Android UI System A Deep Dive

What is Android UI system? It’s the heart and soul of every Android app, the invisible architect shaping how users interact with their devices. Imagine a bustling city, each building a distinct app, meticulously crafted and connected by a sophisticated network – that’s the Android UI system in action. This system dictates how users navigate, tap, and explore within their applications, creating a seamless and engaging experience.

From simple buttons to complex animations, every element plays a crucial role in shaping the user journey.

This exploration delves into the fundamental components of the Android UI system, revealing the intricate design principles and patterns that underpin its effectiveness. We’ll examine various layout structures, common UI widgets, and essential design principles that contribute to creating intuitive and user-friendly interfaces. Moreover, we’ll uncover strategies for optimizing performance and ensuring accessibility, empowering developers to craft truly exceptional Android experiences.

Introduction to Android UI System

The Android UI system is a powerful and flexible framework for building visually appealing and interactive applications. It’s designed to provide a consistent user experience across a wide range of devices, from smartphones to tablets. Understanding its core concepts and components is essential for creating effective and engaging Android apps.The Android UI system’s fundamental design principles prioritize user-centricity, providing a smooth and intuitive interaction flow.

This approach ensures a consistent user experience across a vast array of Android devices, regardless of their specific hardware specifications. This consistency is achieved through a robust set of tools and guidelines that developers can leverage to craft high-quality applications.

Fundamental Concepts

The Android UI system is built upon several key concepts. These concepts are interconnected, creating a robust framework that supports a wide range of UI elements and interactions. Crucially, they are designed to adapt seamlessly to different screen sizes and resolutions, ensuring consistent performance across various devices. Understanding these fundamental concepts is crucial to effective UI design and development.

Key Components and Their Roles

The Android UI system comprises several interconnected components, each playing a distinct role in the overall user experience. These components work together to facilitate seamless interactions and display of information. They are designed with modularity in mind, enabling developers to easily integrate and modify specific components without disrupting the entire system.

Component Name	Description	Function
Activity	A fundamental building block representing a single screen or view within an application.	Handles user interactions, manages UI elements, and presents content to the user.
View	Represents a visual element on the screen, like a button, text field, or image.	Displays information, responds to user input, and can be customized extensively.
Layout	Defines the structure and arrangement of views within an activity.	Controls how different views are positioned and sized on the screen, creating the visual layout of an application.
Resources	Contain various assets like images, strings, and colors, used by the UI.	Provides reusable assets for consistency and maintainability across different parts of the application.
Fragments	Reusable modules of UI that can be added or removed from an Activity.	Enable modularity, allowing for dynamic updates and better organization of complex UIs.

UI Element Interactions

A button click can trigger an action, like displaying a new screen or updating data. A user tapping on a list item could load detailed information, demonstrating the interplay between different components. A text field’s input could be validated and used to update other elements on the screen. These interactions are designed to be intuitive and consistent, improving the overall user experience.

UI Components and Widgets

Android UI development thrives on a robust set of components, meticulously crafted to ensure seamless user interaction and a polished user experience. These components, or widgets, are the building blocks of any Android app, allowing developers to create engaging and functional interfaces. Understanding their varied functionalities and design principles is crucial for crafting intuitive and user-friendly applications.The key to a compelling Android app lies in the effective use of its UI components.

These elements, ranging from simple buttons to complex layouts, form the visual backbone of the application. Their proper implementation directly influences user engagement and satisfaction. By grasping the intricacies of these components, developers can craft interfaces that not only look good but also perform optimally.

Common UI Components, What is android ui system

A plethora of UI components are available in the Android toolkit, each designed for specific tasks. Buttons, text fields, and image views are fundamental elements, while more complex layouts provide structure and organization. Mastering these building blocks empowers developers to create interfaces that cater to diverse user needs.

• Buttons: Essential for user actions, buttons trigger specific functionalities when tapped. They come in various shapes and sizes, allowing developers to tailor them to fit the overall design. A well-placed button can streamline user flow, ensuring a smooth and intuitive experience.
• Text Views: Used to display textual content, text views are crucial for conveying information to the user. They allow for flexibility in formatting, including font size, style, and color, enhancing the visual appeal of the application.
• Image Views: Crucial for incorporating visual elements, image views allow developers to seamlessly integrate images into their apps. These can be simple icons or high-resolution photographs, contributing to the visual richness and appeal of the application.
• Edit Texts: Enabling users to input data, edit texts are fundamental for collecting user information. They allow users to type, edit, and submit data, crucial for applications requiring user input.
• Layouts: The foundation for arranging other components, layouts dictate the spatial arrangement of elements within an application. Different layout types offer varied organizational structures, ensuring a coherent and aesthetically pleasing user interface.

