), index = 5)

I just put a random index number, because I cldn't figure out from here how to proceed

Edit:

So,

The one currently outlined in white is the original one, which opens the pack selection screen
All others duplicates open my screen

@Mixin(OptionsScreen.class)
public abstract class ResourceScreenMixin extends Screen {

    @Shadow
    @Final
    private static Component RESOURCEPACK;

    protected ResourceScreenMixin(Component component) {
        super(component);
    }

    @Inject(method = "init", at = @At(value = "INVOKE", target = "Lnet/minecraft/client/gui/layouts/GridLayout$RowHelper;addChild(Lnet/minecraft/client/gui/layouts/LayoutElement;)Lnet/minecraft/client/gui/layouts/LayoutElement;"), locals = LocalCapture.CAPTURE_FAILEXCEPTION)
    private void packButton(CallbackInfo ci, LinearLayout linearLayout, LinearLayout linearLayout2, GridLayout gridLayout, GridLayout.RowHelper rowHelper) {
        rowHelper.addChild(
            this.openScreenButton(
                    RESOURCEPACK,
                    () -> new ExampleScreen(new ExampleGui())
            )
        );
    }

    @Overwrite
    private Button openScreenButton(Component component, Supplier<Screen> supplier){
        return Button.builder(component, button -> Minecraft.getInstance().setScreen((Screen)supplier.get())).build();
    }
}

@Overwrite

makes it not throw an error, but clearly my code is wrong
I have no idea what i did, but i did something

Yet another edit

rowHelper.addChild(
			this.openScreenButton(
				RESOURCEPACK,
				() -> new PackSelectionScreen(
					this.minecraft.getResourcePackRepository(), this::applyPacks, this.minecraft.getResourcePackDirectory(), Component.translatable("resourcePack.title")
				)
			)
		);

I hooked onto this using:

@ModifyArg(method = "init", at = @At(value = "INVOKE", target = "Lnet/minecraft/client/gui/screens/options/OptionsScreen;rowHelper.addChild()V"), index = 14)

I got to here
I want to change the parameters of of it so that instead of

() -> new PackSelectionScreen( ...

its

() -> new ExampleScreen(ExampleGui() ...

[shushi93]

So I found a solution to this,
by following this: https://github.com/LlamaLad7/MixinExtras/wiki/Expressions
you can make an expression to hook onto,

this.openScreenButton(RESOURCEPACK, ?)

then, use ModifyArg with index of 1 to change the supplier value to your own screen
full code:

@Definition(id = "openScreenButton", method = "Lnet/minecraft/client/gui/screens/options/OptionsScreen;openScreenButton(Lnet/minecraft/network/chat/Component;Ljava/util/function/Supplier;)Lnet/minecraft/client/gui/components/Button;")
    @Definition(id = "RESOURCEPACK", field = "Lnet/minecraft/client/gui/screens/options/OptionsScreen;RESOURCEPACK:Lnet/minecraft/network/chat/Component;")
    @Expression("this.openScreenButton(RESOURCEPACK, ?)")
    @ModifyArg(method = "init", at = @At("MIXINEXTRAS:EXPRESSION"), index = 1)
    private Supplier<Screen> redirectButton(Supplier supplier){
        supplier = () -> new ExampleScreen(new ExampleGui());
        return supplier;
    }

(I believe this is the correct and working code)
I have not yet put the other parameters that the old Pack selection screen takes, e.g.

this.minecraft.getResourcePackRepository(), ...

But for now, this works