Android + AI Hub | Gemini, AppFunctions, On-Device AI & Mobile LLMs

Gemini on Android (2026 Ecosystem)

How Google's multimodal models integrate from system-level assistant down to on-device silicon.

Gemini vs Google Assistant: What Changed?

Gemini replaces Google Assistant's rigid template syntax with dynamic reasoning and on-screen awareness:

Feature	Legacy Assistant	Gemini on Android
Understanding	Voice keyword trigger	Multimodal reasoning (Screen, Audio, Text)
Context	Single intent	Cross-app conversational memory
Execution	Deep links	AppFunctions direct agentic invocation
On-Device	Basic speech parsing	Gemini Nano on AICore (Zero cloud latency)

How to enable: Settings > Apps > Default apps > Digital assistant app > Select Gemini.

How to Use Gemini on Samsung Galaxy (One UI 6/7)

Combine Samsung Galaxy AI features with Google's Gemini intelligence seamlessly:

1 Power Button Shortcut: Settings > Advanced features > Side button > Press and hold > Select Wake Gemini.

2 Circle to Search: Long-press the home button or navigation pill to invoke visual screen search powered by Gemini.

3 Screen Context Overlays: While viewing any PDF, image, or website, invoke Gemini and ask "Summarize this document" without taking a screenshot.

Supported on Galaxy S23, S24, S25, Z Fold & Z Flip

Android AppFunctions (Agentic Framework)

Google's standard framework allowing Gemini agents to call specific functions inside your Android app.

How AppFunctions Transform Android Apps

Instead of users manually opening your app, navigating screens, and tapping buttons, AppFunctions exposes structured Kotlin functions that Gemini can call directly on behalf of the user:

                  Kotlin (Android AppFunction Definition)
                  OrderAppFunctions.kt
                

// Expose app capabilities to Gemini Intelligence
@AppFunction(
    name = "createOrder",
    description = "Orders items from the catalog directly via AI voice or prompt"
)
suspend fun createOrder(
    @AppFunctionParam(description = "Item ID from catalog") itemId: String,
    @AppFunctionParam(description = "Quantity requested") quantity: Int
): OrderResult {
    return repository.placeOrder(itemId, quantity)
}

Zero UI Friction Users say "Order my usual grocery list" and Gemini invokes your AppFunction with confirmation dialog.

User Permission Gates Financial and sensitive actions require biometric fingerprint or passcode confirmation before execution.

Discovery Boost Apps exposing AppFunctions gain prime placement in Android system suggestions and lockscreen widgets.

On-Device AI with MediaPipe & Gemma

Running quantized LLMs locally with zero cloud API bills and total user privacy.

MediaPipe GenAI LlmInference

Load quantized weights (e.g. gemma-2b-it-cpu-int4.bin) directly into app memory for local execution:

                  Kotlin (MediaPipe Task)
                  OnDeviceLlm.kt
                

val options = LlmInferenceOptions.builder()
    .setModelPath("/data/local/tmp/gemma-2b.bin")
    .setMaxTokens(512)
    .setTopK(40)
    .setTemperature(0.7f)
    .build()

val inference = LlmInference.createFromOptions(context, options)
val response = inference.generateResponse("Summarize prayer rules...")

On-Device AI Silicon Hardware Tiers

Chipset	NPU TOPS	Model Compatibility
Snapdragon 8 Elite / 8 Gen 3	45+ TOPS	Gemini Nano, Gemma 7B, Llama 3 8B
Google Tensor G4 / G3	AICore TPU	Gemini Nano (System Integrated)
MediaTek Dimensity 9400	50 TOPS	Gemma 2B INT4, DeepSeek Mobile
Mid-Range (Snapdragon 7 Series)	15 TOPS	Gemma 2B INT4 via OpenCL GPU

Use dynamic model delivery to download weights only on compatible devices.

Jetpack Compose AI Streaming UI

Handle token-by-token streaming without triggering full recompositions.

Reactive Token Streaming Pattern

                  Jetpack Compose UI (Streaming Screen)
                  ChatScreen.kt
                

@Composable
fun AiAssistantScreen(viewModel: AiViewModel = viewModel()) {
    val state by viewModel.uiState.collectAsStateWithLifecycle()

    LazyColumn(modifier = Modifier.fillMaxSize().padding(16.dp)) {
        items(state.chatHistory, key = { it.id }) { message ->
            MessageCard(message)
        }
        if (state.isStreaming) {
            item(key = "active_stream") {
                StreamingTokenBubble(text = state.streamingText)
            }
        }
    }
}