Widget Functionalities

The diverse functionalities of Android widgets cater to a wide range of application needs. Each widget is carefully designed to fulfill specific tasks, enabling developers to create highly functional and intuitive user interfaces.

• Buttons trigger actions, such as opening a new screen or updating data. For example, a “Login” button in a social media app directs the user to the login screen.
• Text views display information, ranging from simple labels to complex paragraphs. An app displaying weather forecasts would utilize text views to display the forecast details.
• Image views enhance the visual appeal of the application. In a photo-sharing app, image views are vital for displaying the uploaded images.
• Edit texts allow users to input data, essential in forms and data entry applications. A registration form in an e-commerce app uses edit texts for collecting user details.
• Layouts manage the positioning and arrangement of other components, ensuring a well-structured and visually appealing user interface. A layout in a game app might position buttons, images, and text views to guide the player through the game.

Designing User Interfaces

The principles behind designing effective Android user interfaces revolve around user-centered design. This emphasizes user experience and intuitive interaction. Key principles include simplicity, consistency, and accessibility.

• Simplicity: Clear and straightforward design choices lead to a user-friendly experience. Complex interfaces can be confusing and overwhelming, so maintaining a simple design is vital.
• Consistency: Uniform design elements across the application foster familiarity and ease of use. Consistency ensures users can navigate the app intuitively.
• Accessibility: Ensuring the interface is usable by all users, regardless of their abilities, is crucial. Accessibility features ensure inclusivity and usability for a broader user base.

Examples of UI Widgets in Action

A well-designed shopping app might use buttons to add items to a cart, text views to display product details, and image views to showcase product images. A social media application utilizes buttons for posting updates, text views for displaying comments, and image views for sharing photos.

UI Components Table

Component	Use	Implementation Scenarios
Button	Triggers actions	“Submit,” “Cancel,” “Next”
TextView	Displays text	Labels, messages, descriptions
ImageView	Displays images	Product photos, profile pictures
EditText	User input	Forms, search bars
Layout	Organizes components	Creating a structure for the screen

UI Layouts and Structures

Android UI layouts are the backbone of your app’s visual structure. They define how UI elements are arranged and interact on the screen. Understanding these structures is crucial for creating engaging and user-friendly interfaces. Mastering layouts allows you to craft dynamic and responsive designs that adapt to different screen sizes and orientations.Different layouts offer distinct advantages, each suited to specific design needs.

Whether you need a simple linear arrangement or a complex, flexible structure, Android provides the tools to build it. Understanding these layout types is paramount for creating efficient and aesthetically pleasing interfaces.

Layout Types

Android offers a variety of layout managers, each with its own characteristics. Choosing the appropriate layout type significantly impacts the visual appeal and functionality of your app. Each type has a unique purpose and strengths, which should be considered during the design process.

• LinearLayout: This layout arranges elements in a single row or column. It’s straightforward to use and ideal for simple, linear structures. It’s often used for lists, forms, or other elements where a simple vertical or horizontal flow is required. For example, a list of items or a series of buttons in a row are well-suited for LinearLayout.

• RelativeLayout: This layout allows you to position elements relative to each other or other elements. It provides more flexibility compared to LinearLayout, enabling complex arrangements. It’s perfect for layouts where elements need precise positioning and relationships. For instance, a layout where a button needs to be placed below an image, or text needs to align to the right of an input field.

• FrameLayout: This layout simply stacks elements one on top of the other. It’s a basic layout that’s often used for overlaying elements, such as dialog boxes or menus. It is frequently used for positioning views one on top of another, with the bottom view obscuring the top view.
• TableLayout: This layout allows you to create tables. It’s useful for structured data displays, such as tabular data or calendar views. It’s essential for displaying information in a grid-like format, like a spreadsheet or timetable.
• ConstraintLayout: This modern layout is highly flexible and allows for complex layouts with constraints. It’s capable of handling intricate designs and offers excellent control over positioning and sizing. It’s best for sophisticated layouts where precise control over element placement and responsiveness are essential.

