Paged GUI

A paged GUI is a gui that can display pages of either Items or GUIs.

Control Items

First, we'll need to create the page switching buttons.
This is an example for a "Page Back" Item:

KotlinJava

class BackItem : PageItem(false) {

    override fun getItemProvider(gui: PagedGUI): ItemProvider {
        val builder = ItemBuilder(Material.RED_STAINED_GLASS_PANE)
        builder.setDisplayName("§7Previous page")
            .addLoreLines(
                if (gui.hasPageBefore())
                    "§7Go to page §e" + gui.currentPageIndex + "§7/§e" + gui.pageAmount 
                else "§cYou can't go further back"
            )
        return builder
    }

}

public class BackItem extends PageItem {

    public BackItem() {
        super(false);
    }

    @Override
    public ItemProvider getItemProvider(PagedGUI gui) {
        ItemBuilder builder = new ItemBuilder(Material.RED_STAINED_GLASS_PANE);
        builder.setDisplayName("§7Previous page")
            .addLoreLines(gui.hasPageBefore()
                ? "§7Go to page §e" + gui.getCurrentPageIndex() + "§7/§e" + gui.getPageAmount()
                : "§cYou can't go further back");

        return builder;
    }

}

This is an example for a "Page Forward" Item:

KotlinJava

class ForwardItem : PageItem(true) {

    override fun getItemProvider(gui: PagedGUI): ItemProvider {
        val builder = ItemBuilder(Material.GREEN_STAINED_GLASS_PANE)
        builder.setDisplayName("§7Next page")
            .addLoreLines(
                if (gui.hasNextPage())
                    "§7Go to page §e" + (gui.currentPageIndex + 2) + "§7/§e" + gui.pageAmount 
                else "§cThere are no more pages"
            )
        return builder
    }

}

public class ForwardItem extends PageItem {

    public ForwardItem() {
        super(true);
    }

    @Override
    public ItemProvider getItemProvider(PagedGUI gui) {
        ItemBuilder builder = new ItemBuilder(Material.GREEN_STAINED_GLASS_PANE);
        builder.setDisplayName("§7Next page")
            .addLoreLines(gui.hasNextPage()
                ? "§7Go to page §e" + (gui.getCurrentPageIndex() + 2) + "§7/§e" + gui.getPageAmount()
                : "§cThere are no more pages");

        return builder;
    }

}

More information about ControlItems in the Items section.

Info

You also might want to register these Items as global ingredients.

Creating the GUI

Paged Items

Now that we've created the ControlItems, let's make the actual GUI:

KotlinJava

val border = SimpleItem(ItemBuilder(Material.BLACK_STAINED_GLASS_PANE).setDisplayName("§r"))

// an example list of items to display
val items = Material.values()
    .filter { !it.isAir && it.isItem }
    .map { SimpleItem(ItemBuilder(it)) }

// create the gui
val gui = GUIBuilder(GUIType.PAGED_ITEMS)
    .setStructure(
        "# # # # # # # # #",
        "# x x x x x x x #",
        "# x x x x x x x #",
        "# # # < # > # # #")
    .addIngredient('x', Markers.ITEM_LIST_SLOT_HORIZONTAL) // where paged items should be put
    .addIngredient('#', border)
    .addIngredient('<', BackItem())
    .addIngredient('>', ForwardItem())
    .setItems(items)
    .build()

Item border = new SimpleItem(new ItemBuilder(Material.BLACK_STAINED_GLASS_PANE).setDisplayName("§r"));

// an example list of items to display
List<Item> items = Arrays.stream(Material.values())
    .filter(material -> !material.isAir() && material.isItem())
    .map(material -> new SimpleItem(new ItemBuilder(material)))
    .collect(Collectors.toList());

// create the gui
GUI gui = new GUIBuilder<>(GUIType.PAGED_ITEMS)
    .setStructure(
        "# # # # # # # # #",
        "# x x x x x x x #",
        "# x x x x x x x #",
        "# # # < # > # # #")
    .addIngredient('x', Markers.ITEM_LIST_SLOT_HORIZONTAL) // where paged items should be put
    .addIngredient('#', border)
    .addIngredient('<', new BackItem())
    .addIngredient('>', new ForwardItem())
    .setItems(items)
    .build();

In-game, it will look like this:

Paged GUIs

Instead of using Items, you can also use whole GUIs as pages. In the following example I used two slightly different versions of the GUI created above and added them as pages. Now I can switch between two paged GUIs.

KotlinJava

val gui = GUIBuilder(GUIType.PAGED_GUIs)
    .setStructure(
        "x x x x x x x x x",
        "x x x x x x x x x",
        "x x x x x x x x x",
        "x x x x x x x x x",
        ". . < . . . > . .")
    .addIngredient('x', Markers.ITEM_LIST_SLOT_HORIZONTAL) // where paged items should be put (in this case: the parts of the nested GUI)
    .addIngredient('<', BackItem())
    .addIngredient('>', ForwardItem())
    .setGUIs(listOf(page1GUI, page2GUI))
    .build()

// show the window
SimpleWindow(player, "InvUI", gui).show()

GUI gui = new GUIBuilder<>(GUIType.PAGED_GUIs)
    .setStructure(
        "x x x x x x x x x",
        "x x x x x x x x x",
        "x x x x x x x x x",
        "x x x x x x x x x",
        ". . < . . . > . .")
    .addIngredient('x', Markers.ITEM_LIST_SLOT_HORIZONTAL) // where paged items should be put (in this case: the parts of the nested GUI)
    .addIngredient('<', new BackItem())
    .addIngredient('>', new ForwardItem())
    .setGUIs(Arrays.asList(page1GUI, page2GUI))
    .build();

// show the window
new SimpleWindow(player, "InvUI", gui).show();

In-game it looks like this: