PickerState

Artifact: androidx.wear.compose:compose-material3

class PickerState : ScrollableState

A state object that can be hoisted to observe item selection.

In most cases, this will be created via rememberPickerState.

Summary

Public companion properties
`Saver<PickerState, Any>`	`Saver` The default `Saver` implementation for `PickerState`.

Public constructors
`PickerState( initialNumberOfOptions: @IntRange(from = 1) Int, initiallySelectedIndex: @IntRange(from = 0) Int, shouldRepeatOptions: Boolean )`

Public functions
`suspend Unit`	`animateScrollToOption(index: Int)` Animate (smooth scroll) to the given option at `index`.
`open Float`	`dispatchRawDelta(delta: Float)`
`open suspend Unit`	`scroll(scrollPriority: MutatePriority, block: suspend ScrollScope.() -> Unit)`
`suspend Unit`	`scrollToOption(index: Int)` Instantly scroll to an option.

Public properties
`open Boolean`	`canScrollBackward`
`open Boolean`	`canScrollForward`
`open Boolean`	`isScrollInProgress`
`Int`	`numberOfOptions` Represents how many different choices are presented by this `Picker`
`Int`	`selectedOptionIndex` Index of the selected option (i.e. at the center).
`Boolean`	`shouldRepeatOptions` if true (the default), the options will be repeated.

Inherited properties

From androidx.compose.foundation.gestures.ScrollableState

`open Boolean`	`lastScrolledBackward`
`open Boolean`	`lastScrolledForward`

Public companion properties

Saver

Added in 1.0.0-alpha30

val Saver: Saver<PickerState, Any>

The default Saver implementation for PickerState.

Public constructors

PickerState

Added in 1.0.0-alpha30

PickerState(
    initialNumberOfOptions: @IntRange(from = 1) Int,
    initiallySelectedIndex: @IntRange(from = 0) Int = 0,
    shouldRepeatOptions: Boolean = true
)

Parameters
`initialNumberOfOptions: @IntRange(from = 1) Int`	the number of options.
`initiallySelectedIndex: @IntRange(from = 0) Int = 0`	the index of the option to show in the center at the start, zero-based.
`shouldRepeatOptions: Boolean = true`	if true (the default), the options will be repeated.

Public functions

animateScrollToOption

Added in 1.0.0-alpha30

suspend fun animateScrollToOption(index: Int): Unit

Animate (smooth scroll) to the given option at index.

A smooth scroll always happens to the closest item if PickerState has repeatItems=true. For example, picker values are : 0 1 2 3 0 1 2 3 0 1 2 3 Target value is 0. 0 1 2 3 >0< 1 2 3>0< 1 2 3 Picker can be scrolled forwards or backwards. To get to the target 0 it requires 1 step to scroll forwards and 3 steps to scroll backwards. Picker will be scrolled forwards as this is the closest destination.

If the distance between possible targets is the same, picker will be scrolled backwards.

import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.runtime.derivedStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.rememberCoroutineScope
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.dp
import androidx.wear.compose.material3.Button
import androidx.wear.compose.material3.Picker
import androidx.wear.compose.material3.Text
import androidx.wear.compose.material3.rememberPickerState

val coroutineScope = rememberCoroutineScope()
val state = rememberPickerState(initialNumberOfOptions = 10)
val contentDescription by remember { derivedStateOf { "${state.selectedOptionIndex + 1}" } }

Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
    Picker(
        state = state,
        spacing = 4.dp,
        contentDescription = contentDescription,
    ) {
        Button(
            onClick = { coroutineScope.launch { state.animateScrollToOption(it) } },
            label = { Text("$it") }
        )
    }
}

Parameters
`index: Int`	The index of the option to scroll to.

dispatchRawDelta

Added in 1.0.0-alpha30

open fun dispatchRawDelta(delta: Float): Float

scroll

Added in 1.0.0-alpha30

open suspend fun scroll(scrollPriority: MutatePriority, block: suspend ScrollScope.() -> Unit): Unit

scrollToOption

Added in 1.0.0-alpha30

suspend fun scrollToOption(index: Int): Unit

Instantly scroll to an option.

import androidx.compose.runtime.derivedStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.rememberCoroutineScope
import androidx.compose.ui.unit.dp
import androidx.wear.compose.material3.Button
import androidx.wear.compose.material3.Picker
import androidx.wear.compose.material3.Text
import androidx.wear.compose.material3.rememberPickerState

val coroutineScope = rememberCoroutineScope()
val state = rememberPickerState(initialNumberOfOptions = 10)
val contentDescription by remember { derivedStateOf { "${state.selectedOptionIndex + 1}" } }
Picker(
    state = state,
    spacing = 4.dp,
    contentDescription = contentDescription,
) {
    Button(
        onClick = { coroutineScope.launch { state.scrollToOption(it) } },
        label = { Text("$it") }
    )
}