Layout Manager Comparison

The choice of layout manager depends on the specific requirements of your application. This table provides a comparative overview.

Layout Type	Advantages	Disadvantages
LinearLayout	Simple to use, easy to manage, suitable for basic layouts.	Limited flexibility, not ideal for complex arrangements.
RelativeLayout	Offers more flexibility for complex layouts, precise positioning.	Can become complex to manage for intricate designs, increased code length.
FrameLayout	Simple stacking of elements, easy to overlay views.	Limited control over positioning and relationships, not ideal for more sophisticated designs.
TableLayout	Ideal for structured data, easy to create tabular views.	Can become unwieldy for complex tables, limited flexibility.
ConstraintLayout	Superior flexibility and control over layout, excellent for complex designs.	Steeper learning curve, potentially more complex code.

Example Usage

Using these layouts, you can arrange UI elements in numerous ways. A simple example might involve placing buttons in a row using LinearLayout, while a more complex example could involve positioning elements dynamically based on user interaction. These examples demonstrate how to create visually appealing and responsive user interfaces.

UI Design Principles and Patterns

Crafting a compelling Android user interface is more than just slapping together widgets. It’s about understanding the principles that guide user experience and applying effective design patterns to create intuitive and engaging apps. A well-designed UI not only looks good but also leads to higher user satisfaction and ultimately, greater success for your application.Effective UI design fosters a seamless and enjoyable interaction between the user and the application.

Understanding the fundamental principles of UI design allows developers to create applications that are not only visually appealing but also functionally intuitive. This, in turn, enhances user satisfaction and boosts the overall success of the application.

Essential Design Principles

Understanding and implementing key design principles is crucial for creating user-friendly Android applications. These principles guide the creation of interfaces that are not only visually appealing but also effectively communicate functionality and lead users to desired actions.

• Consistency: Maintaining a consistent visual language and interaction patterns across the application ensures predictability and ease of use for the user. This includes using similar button styles, navigation structures, and feedback mechanisms throughout the app.
• Clarity: The interface should be easy to understand. Information should be presented in a clear and concise manner, using appropriate visual cues and avoiding unnecessary complexity. Clear labels, concise text, and intuitive layouts are essential.
• Accessibility: Android applications must be designed with accessibility in mind, ensuring usability for users with disabilities. This includes considerations for screen readers, color contrast, and other accessibility features.
• Simplicity: A clean and uncluttered interface is crucial. Avoid overwhelming the user with too much information or visual noise. Focus on essential elements and keep the design straightforward.
• Feedback: Provide clear and immediate feedback to user actions. This could be visual cues, auditory signals, or other mechanisms to inform the user that their input has been registered and processed.

Common Design Patterns

Design patterns offer proven solutions for common UI design challenges. Using established patterns ensures consistency, efficiency, and a recognizable structure for users.

• Navigation Patterns: These patterns dictate how users move through the application. Common examples include tabbed navigation, drawer menus, and hierarchical structures. Each pattern offers different advantages depending on the application’s complexity and intended functionality.
• Input Patterns: Designing intuitive input methods is critical for user experience. Effective examples include forms, search bars, and various input widgets that cater to specific data types.
• Layout Patterns: Layout structures are critical for organizing content effectively. Well-designed layouts guide users through the application and present information in a logical order. Examples include grid layouts, linear layouts, and relative layouts.

Examples of Successful UI Designs

Many successful Android applications have demonstrated effective UI design principles and patterns. Observing these examples can provide valuable insight and inspiration.

• Material Design: Google’s Material Design provides a comprehensive set of guidelines and components for building beautiful and functional UIs. Apps following these guidelines often provide a visually appealing and intuitive user experience.
• Modern UI Design Principles: Modern Android applications emphasize user experience, incorporating principles like minimalist aesthetics, clear navigation, and effective feedback. The user is the focal point in this approach.
• User-centered design: Applications that prioritize the user’s needs and preferences often demonstrate excellent UI design. Gathering user feedback is crucial for optimizing the interface and refining its functionality.

Creating a User-Friendly Interface

A user-friendly interface is essential for successful Android applications. It should be easy to navigate, intuitive to use, and aesthetically pleasing.

