Equipment ViewModels

Equipment ViewModels manage the state and business logic for equipment component forms and lists. All follow the same architectural pattern for consistency.

Location: app/src/main/java/com/archeryapprentice/ui/equipment/viewModels/

Architecture Pattern

All equipment ViewModels follow this structure:

class ComponentViewModel(private val repository: ComponentRepository) : ViewModel() {
    // 1. Observable state for list
    private val _items = MutableStateFlow<List<Component>>(emptyList())
    val items: StateFlow<List<Component>> = _items.asStateFlow()
    
    // 2. Input state for forms
    private val _inputState = MutableStateFlow(ComponentInputState())
    val inputState: StateFlow<ComponentInputState> = _inputState.asStateFlow()
    
    // 3. CRUD operations
    init { loadItems() }
    suspend fun saveComponent(): SaveResult
    fun deleteComponent(component: Component)
    fun loadComponentForEdit(id: Long)
    fun clearInputs()
    
    // 4. Field update methods
    fun updateBrand(value: String)
    fun updateModel(value: String)
    // ... other fields
}

Component ViewModels

ArrowViewModel

File: componentViewModels/ArrowViewModel.kt Repository: ArrowRepository

State Management

data class ArrowInputState(
    val brand: String = "",
    val model: String = "",
    val length: String = "",
    val weight: String = "",
    val diameter: String = "",
    val spine: String = "",
    val quantity: String = "1",
    val identifier: String = "",
    val pointName: String = "",
    val pointWeight: String = "",
    val nockName: String = "",
    val nockWeight: String = "",
    val notes: String = "",
    val isEditing: Boolean = false,
    val editingId: Long = 0
)

Key Methods

suspend fun saveArrow(): SaveResult - Save/update arrow
fun deleteArrow(arrow: Arrow) - Delete arrow
fun loadArrowForEdit(id: Long) - Load for editing
fun toArrow(state: ArrowInputState): Arrow - Convert state to entity

Field Updates

updateBrand(value: String)
updateModel(value: String)
updateLength(value: String)
updateWeight(value: String)
updateDiameter(value: String)
updateSpine(value: String)
updateQuantity(value: String)
updateIdentifier(value: String)
updatePointName(value: String)
updatePointWeight(value: String)
updateNockName(value: String)
updateNockWeight(value: String)
updateNotes(value: String)

Validation

fun isValid(state: ArrowInputState): Boolean {
    return state.brand.isNotBlank() && state.model.isNotBlank()
}
 
fun getValidationError(): String? = when {
    brand.isBlank() -> "Brand is required"
    model.isBlank() -> "Model is required"
    else -> null
}

Pattern: SaveResult-Pattern

StabilizerViewModel

File: componentViewModels/StabilizerViewModel.kt Repository: StabilizerRepository

State Management

data class StabilizerInputState(
    val brand: String = "",
    val model: String = "",
    val length: String = "",
    val weight: String = "",
    val straightness: String = "5",  // 1-10 scale
    val notes: String = "",
    val isEditing: Boolean = false,
    val editingId: Long = 0
)

Key Methods

suspend fun saveStabilizer(): SaveResult - Save/update stabilizer
fun deleteStabilizer(stabilizer: Stabilizer) - Delete stabilizer
fun loadStabilizerForEdit(id: Long) - Load for editing
fun toStabilizer(state: StabilizerInputState): Stabilizer - Convert state to entity

Field Updates

updateBrand(value: String)
updateModel(value: String)
updateLength(value: String)
updateWeight(value: String)
updateStraightness(value: String) - Special: Constrained to 1-10 range
updateNotes(value: String)

Special Logic

fun updateStraightness(value: String) {
    val straightnessVal = value.toIntOrNull() ?: 5
    val constrainedValue = straightnessVal.coerceIn(1, 10).toString()
    _inputState.value = _inputState.value.copy(straightness = constrainedValue)
}

Other Component ViewModels

All following ViewModels use the same pattern as above with component-specific fields:

SightViewModel

File: componentViewModels/SightViewModel.kt Repository: SightRepository

Manages sight equipment (brand, model, type, adjustments)

