MutableFloat | API reference | Android Developers

Skip to main content

Essentials

Build AI experiences
Build AI-powered Android apps with Gemini APIs and more.
Get started

Get started
Create your first app. Use Compose for UI and adaptive app development to support multiple device form factors.
Hello, world!
Adaptive apps
Compose for UI
AI-powered IDE
Monetization with Play ↗️
Developer Verification
Registered App Stores

Optimize by form factor
Build apps that optimize the user experience on phones, tablets, foldables, cars, XR, and more.
Phones, tablets, foldables
Android for Cars
Android TV
Android XR
Googlebook
ChromeOS
Wear OS

Build by category
Learn to build for your use case by following Google's prescriptive and opinionated guidance.
Games
Camera & media
Social & messaging
Health & fitness
Productivity
Enterprise apps

Get the latest
Stay in touch with the latest releases throughout the year, join our preview programs, and give us your feedback.
Latest updates
Experimental updates
Android Studio preview
Jetpack & Compose libraries
Wear OS releases
Privacy Sandbox ↗️

Design & Plan

Excellent Experiences
Build the best experiences for your best users.
Learn more

UI Design
Design a beautiful user interface using Android best practices.
Design for Android
Mobile
Desktop experiences
XR Headsets & XR Glasses
AI Glasses
Widgets
Wear OS
Android TV
Android for Cars

Architecture
Design robust, testable, and maintainable app logic and services.
Introduction
Libraries
Navigation
Modularization
Testing
Kotlin Multiplatform

Quality
Plan for app quality and align with Play store guidelines.
Overview
Core value
User experience
Accessibility
Technical quality
Excellent Experiences

Security
Safeguard users against threats and ensure a secure Android experience.
Overview
Privacy
Permissions
Identity
Fraud prevention

Develop

Build more with agents in Android
Turn prompts into real Android experiences using your favorite agents.
Learn more
Get Android CLI

Core areas
Get the samples and docs for the features you need.
Samples
Multidevice support
User interfaces
Background work
Data and files
Connectivity
All core areas ⤵️

Tools and workflow
Use the IDE to write and build your app, or create your own pipeline.
Write and debug code
Build projects
Test your app
Performance
Command-line tools
Gradle plugin API
Android Bench
Build with agents

Device tech
Write code for form factors. Connect devices and share data.
Phones, tablets, foldables
Googlebook
ChromeOS
Android for Cars
Android TV
Android XR
Wear OS
Android Health
Better Together
All devices ⤵️

Libraries
Browse API reference documentation with all the details.
Android platform
Jetpack libraries
Compose libraries
Google Play services ↗️
Google Play SDK index ↗️

Google Play

Play Console
Publish your app or game and grow your business on Google Play.
Learn more ↗️
Go to Play Console

Fundamentals
Learn how to engage users, monitize, and secure your app.
Play Monetization
Play Integrity
Android vitals
Play Policies
Play Programs ↗️

Games Dev Center
Develop and deliver games. Get tools, downloads, and samples.
Overview
Play Asset Delivery
Play Games Services
Play Games on PC
Level Up guidelines
All Play guides ⤵️

Libraries
Browse API reference documentation with all the details.
Play Feature Delivery
Play In-app Updates
Play In-app Reviews
Play Install Referrer
Google Play services ↗️
Google Play SDK index ↗️
All Play libraries ⤵️

Tools & resources
Tools for publishing, promoting, and managing your app.
Android App Bundles
Brand & marketing
Play Console APIs ↗️

Blog

the Android Developer's Blog
Read the latest
Explore the authors →

Explore categories
Product News

Stay in the loop with the latest updates, feature releases, and behind-the-scenes looks at how we’re evolving.
Community

Discover stories from our users, spotlight features, and the collaborative projects that bring us all together.

How-tos

From quick tips to deep-dive tutorials, these step-by-step guides are designed to help you work smarter and faster.
Case Studies

Real-world results from real-world users. Explore how different teams use our tools to achieve their goals.

Events & Programs

Get the details on upcoming webinars, workshops, meetups, and special initiatives designed to help you grow.
Documentation

Access detailed manuals, API references, and technical specifications to help you build and integrate with confidence.

/

English
Deutsch
Español – América Latina
Français
Indonesia
Polski
Português – Brasil
Tiếng Việt
中文 – 简体
日本語
한국어

Android Studio

Sign in

API reference

Essentials
- More
Design & Plan
- More
Develop
- More
Google Play
- More
Blog
- More
Android Studio

Android API Reference
Overview
Android Platform
Packages

Play Console
Learn more ↗️
Go to Play Console
Fundamentals
Play Monetization
Play Integrity
Android vitals
Play Policies
Play Programs ↗️
Games Dev Center
Overview
Play Asset Delivery
Play Games Services
Play Games on PC
Level Up guidelines
All Play guides ⤵️
Libraries
Play Feature Delivery
Play In-app Updates
Play In-app Reviews
Play Install Referrer
Google Play services ↗️
Google Play SDK index ↗️
All Play libraries ⤵️
Tools & resources
Android App Bundles
Brand & marketing
Play Console APIs ↗️

the Android Developer's Blog
Read the latest
Explore the authors →
Explore categories
Product News
Community
How-tos
Case Studies
Events & Programs
Documentation

Android Developers
Develop
API reference

Stay organized with collections Save and categorize content based on your preferences.

Added in API level 21
Deprecated in API level 28

Summary: Fields