Design Principle	Description	Example Application
Consistency	Maintaining a consistent look and feel throughout the app	Gmail, Google Maps
Clarity	Presenting information clearly and concisely	Evernote, Trello
Accessibility	Ensuring usability for users with disabilities	Voice assistants, screen reader support
Simplicity	Removing unnecessary complexity and clutter	Instagram, Twitter
Feedback	Providing clear feedback on user actions	Games, productivity apps

Interaction and User Experience: What Is Android Ui System

Android apps thrive on intuitive interactions, seamlessly guiding users through their tasks. A well-designed UI isn’t just visually appealing; it’s a crucial element for fostering a positive user experience. Understanding user interaction patterns and accessibility principles is paramount for creating apps that are both enjoyable and effective.User interaction is a dynamic dance between the user and the application.

Users expect clear pathways for achieving their goals, avoiding frustration and confusion. This is achieved by crafting a user experience that feels natural and anticipates their needs. By paying close attention to the nuances of interaction, developers can build apps that empower users to achieve their objectives with ease.

User Interaction Methods

Understanding how users interact with your app is fundamental to crafting a positive experience. Different interaction methods cater to diverse user preferences and needs. By carefully considering these methods, you can create an intuitive and enjoyable app.

• Touch interactions, including taps, swipes, and gestures, are the primary methods for interacting with Android UI elements. These actions provide direct control and a responsive feedback loop, which makes the interaction feel natural and engaging.
• Voice commands and other input methods like text entry can be integrated to cater to users with diverse needs or preferences. This diversity is vital to ensure the application is usable by a wide range of people.
• Navigation mechanisms, like buttons, menus, and tabs, allow users to explore and move through different parts of the app. A well-structured navigation system simplifies the user journey, allowing them to quickly find what they need.
• Notifications provide updates and alerts to users. Well-designed notifications should be clear, concise, and relevant to the user’s needs, avoiding overwhelming or distracting them. A notification system should enhance the user experience rather than hinder it.

Importance of User Experience

A positive user experience is crucial for the success of any Android application. A well-crafted UX enhances user satisfaction, encourages repeat use, and promotes positive word-of-mouth marketing. It’s the bridge between the app’s functionality and the user’s needs.

Creating an Engaging and Interactive Experience

Interactive elements, like animations and transitions, make the app feel alive and responsive. These elements can enhance the user’s engagement and make the experience more memorable. Consider the context of each interaction to ensure the app’s feel is consistent with the user’s expectations.

Accessibility Considerations

Accessibility is paramount in Android UI design. Designers must ensure the app is usable by people with disabilities. This includes considering factors like color contrast, screen reader compatibility, and keyboard navigation. This focus is critical to making the app usable for everyone.

User Interaction Methods Table

Interaction Method	Benefits	Examples
Tap	Simple, direct interaction; widely understood.	Selecting a button, opening a menu item.
Swipe	Intuitive navigation, quick transitions.	Scrolling through a list, navigating between pages.
Pinch to Zoom	Flexible zooming for images and maps.	Viewing images at different magnifications.
Long Press	Accessing contextual actions.	Copying text, sharing an item.
Voice Input	Hands-free interaction for users with disabilities or convenience.	Dictating text, searching for content.

UI Development Tools and Frameworks

Crafting compelling Android UIs is a journey, not a sprint. A well-chosen set of tools can significantly accelerate this journey, transforming it from a tedious chore into a creative exploration. This section explores essential tools and frameworks that empower developers to build stunning and functional interfaces.

Common Tools for Android UI Development

These tools are your secret weapons, providing the structure and functionalities to bring your UI designs to life. From designing layouts to handling user interactions, they streamline the entire development process.

