New Input System overview in Unity - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Input Action callback?

Consider this Unity C# code snippet using the New Input System:

using UnityEngine;
using UnityEngine.InputSystem;

public class PlayerController : MonoBehaviour
{
    public InputAction jumpAction;

    void OnEnable()
    {
        jumpAction.Enable();
        jumpAction.performed += ctx => Debug.Log($"Jump performed at {ctx.time}");
    }

    void OnDisable()
    {
        jumpAction.Disable();
    }
}

If the player presses the jump button at game time 5.2 seconds, what will be printed?

Unity

using UnityEngine;
using UnityEngine.InputSystem;

public class PlayerController : MonoBehaviour
{
    public InputAction jumpAction;

    void OnEnable()
    {
        jumpAction.Enable();
        jumpAction.performed += ctx => Debug.Log($"Jump performed at {ctx.time}");
    }

    void OnDisable()
    {
        jumpAction.Disable();
    }
}

A No output because jumpAction is not enabled

B Jump performed at 0

C Jump performed at ctx.time

D Jump performed at 5.2

💡 Hint

Look at the ctx.time property in the callback. It gives the time of the input event.

The performed callback runs when the jump button is pressed. The ctx.time holds the game time when the input happened, here 5.2 seconds, so the output is exactly "Jump performed at 5.2".

🧠 Conceptual

intermediate

Which Input System component stores the player's input bindings?

In Unity's New Input System, where are the player's input bindings (like keyboard keys or gamepad buttons) stored?

A InputUser

B InputActionAsset

C InputControlScheme

D InputActionMap

💡 Hint

Think about the asset that holds all actions and their bindings.

The InputActionAsset is the main container that stores all input actions and their bindings. It can contain multiple InputActionMaps, but the bindings are defined in the asset.

❓ Predict Output

advanced

What is the output of this InputAction value reading?

Given this code snippet:

var moveAction = new InputAction(type: InputActionType.Value, binding: "/leftStick");
moveAction.Enable();
var value = moveAction.ReadValue<Vector2>();
Debug.Log(value);

If the left stick is centered (not moved), what will be printed?

Unity

var moveAction = new InputAction(type: InputActionType.Value, binding: "<Gamepad>/leftStick");
moveAction.Enable();
var value = moveAction.ReadValue<Vector2>();
Debug.Log(value);

A (0.0, 0.0)

B (1.0, 1.0)

C (0.5, 0.5)

D NullReferenceException

💡 Hint

Think about the default position of a gamepad's left stick when untouched.

The left stick centered means no input, so the vector value is (0,0). The ReadValue<Vector2>() returns this neutral position.

🔧 Debug

advanced

Why does this InputAction callback never run?

Look at this code:

public InputAction fireAction;

void Start()
{
    fireAction.performed += ctx => Debug.Log("Fire!");
}

void Update()
{
    if (fireAction.triggered)
        Debug.Log("Triggered");
}

Why does pressing the fire button never print "Fire!"?

Unity

public InputAction fireAction;

void Start()
{
    fireAction.performed += ctx => Debug.Log("Fire!");
}

void Update()
{
    if (fireAction.triggered)
        Debug.Log("Triggered");
}

A The performed event only fires in Update, not Start

B The lambda syntax is incorrect

C fireAction is never enabled, so callbacks don't run

D triggered is false because fireAction is disabled

💡 Hint

Check if the InputAction is enabled before use.

InputActions must be enabled to listen for input and trigger callbacks. Since fireAction.Enable() is missing, the performed event never fires.

🧠 Conceptual

expert

Which feature allows multiple players to use separate input devices simultaneously?

In Unity's New Input System, what feature lets you manage multiple players each with their own input devices, so they don't interfere with each other?

A InputUser

B InputBindingMask

C InputActionMap

D InputControlScheme

💡 Hint

Think about the system that tracks users and their devices.

InputUser is the feature designed to handle multiple players by associating input devices with users, allowing separate input contexts for each player.