A Step-by-Step Approach to Crafting Reusable UI in Unity

Introduction

In Unity projects, be it games, applications, or interactive websites, the user interface (UI) is a pivotal factor in user engagement. Achieving a consistent and visually appealing UI across large projects poses challenges, but the solution lies in leveraging reusable UI components.

This blog will explore reusable UI elements, providing a step-by-step guide to streamline your Unity development process. Join us as we delve into the practicalities of creating a scalable, consistent, and visually pleasing UI that enhances user experiences across Unity projects.

Step 1: Identify the common user interface elements

You must first identify the common UI elements that will be frequently used in the project, including buttons, text, menu screens, backdrop, holders, sliders and more. Identify which component should be standardized and reused.

Step 2: Create prefabs

After the identification of reusing components, you can implement the design accordingly that suits most cases. Prefabs are created in generalized form so that the components can be reused in multiple places in different scenes, too. Prefabs serve as a template in unity, allowing it to be instantiated or used wherever we want.

Step 3: User Interface Asset Library

You can create a library of UI assets, such as prefabs, that can be easily imported throughout the project. As such, you can create materials, textures, and fonts which bring a consistent look. For instance, saving a bold font with an underlay effect and using title text everywhere within the project maintains uniformity.

Step 4: Develop Custom Scripts

When your UI components need specific, adaptable behaviour and interactions, it's essential to design scripts that offer maximum flexibility and configurability. These scripts can be attached to the prefabs to define their unique functionality and logic. For instance, you can create a scriptable object to add audio when clicking a button.

Step 5: Arrange asset folders

You can establish folders to house UI components like panels, scripts(managers, controllers) and more, as an effective organization helps track what you want. For instance, a button folder that includes the prefab of different buttons used in the project can be created.

Step 6: Establish naming conventions and patterns

Implement a consistent naming convention for related assets and UI components, making finding and utilising these elements for you and your team easier. For instance, you might use a naming convention like CTA-Button-Green to prefab a green button and reuse the same button, changing the colours where required.

Step 7: Verify Component Functionality

Before putting the components back into use, it's essential to thoroughly test their performance to ensure they function effectively. All necessary improvements must be made during this testing phase.

Step 8: Reuse

With tested and refined prefabs, you can easily incorporate them into your scenes using simple drag-and-drop actions. Make the necessary adjustments to fit the specific interface requirements of your project.

Step 9: Customize and continue

Utilize the prefab as a starting point and apply the required changes. You can unpack the prefab if these changes are specific to a particular scene. However, be careful, as you must not unpack the prefab completely. Rather, pack it and modify it accordingly.

While prefabs are fundamental to reusability, a more comprehensive approach involves creating modular, flexible, and maintainable UI components. Here are some additional concepts and strategies to consider when working with reusable UI components in Unity:

Model-View-ViewModel(MVVM) Pattern:

It is a useful pattern for building and establishing UI components in Unity. It involves a clear separation of concerns: the UI (View), the application logic (ViewModel), and the associated data (Model). Here, the View is dedicated to presenting the UI elements, while the ViewModel encapsulates the logic and state of the UI component, and the Model houses the data the UI interacts with.

This division of responsibilities significantly streamlines the management and maintenance of UI components, fostering improved testability and enhancing their potential for reuse. By separating these elements, developers gain greater control over each component, promoting efficiency, clarity, and reliability in Unity projects.

Decorator Pattern:

Decorator pattern helps to dynamically add or change the behaviour of user interface components. It allows you to improve the appearance or functionality of the user interface without changing its basic structure. Imagine you have a button in your user interface and want to create reusable variations of this button with different styles and behaviours while still keeping the core button intact.

Strategy Pattern:

The Strategy pattern has proven to be very useful in changing the behaviour of many user interface elements. For instance, it can be employed to implement diverse input validation strategies for input fields or distinct display strategies for score displays.

Composite Pattern:

The Composite pattern simplifies the creation of complex UI components by enabling the assembly of simpler elements. For example, it allows you to construct a UI panel containing buttons, labels, and input fields, treating each as a distinct building block. This approach streamlines the organization of detailed UI screens.

Singleton Pattern:

You can use this pattern to employ the UI components that must be accessible from various parts of your application, such as a universal UI manager or input manager. For example, if you require consistent settings or data throughout your entire project, you can implement the Singleton pattern with the "Don't Destroy On Load" functionality in Unity. This pattern guarantees the presence of only a single instance of these components.

Observer Pattern:

You can follow this pattern when you want UI components to react to the changes in data or events. This pattern is useful for ensuring UI elements stay synchronized with the changes in the game state, such as health bars that automatically adjust as a character's health undergoes changes.

Design Patterns:

You can apply design patterns like the singleton and observer patterns to manage UI components, ensuring their interactivity and effectiveness. For instance, UI components can seamlessly adapt to changes in game states or other relevant events. Let's discuss in implementation of this pattern.

Implementation:
UI components can take on the role of Observers by registering to specific events they find relevant, such as alterations in player health, score, or game events. When such events occur, the subject notifies all registered observers, enabling them to promptly update their UI components accordingly.

public class Subject
{
  private List<Observer> observers = new List<Observer>();
  public void RegisterObserver(Observer observer)
  {
    observers.Add(observer);
  }

  public void UnregisterObserver(Observer observer)
  {
    observers.Remove(observer);
  }

  public void NotifyObservers(EventData eventData)
  {
    foreach (Observer observer in observers)
    {
        observer.UpdateUI(eventData);
    }
  }
}

The Subject class takes on the role of managing a collection of observers and subsequently notifying them of the occurrence of specific events. This collection is kept private, and stores references to instances of the Observer class. These observers represent the UI components seeking to respond to particular events.

public class Observer : MonoBehaviour
{
  public void OnEnable()
  {
    // Register this UI component as an observer
    SubjectManager.Instance.RegisterObserver(this);
  }
  
  public void OnDisable()
  {
      // Unregister this UI component when it's disabled
      SubjectManager.Instance.UnregisterObserver(this);
  }
  
  public void UpdateUI(EventData eventData)
  {
      // Update UI based on the event data
  }
}

The Observer class incorporates a UI element, such as a health bar or score display, that responds to particular events or alterations in the game or application. UI components, functioning as Observers, can subscribe to distinct events and subsequently react to shifts in the game state.

Conclusion

Thus, systematically implementing these steps and utilising established design patterns can significantly enhance the reusability and versatility of UI components within your Unity projects. You can establish a robust UI asset library by identifying, standardizing, and organizing common UI elements as prefabs for easy integration and maintenance. Employing design patterns like MVVM, Decorator, Strategy, Composite, Singleton, and Observer further fortifies the adaptability and efficiency of UI components. This structured approach streamlines UI development and fosters a cohesive, scalable, and consistent user experience.

Thank you for reading this article. See you in the next one.