• Android Studio: A comprehensive Integrated Development Environment (IDE) tailored for Android development. It provides a robust environment for coding, debugging, and testing applications. Android Studio’s powerful features include intelligent code completion, intuitive debugging tools, and built-in support for various UI design tools. It’s an invaluable asset for both beginners and experienced developers.
• Jetpack Compose: A modern declarative UI toolkit that allows you to describe the UI in a more concise and expressive way. Jetpack Compose significantly enhances developer productivity by promoting code reusability and making UI development more intuitive. The declarative nature leads to more maintainable and efficient code, enabling rapid iteration and improvements in the user interface.
• Material Design Components: A collection of pre-built UI components based on Google’s Material Design guidelines. These components are readily available and can be seamlessly integrated into your projects, saving you valuable time and effort. Using Material Design Components ensures consistency and adherence to best practices, resulting in a polished and user-friendly experience.
• ConstraintLayout: A powerful layout manager in Android that allows you to create complex and flexible UI layouts. It offers excellent control over the position and size of UI elements, allowing you to arrange them precisely and adapt them dynamically based on screen size and orientation. ConstraintLayout is particularly useful for intricate UI designs.
• XML Editors: Specialized editors such as the one integrated within Android Studio enable efficient manipulation of XML files, which are essential for defining UI layouts. They offer features like syntax highlighting, validation, and code completion to assist in crafting well-structured XML layouts, making the process smoother.

Features and Capabilities of Popular UI Design Tools

Different tools excel in different areas, enhancing your workflow and ensuring efficient development. Understanding these features is crucial to leveraging the full potential of these tools.

• Android Studio’s design tools offer a visual interface for designing UI layouts. You can drag and drop UI elements, modify their properties, and preview your design in real-time. The integrated design tools simplify the process of designing and implementing complex layouts.
• Jetpack Compose’s declarative approach lets you define the UI by describing its structure and state, rather than explicitly manipulating views. This approach significantly reduces boilerplate code and leads to more concise and readable code. It facilitates a more streamlined development process, fostering efficient UI creation and modification.
• Material Design Components provide a consistent and well-structured set of UI elements. This ensures visual consistency across applications and maintains a user-friendly experience. They reduce development time and promote a polished look, helping to maintain brand identity.

Benefits of Using These Tools

Employing these tools yields a multitude of benefits. These advantages contribute to a more productive development cycle and a more user-friendly final product.

• Increased Productivity: Tools like Android Studio and Jetpack Compose streamline the development process, allowing developers to focus on creating innovative features rather than getting bogged down in repetitive tasks.
• Enhanced Code Maintainability: Tools like Jetpack Compose and ConstraintLayout promote well-structured and organized code, which simplifies future modifications and updates.
• Improved UI Consistency: Tools like Material Design Components help to maintain a consistent visual language and user experience across different parts of the application.

Creating UI Elements with These Tools

Implementing these tools involves various steps, from designing layouts to incorporating elements. Understanding these steps is vital for effectively utilizing the tools.

• Using Android Studio: Create a new Android project and utilize the integrated design tools to define UI elements, add constraints, and preview the layout. Modifying properties and connecting elements are essential steps in the process.
• Employing Jetpack Compose: Define UI elements declaratively using composables, specify their properties, and chain them together to create the desired UI structure. Experimenting with different composables is key to crafting engaging UI elements.
• Leveraging Material Design Components: Select appropriate components from the Material Design library, customize their attributes, and integrate them into your layout to achieve the desired visual style.

Summary of UI Development Tools

This table summarizes the different tools and their functionalities.

Tool	Functionality
Android Studio	Comprehensive IDE for Android development, including design tools, debugging, and testing.
Jetpack Compose	Modern declarative UI toolkit for building Android UIs.
Material Design Components	Pre-built UI components based on Material Design guidelines.
ConstraintLayout	Powerful layout manager for creating complex and flexible layouts.
XML Editors	Specialized editors for manipulating XML files defining UI layouts.

Performance Optimization

Optimizing Android UI performance is crucial for a positive user experience. A smooth, responsive interface directly impacts user engagement and satisfaction. A laggy or unresponsive app can quickly lead to frustration and lost users. Let’s explore techniques to craft fluid and efficient Android UIs.

Efficient Layout Management

Proper layout management is paramount for UI performance. Complex layouts, especially those with many nested views, can lead to performance bottlenecks. Using appropriate layout managers and optimizing their hierarchy is essential. Employing a declarative approach to layout design, utilizing constraints, and strategically placing views within the layout hierarchy can significantly reduce rendering overhead. Avoid redundant calculations and updates by using efficient view merging strategies.

View Optimization Strategies

Careful selection and optimization of UI elements significantly impacts performance. Excessive use of complex views or views with heavy rendering demands (like custom views) can introduce lag. Consider using simpler, lightweight alternatives whenever possible. Recycling views when possible, especially in list views and recycler views, minimizes object creation and garbage collection overhead. Employing techniques like view holder patterns in list views further enhances performance by reusing view components, and caching frequently used images to avoid repeated downloads.