RiserViewModel

File: componentViewModels/RiserViewModel.kt Repository: RiserRepository

Manages riser equipment (brand, model, material, weight, length)

LimbsViewModel

File: componentViewModels/LimbsViewModel.kt Repository: LimbsRepository

Manages limb equipment (brand, model, poundage, material)

BowStringViewModel

File: componentViewModels/BowStringViewModel.kt Repository: BowStringRepository

Manages bow string equipment (brand, model, material, strands, length)

PlungerViewModel

File: componentViewModels/PlungerViewModel.kt Repository: PlungerRepository

Manages plunger equipment (brand, model, tension, adjustability)

RestViewModel

File: componentViewModels/RestViewModel.kt Repository: RestRepository

Manages arrow rest equipment (brand, model, type)

AccessoryViewModel

File: componentViewModels/AccessoryViewModel.kt Repository: AccessoryRepository

Manages accessory equipment (brand, model, type, purpose)

WeightViewModel

File: componentViewModels/WeightViewModel.kt Repository: WeightRepository

Manages weight equipment (brand, model, weight, location)

Setup ViewModels

BowSetupViewModel

File: componentViewModels/BowSetupViewModel.kt Repository: BowSetupRepository

Purpose: Coordinates entire bow setup (combination of all components)

State Management

data class BowSetupInputState(
    val name: String = "",
    val riserId: Long? = null,
    val limbsId: Long? = null,
    val stringId: Long? = null,
    val sightId: Long? = null,
    val stabilizerIds: List<Long> = emptyList(),
    val arrowId: Long? = null,
    val plungerId: Long? = null,
    val restId: Long? = null,
    val accessoryIds: List<Long> = emptyList(),
    val notes: String = "",
    val isEditing: Boolean = false,
    val editingId: Long = 0
)

Key Methods

suspend fun saveBowSetup(): SaveResult - Save complete setup
fun loadBowSetupForEdit(id: Long) - Load setup with all components
fun deleteBowSetup(setup: BowSetup) - Delete setup
Component selection methods for each component type

Dependencies

Uses all equipment repositories to fetch component options
Coordinates multiple component selections into single setup

EquipmentListViewModel

File: EquipmentListViewModel.kt Purpose: Display and manage equipment inventory across all types

Key Methods

loadAllEquipment() - Load all equipment types
filterByType(type: EquipmentType) - Filter display
searchEquipment(query: String) - Search functionality
sortEquipment(sortBy: SortCriteria) - Sorting

Coordinates Multiple Repositories

class EquipmentListViewModel @Inject constructor(
    private val arrowRepository: ArrowRepository,
    private val stabilizerRepository: StabilizerRepository,
    private val sightRepository: SightRepository,
    // ... all other repositories
) : ViewModel()

Common Patterns

1. StateFlow Pattern

All ViewModels expose state using StateFlow for reactive UI:

// Private mutable state
private val _items = MutableStateFlow<List<Component>>(emptyList())
 
// Public immutable state
val items: StateFlow<List<Component>> = _items.asStateFlow()
 
// UI observes state
val items by viewModel.items.collectAsState()

Learn More: StateFlow-Pattern

2. SaveResult Pattern

All save operations return SaveResult for consistent error handling:

suspend fun saveComponent(): SaveResult {
    val state = _inputState.value
    if (!state.isValid()) {
        return SaveResult.ValidationError(
            state.getValidationError() ?: "Invalid input"
        )
    }
    return try {
        val component = toComponent(state)
        if (state.isEditing) {
            repository.updateComponent(component)
        } else {
            repository.insertComponent(component)
        }
        clearInputs()
        loadComponents()
        SaveResult.Success
    } catch (e: Exception) {
        SaveResult.Error("Failed to save: ${e.message}")
    }
}

Learn More: SaveResult-Pattern

3. Input State Pattern

Each ViewModel has a dedicated InputState data class:

data class ComponentInputState(
    val field1: String = "",
    val field2: String = "",
    val isEditing: Boolean = false,
    val editingId: Long = 0
) {
    fun isValid(): Boolean = /* validation logic */
    fun getValidationError(): String? = /* error message */
}

Benefits:

Immutable state updates (copy)
Built-in validation
Clear separation of concerns
Easy to test

