Exploring Android 16: App Functions

Android 16 is just about here, and with it comes an interesting new feature - App Functions. What are App Functions, what are they for, and how do I use them? In this session we'll dive into the framework changes in Android 16, the un-published AndroidX libraries, and try to build something that uses this mysterious new functionality.

Jamie Sanson is a Google Developer Expert for Android. In his spare time he likes to build things - from apps, to mechanical keyboards, to brewing systems - and photographs anything and everything. Jamie is currently working as a Staff Software Engineer in the Apps Platform team at Marks and Spencer.

Transcript

1. Exploring Android 16 App Functions I/O Extended @ Leeds Mobile - May 2025
2. Jamie Sanson Staff Software Engineer @ M&S
3. App Functions
4. Agenda App Functions - what are they? – Building an App Function – Calling an App Function – What are they for? – Predictions –
5. github.com/jamiesanson/exploring- appfunctions
7. More speci*c Intent
9. An app function is a piece of functionality that apps expose to the system for cross-app orchestration.
11. AndroidX App Functions
12. Browsing AndroidX https://cs.android.com
15. App Function packages appfunctions: backwards compatibility? – appfunctions-compiler: annotation processing is involved – appfunctions-service: seems to be a separate runtime library –
16. The [appfunctions.metadata] package de6nes a set of classes to represent metadata for AppFunctions. This metadata is designed to be similar in spirit to the OpenAPI speci6cation, which is used to describe REST APIs. 1 https://cs.android.com/androidx/platform/frameworks/support/+/androidx- main:appfunctions/appfunctions/src/main/java/androidx/appfunctions/metadata/README.md 1.
17. App Function metadata No HTTP-related things like response codes – Metadata is stored in AppSearch – Metadata originates in your APK – Common, versioned “schemas” –
18. What the code tells us Apps include “functions” – Functions have request/response modelling – Requests & responses form function metadata – Codegen will make writing functions easier –
19. Using App Functions
20. Downloading AndroidX Snapshots https://androidx.dev
21. // in settings.gradle.kts dependencyResolutionManagement { repositories { google() mavenCentral() + maven { + url = uri("https://androidx.dev/snapshots/builds/ <build-number>/artifacts/repository") + } } }
22. // in settings.gradle.kts dependencyResolutionManagement { repositories { google() mavenCentral() maven { url = uri("https://androidx.dev/snapshots/builds/<build- number>/artifacts/repository") + content { + includeGroup("androidx.appfunctions") + } } } }
24. Writing an App Function
25. AndroidX AppFunctions KSP plugin – @AppFunction – A bound Service – Various other things (schema, serialization annotation) –
27. Calling an App Function
28. AppFunctionManager Search for functions – Invoke functions – Enable and disable functions –
30. Why can’t I call App Functions?
33. What are they for?
34. Function calling (AKA MCP)
36. App Functions and function calling Function de+nitions from AppSearch – Serviced using EXECUTE_APP_FUNCTIONS – Your app is a set of tools –
37. Similar things to iOS App Intents?
38. Predictions
39. App Functions are probably for LLMs
40. We won’t see them in production for a while
41. Android could be becoming agentic
42. Conclusions
43. Conclusions App Function are better Intent s – You can build them – You can’t call them – Their use-case is probably AI, but could be used in isolation –
44. ⍰ Questions ⍰
45. Thanks! @jamiesanson