Handling Large Datasets and Complex Interactions

Handling large datasets efficiently is critical in apps displaying extensive information, such as social media feeds or contact lists. Implementing techniques such as lazy loading and pagination is crucial. Lazy loading loads data only when it’s needed, preventing unnecessary initial load times and improving initial responsiveness. Pagination displays data in smaller batches, reducing the amount of data processed at once.

For complex interactions, consider using asynchronous operations. Tasks such as network requests or database queries should be performed in separate threads to avoid blocking the main UI thread.

Background Processing and Thread Management

Background threads are essential for tasks that might take a significant amount of time, preventing the UI from freezing. Utilizing threads correctly and effectively is crucial. Avoid performing computationally intensive tasks directly on the main thread. This ensures that the UI remains responsive, even during time-consuming operations. Employ AsyncTask, threads, or the more modern approach of using Kotlin coroutines for performing these tasks.

Memory Management

Memory leaks can significantly impact UI performance. Properly managing resources, particularly memory, is critical. Implement strategies to release unused objects and resources, especially memory-intensive views and large image data. Regularly monitor memory usage, particularly when handling large datasets.

Common Performance Issues and Solutions

Performance Issue	Solution
Laggy UI	Optimize layouts, reduce nested views, use appropriate layout managers, and employ view recycling strategies.
Slow rendering	Simplify views, avoid complex custom views, and use lightweight alternatives.
Large dataset loading	Implement lazy loading and pagination techniques to load data incrementally.
Heavy computation on main thread	Move time-consuming tasks to background threads, using coroutines, threads, or AsyncTask.
Memory leaks	Regularly monitor memory usage and use appropriate memory management strategies.

Accessibility Considerations

Embarking on the journey of crafting Android UIs is not just about aesthetics; it’s about creating experiences that are inclusive and welcoming to everyone. Accessibility isn’t an afterthought; it’s an integral part of the design process, ensuring that your app can be used by people with a wide range of abilities. It’s a commitment to building a digital world where everyone can participate.Accessibility in Android UI design goes beyond mere compliance; it’s about fostering empathy and understanding.

Designing with accessibility in mind results in applications that are not only usable but also enjoyable for everyone. This approach not only benefits users with disabilities but also enhances the user experience for all. Imagine a world where technology empowers everyone, regardless of their limitations.

Importance of Accessibility

Ensuring that Android applications are accessible benefits everyone. Users with disabilities benefit from increased usability, and all users can appreciate the enhanced experience. Accessibility fosters inclusivity and promotes a more equitable digital landscape. This approach builds trust and enhances the overall perception of your application.

Making Android UIs Accessible

Creating accessible Android UIs requires a conscious effort throughout the design and development process. It’s about considering various needs, from screen readers to alternative input methods. Thorough research and user testing with diverse users are crucial for ensuring the application meets the diverse needs of your audience. This approach will lead to a more satisfying and enjoyable experience for all.

Implementing Accessibility Features

Utilizing the Android Accessibility API is key to creating applications that are usable by individuals with various disabilities. This approach ensures compliance with accessibility guidelines and enhances user inclusivity. Providing alternative text for images, using clear and concise labels for UI elements, and structuring content logically are just a few examples of essential practices.

Guidelines and Best Practices

Adhering to the Android design guidelines for accessibility is paramount. These guidelines provide a structured approach to ensure that applications are accessible to users with disabilities. Ensuring sufficient color contrast, providing clear and concise instructions, and utilizing appropriate headings and labels are just a few examples of crucial elements. These practices lead to improved usability and a more welcoming digital experience.

Example: HTML Table of Accessibility Features

Accessibility Feature	Implementation	Benefit
Screen Reader Compatibility	Using descriptive text alternatives for images and controls.	Allows users with visual impairments to understand content using screen readers.
Keyboard Navigation	Designing UI elements with clear keyboard navigation paths.	Facilitates use for users who cannot use a mouse or touch screen.
Sufficient Color Contrast	Ensuring sufficient color contrast between text and background colors.	Improves readability for users with visual impairments or color blindness.
Clear Instructions	Providing clear and concise instructions for interacting with the UI.	Increases usability for all users, including those with cognitive disabilities.