4. Field Update Methods

All ViewModels provide granular field update methods:

fun updateBrand(value: String) {
    _inputState.value = _inputState.value.copy(brand = value)
}
 
fun updateModel(value: String) {
    _inputState.value = _inputState.value.copy(model = value)
}

Benefits:

Type-safe updates
Single responsibility
Easy to bind to UI components
Testable

Repository Dependencies

Each ViewModel depends on exactly one repository (except setup ViewModels):

ArrowViewModel → ArrowRepository → ArrowDao → Database
StabilizerViewModel → StabilizerRepository → StabilizerDao → Database
SightViewModel → SightRepository → SightDao → Database
... etc

Learn More: Equipment-Repositories

Testing

Equipment ViewModels are tested with:

Unit Tests: Mock repository, test state management
Integration Tests: Real repository + in-memory database
UI Tests: Compose test harness for screens

Example Test Structure:

class ArrowViewModelTest {
    @Test
    fun `saveArrow validates input`() { ... }
    
    @Test
    fun `saveArrow calls repository on success`() { ... }
    
    @Test
    fun `deleteArrow removes from list`() { ... }
}

Usage Example

@Composable
fun ArrowInputScreen(
    viewModel: ArrowViewModel = hiltViewModel()
) {
    val inputState by viewModel.inputState.collectAsState()
    val arrows by viewModel.arrows.collectAsState()
    
    Column {
        // Input fields
        OutlinedTextField(
            value = inputState.brand,
            onValueChange = viewModel::updateBrand,
            label = { Text("Brand") }
        )
        
        OutlinedTextField(
            value = inputState.model,
            onValueChange = viewModel::updateModel,
            label = { Text("Model") }
        )
        
        // Save button
        Button(
            onClick = {
                scope.launch {
                    when (val result = viewModel.saveArrow()) {
                        is SaveResult.Success -> { /* Success */ }
                        is SaveResult.Error -> { /* Show error */ }
                        is SaveResult.ValidationError -> { /* Show validation */ }
                    }
                }
            }
        ) {
            Text("Save Arrow")
        }
        
        // List of arrows
        LazyColumn {
            items(arrows) { arrow ->
                ArrowListItem(
                    arrow = arrow,
                    onEdit = { viewModel.loadArrowForEdit(arrow.id) },
                    onDelete = { viewModel.deleteArrow(arrow) }
                )
            }
        }
    }
}

Summary

Total Equipment ViewModels: 13

Component ViewModels: 10 (Arrow, Stabilizer, Sight, Riser, Limbs, String, Plunger, Rest, Accessory, Weight)
Setup ViewModels: 2 (BowSetup, EquipmentList)
Support ViewModels: 1 (EquipmentStats)

Common Patterns:

✅ StateFlow for reactive state
✅ SaveResult for error handling
✅ InputState for form management
✅ Repository pattern for data access
✅ Hilt dependency injection

Learn More:

Equipment-Repositories - Repository layer
Key-Patterns - Common patterns
Architecture-Overview - Overall architecture
Scoring-ViewModels - Scoring ViewModels
Tournament-ViewModels - Tournament ViewModels

Last Updated: October 8, 2025 File Locations: app/src/main/java/com/archeryapprentice/ui/equipment/viewModels/ Pattern Status: ✅ Consistent across all equipment ViewModels

Archery Apprentice Documentation

Explorer

equipment-view-models

Equipment ViewModels

Architecture Pattern

Component ViewModels

ArrowViewModel

State Management

Key Methods

Field Updates

Validation

StabilizerViewModel

State Management

Key Methods

Field Updates

Special Logic

Other Component ViewModels

SightViewModel

RiserViewModel

LimbsViewModel

BowStringViewModel

PlungerViewModel

RestViewModel

AccessoryViewModel

WeightViewModel

Setup ViewModels

BowSetupViewModel

State Management

Key Methods

Dependencies

EquipmentListViewModel

Key Methods

Coordinates Multiple Repositories

Common Patterns

1. StateFlow Pattern

2. SaveResult Pattern

3. Input State Pattern

4. Field Update Methods

Repository Dependencies

Testing

Usage Example

Summary

Graph View

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