Minecraft handles user input from peripherals such as the keyboard & mouse using key-binds. When you press W your character moves forward, and when you press E your inventory opens. Every keybind can also be configured with the settings menu, so you can make your player move with arrow keys instead of WASD if you so desire.

This tutorial assumes you have the key bindings API, if not add "fabric-key-binding-api-v1": "*" to the "depends" block in your fabric.mod.json file.

Adding a key-bind is easy. You'll need to:

• open or create a Client entrypoint
• create a KeyBinding object
• react to the key being pressed

See here for an updated example.

If you already have a Client entrypoint created and you are familiar with how it works, you can safely proceed to the next section. Otherwise, stick around for a quick overview!

In order to create a Client entrypoint, we'll need to do a couple of different things to let Fabric know that we intend to specify code that only needs to be executed by the physical client side. We'll make a quick example class called ExampleClientEntrypoint, but usually the common practice would be to name the class “YourModName” followed by “Client”, e.g. YoYoDeleriumClient or HappySheepHammocksClient. Let's take a look at the code, and then we'll explain what's happening:

/* package */
/* imports */
 
public class ExampleClientEntrypoint implements ClientModInitializer {
 
    // The KeyBinding declaration and registration are commonly executed here statically
 
    @Override
    public void onInitializeClient() {
 
        // Event registration will be executed inside this method
    }
}

So, what are we doing here? Fabric entrypoints for most use cases are designated by implementing a special interface unique to the side or sides that the code in the entrypoint should be run on. For our Client, we simply have our class implement the ClientModInitializer interface. The interface requires us to @Override a single method, onInitializeClient. It is in this method (and the equivalents from the other entrypoints respectively) that we will often call methods provided by the Fabric API for easily registering and adding some of the objects and behaviors that we may wish to have in our mod. Of course, we'll also need to update our fabric.mod.json to include our newly created entrypoint, so be sure to consult the entrypoints page if you need a refresher on that process.

Declare one of these in an area of your preference:

private static KeyBinding keyBinding;

FabricKeyBinding has a Builder for initialization. It takes in an Identifier, InputUtil.Type, key code, and binding category:

keyBinding = KeyBindingHelper.registerKeyBinding(new KeyBinding(
    "key.examplemod.spook", // The translation key of the keybinding's name
    InputUtil.Type.KEYSYM, // The type of the keybinding, KEYSYM for keyboard, MOUSE for mouse.
    GLFW.GLFW_KEY_R, // The keycode of the key
    "category.examplemod.test" // The translation key of the keybinding's category.
));

Sticky keys can also be created with KeyBindingHelper. In vanilla, the sneak and sprint keys act as sticky keys when they are set to 'Sneak: Toggle' and 'Sprint: Toggle' respectively. If a key binding should always act as a sticky key, then pass () → true as the final parameter.

GLFW.GLFW_KEY_R can be replaced with whatever key you want the binding to default to. The category is related to how the keybinding is grouped in the settings page.

The code here will print “Key 1 was pressed!” ingame. Keep note that this is entirely client-side. To have the server respond to a keybind, you'll need to send a custom packet and have the server handle it separately.

For versions since 1.19:

ClientTickEvents.END_CLIENT_TICK.register(client -> {
    while (keyBinding.wasPressed()) {
	client.player.sendMessage(Text.literal("Key 1 was pressed!"), false);
    }
});

For versions below 1.19:

ClientTickEvents.END_CLIENT_TICK.register(client -> {
    while (keyBinding.wasPressed()) {
	client.player.sendMessage(new LiteralText("Key 1 was pressed!"), false);
    }
});