How to access GUI from sponge, want to create a marketplace / auction house like this: https://dev.bukkit.org/projects/global-market
When you say GUI I think you mean an Inventory Interface.
You can create custom inventories, first check out the base Inventory API
https://github.com/SpongePowered/SpongeAPI/blob/bleeding/src/main/java/org/spongepowered/api/item/inventory/Inventory.java
There isn’t any documentation on creating inventories currently, however there are many threads on the forums and you may find code from other plugins helpful too.
This may be a bit too advanced for me heh xD – Do you know if Forge would be easier to work with for a server-wide player run open market? I desperately want a GUI as browsing is a huge ++ to markets, but if it could use Minecraft’s built-in gui’s would be better, do you know of any examples of this being implemented?
Would forge gui creating be easier to the point I should just do it there instead regardless?
Ideally I want the closest to this with the least work as possible: Items Pricing Marketplace(as of now 10/20/2016) - YouTube
If you don’t mind the limitations of using vanilla chest interfaces and the like, it’s possible with sponge
There’s this WIP plugin by @Socratic_Phoenix that may be what you’re looking for