field/me.tbsten.compose.preview.lab.field/ListField

ListField

open class ListField<Value>(label: String, initialValue: List<Value>, elementField: ListField.ElementFieldScope.() -> MutablePreviewLabField<Value>, defaultValue: () -> Value = { initialValue.firstOrNull() ?: error("ListField requires a non-empty initialValue or an explicit defaultValue") }) : MutablePreviewLabField<List<Value>>

A field for editing List values with support for dynamic element insertion and deletion.

ListField provides a UI for editing list collections where each element is represented by its own field. Elements can be inserted at any position using insert buttons, and the field automatically maintains correct indices.

Usage

PreviewLab {
    val characters by fieldValue {
        ListField(
            label = "characters",
            initialValue = listOf("Alice", "Bob", "Charlie"),
            elementField = { StringField(label, initialValue) },
        )
    }
    Text(characters.joinToString(", "))
}

Parameters

Value

The type of elements in the list.

label

Label displayed in the UI for this field.

initialValue

Initial list value.

elementField

Factory function to create a field for each element. Receives ElementFieldScope with the element's label (index) and initial value.

defaultValue

Factory function to create a default value when inserting new elements. Defaults to the first element of initialValue if available.

Constructors

ListField

constructor(label: String, initialValue: List<Value>, elementField: ListField.ElementFieldScope.() -> MutablePreviewLabField<Value>, defaultValue: () -> Value = { initialValue.firstOrNull() ?: error("ListField requires a non-empty initialValue or an explicit defaultValue") })

Types

ElementFieldScope

inner class ElementFieldScope

Scope provided to elementField factory function for creating element fields.

Properties

coroutineScope

open override val coroutineScope: CoroutineScope

initialValue

open override val initialValue: List<Value>

Default value for this field.

label

open override var label: String

The label for this field. This is not used in any of the program logic, but only for display purposes, so it is best to set it in a language that is easy for your team members to read.

value

open override var value: List<Value>

Current value of this PreviewLabField.

valueFlow

open override val valueFlow: Flow<List<Value>>

Functions

component1

open operator override fun component1(): List<Value>

component2

open operator override fun component2(): (List<Value>) -> Unit

Content

@Composable

open override fun Content()

Composable, which displays the main UI for this Field. If you want to customize the UI, you can override this method in your PreviewLabField to customize the UI.

DefaultFieldView

@Composable

fun <Value> PreviewLabField<Value>.DefaultFieldView(modifier: Modifier = Modifier, menuItems: List<PreviewLabField.ViewMenuItem<Value>> = ViewMenuItem.defaults<Value>(this), content: @Composable () -> Unit = { Content() })

Default UI implementation of me.tbsten.compose.preview.lab.PreviewLabField.View. Display a label and draw the content below it.

FieldLabelHeader

@Composable

fun <Value> PreviewLabField<Value>.FieldLabelHeader(menuItems: List<PreviewLabField.ViewMenuItem<Value>> = ViewMenuItem.defaults<Value>(this))

Display the label of PreviewLabField.

nullable

fun <Value : Any> PreviewLabField<Value>.nullable(initialValue: Value? = this.initialValue): NullableField<Value>

Create a PreviewLabField that makes the receiver's PreviewLabField nullable.

onCleared

open fun onCleared()

serializer

open override fun serializer(): KSerializer<List<Value>>?

Returns a KSerializer for this field's value type, or null if serialization is not supported.

testValues

open fun testValues(): List<List<Value>>

Returns a list of representative values for this field to be used in automated testing.

TextFieldContent

@Composable

fun <Value> MutablePreviewLabField<Value>.TextFieldContent(toString: (Value) -> String, toValue: (String) -> Result<Value>, modifier: Modifier = Modifier, prefix: @Composable () -> Unit? = null, suffix: @Composable () -> Unit? = null, placeholder: @Composable () -> Unit? = null)

Helper for UI of Fields that can be input with TextField.

transform

fun <BaseValue, TransformedValue> MutablePreviewLabField<BaseValue>.transform(transform: (BaseValue) -> TransformedValue, reverse: (TransformedValue) -> BaseValue, label: String = this.label, initialValue: TransformedValue = transform(this.value)): TransformField<BaseValue, TransformedValue>

Transforms a MutablePreviewLabField to work with a different value type.

valueCode

open override fun valueCode(): String

Returns a Kotlin code string representing the current value of this field.

View

@Composable

open fun View(menuItems: List<PreviewLabField.ViewMenuItem<List<Value>>>)

Composable, which displays the entire UI for this Field. If you want to customize the UI, you can override this method in your PreviewLabField to customize the UI. However, in many cases where the UI is customized, overriding the content method is more appropriate.

withDecrementHint