# Android Viewmodel

> Best practices for implementing Android ViewModels, specifically focused on StateFlow for UI state and SharedFlow for one-off events.

- **Type:** Skill
- **Install:** `agentstack add skill-new-silvermoon-awesome-android-agent-skills-android-viewmodel`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [new-silvermoon](https://agentstack.voostack.com/s/new-silvermoon)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** Apache-2.0
- **Upstream author:** [new-silvermoon](https://github.com/new-silvermoon)
- **Source:** https://github.com/new-silvermoon/awesome-android-agent-skills/tree/main/.github/skills/architecture/android-viewmodel

## Install

```sh
agentstack add skill-new-silvermoon-awesome-android-agent-skills-android-viewmodel
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# Android ViewModel & State Management

## Instructions

Use `ViewModel` to hold state and business logic. It must outlive configuration changes.

### 1. UI State (StateFlow)
*   **What**: Represents the persistent state of the UI (e.g., `Loading`, `Success(data)`, `Error`).
*   **Type**: `StateFlow`.
*   **Initialization**: Must have an initial value.
*   **Exposure**: Expose as a read-only `StateFlow` backing a private `MutableStateFlow`.
    ```kotlin
    private val _uiState = MutableStateFlow(UiState.Loading)
    val uiState: StateFlow = _uiState.asStateFlow()
    ```
*   **Updates**: Update state using `.update { oldState -> ... }` for thread safety.

### 2. One-Off Events (SharedFlow)
*   **What**: Transient events like "Show Toast", "Navigate to Screen", "Show Snackbar".
*   **Type**: `SharedFlow`.
*   **Configuration**: Must use `replay = 0` to prevent events from re-triggering on screen rotation.
    ```kotlin
    private val _uiEvent = MutableSharedFlow(replay = 0)
    val uiEvent: SharedFlow = _uiEvent.asSharedFlow()
    ```
*   **Sending**: Use `.emit(event)` (suspend) or `.tryEmit(event)`.

### 3. Collecting in UI
*   **Compose**: Use `collectAsStateWithLifecycle()` for `StateFlow`.
    ```kotlin
    val state by viewModel.uiState.collectAsStateWithLifecycle()
    ```
    For `SharedFlow`, use `LaunchedEffect` with `LocalLifecycleOwner`.
*   **Views (XML)**: Use `repeatOnLifecycle(Lifecycle.State.STARTED)` within a coroutine.

### 4. Scope
*   Use `viewModelScope` for all coroutines started by the ViewModel.
*   Ideally, specific operations should be delegated to UseCases or Repositories.

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [new-silvermoon](https://github.com/new-silvermoon)
- **Source:** [new-silvermoon/awesome-android-agent-skills](https://github.com/new-silvermoon/awesome-android-agent-skills)
- **License:** Apache-2.0

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-new-silvermoon-awesome-android-agent-skills-android-viewmodel
- Seller: https://agentstack.voostack.com/s/new-silvermoon
- Browse the marketplace: https://agentstack.voostack.com/browse

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Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.