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Desktop components

What is covered

In this tutorial, we will show you how to use desktop-specific components of Compose for Desktop such as scrollbars and tooltips.

Scrollbars

You can apply scrollbars to scrollable components. The scrollbar and scrollable components share a common state to synchronize with each other. For example, VerticalScrollbar can be attached to Modifier.verticalScroll, and LazyColumnFor and HorizontalScrollbar can be attached to Modifier.horizontalScroll and LazyRowFor.

import androidx.compose.desktop.Window
import androidx.compose.foundation.HorizontalScrollbar
import androidx.compose.foundation.VerticalScrollbar
import androidx.compose.foundation.background
import androidx.compose.foundation.horizontalScroll
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.Spacer
import androidx.compose.foundation.layout.fillMaxHeight
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.height
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.width
import androidx.compose.foundation.rememberScrollState
import androidx.compose.foundation.rememberScrollbarAdapter
import androidx.compose.foundation.verticalScroll
import androidx.compose.material.Text
import androidx.compose.runtime.Composable
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.unit.IntSize
import androidx.compose.ui.unit.dp

fun main() {
    Window(title = "Scrollbars", size = IntSize(250, 400)) {
        Box(
            modifier = Modifier.fillMaxSize()
                .background(color = Color(180, 180, 180))
                .padding(10.dp)
        ) {
            val stateVertical = rememberScrollState(0)
            val stateHorizontal = rememberScrollState(0)

            Box(
                modifier = Modifier
                    .fillMaxSize()
                    .verticalScroll(stateVertical)
                    .padding(end = 12.dp, bottom = 12.dp)
                    .horizontalScroll(stateHorizontal)
            ) {
                Column {
                    for (item in 0..30) {
                        TextBox("Item #$item")
                        if (item < 30) {
                            Spacer(modifier = Modifier.height(5.dp))
                        }
                    }
                }
            }
            VerticalScrollbar(
                modifier = Modifier.align(Alignment.CenterEnd)
                    .fillMaxHeight(),
                adapter = rememberScrollbarAdapter(stateVertical)
            )
            HorizontalScrollbar(
                modifier = Modifier.align(Alignment.BottomStart)
                    .fillMaxWidth()
                    .padding(end = 12.dp),
                adapter = rememberScrollbarAdapter(stateHorizontal)
            )
        }
    }
}

@Composable
fun TextBox(text: String = "Item") {
    Box(
        modifier = Modifier.height(32.dp)
            .width(400.dp)
            .background(color = Color(200, 0, 0, 20))
            .padding(start = 10.dp),
        contentAlignment = Alignment.CenterStart
    ) {
        Text(text = text)
    }
}

Lazy scrollable components with Scrollbar

You can use scrollbars with lazy scrollable components, for example, LazyColumn.

import androidx.compose.desktop.Window
import androidx.compose.foundation.VerticalScrollbar
import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Spacer
import androidx.compose.foundation.layout.fillMaxHeight
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.height
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.lazy.rememberLazyListState
import androidx.compose.foundation.rememberScrollbarAdapter
import androidx.compose.material.Text
import androidx.compose.runtime.Composable
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.unit.IntSize
import androidx.compose.ui.unit.dp

fun main() {
    Window(title = "Scrollbars", size = IntSize(250, 400)) {
        LazyScrollable()
    }
}

@Composable
fun LazyScrollable() {
    Box(
        modifier = Modifier.fillMaxSize()
            .background(color = Color(180, 180, 180))
            .padding(10.dp)
    ) {

        val state = rememberLazyListState()

        LazyColumn(Modifier.fillMaxSize().padding(end = 12.dp), state) {
            items(1000) { x ->
                TextBox("Item #$x")
                Spacer(modifier = Modifier.height(5.dp))
            }
        }
        VerticalScrollbar(
            modifier = Modifier.align(Alignment.CenterEnd).fillMaxHeight(),
            adapter = rememberScrollbarAdapter(
                scrollState = state
            )
        )
    }
}

@Composable
fun TextBox(text: String = "Item") {
    Box(
        modifier = Modifier.height(32.dp)
            .fillMaxWidth()
            .background(color = Color(0, 0, 0, 20))
            .padding(start = 10.dp),
        contentAlignment = Alignment.CenterStart
    ) {
        Text(text = text)
    }
}

Theme applying

Scrollbars support themes to change their appearance. The example below shows how to use the DesktopTheme appearance for the scrollbar.

import androidx.compose.desktop.DesktopTheme
import androidx.compose.desktop.Window
import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.fillMaxHeight
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.height
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.Spacer
import androidx.compose.foundation.rememberScrollbarAdapter
import androidx.compose.foundation.rememberScrollState
import androidx.compose.material.Text
import androidx.compose.foundation.VerticalScrollbar
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.verticalScroll
import androidx.compose.material.MaterialTheme
import androidx.compose.runtime.Composable
import androidx.compose.ui.Alignment
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.IntSize

fun main() {
    Window(title = "Scrollbars", size = IntSize(280, 400)) {
        MaterialTheme {
            DesktopTheme {
                Box(
                    modifier = Modifier.fillMaxSize()
                        .background(color = Color(180, 180, 180))
                        .padding(10.dp)
                ) {
                    val state = rememberScrollState(0)

                    Column(
                        modifier = Modifier
                            .verticalScroll(state)
                            .fillMaxSize()
                            .padding(end = 12.dp)
                    ) {
                        for (item in 0..30) {
                            TextBox("Item #$item")
                            if (item < 30) {
                                Spacer(modifier = Modifier.height(5.dp))
                            }
                        }
                    }
                    VerticalScrollbar(
                        modifier = Modifier.align(Alignment.CenterEnd)
                            .fillMaxHeight(),
                        adapter = rememberScrollbarAdapter(state)
                    )
                }
            }
        }
    }
}

@Composable
fun TextBox(text: String = "Item") {
    Box(
        modifier = Modifier.height(32.dp)
            .fillMaxWidth()
            .background(color = Color(0, 0, 0, 20))
            .padding(start = 10.dp),
        contentAlignment = Alignment.CenterStart
    ) {
        Text(text = text)
    }
}

Tooltips

You can add tooltip to any components using BoxWithTooltip. Basically BoxWithTooltip is a Box with the ability to show a tooltip, and has the same arguments and behavior as Box. The main arguments of the BoxWithTooltip function:

tooltip - composable content representing tooltip
delay - time delay in milliseconds after which the tooltip will be shown (default is 500 ms)
offset - tooltip offset, the default position of the tooltip is under the mouse cursor

import androidx.compose.desktop.Window
import androidx.compose.foundation.BoxWithTooltip
import androidx.compose.foundation.TooltipPlacement
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.material.Button
import androidx.compose.material.Surface
import androidx.compose.material.Text
import androidx.compose.ui.Alignment
import androidx.compose.ui.draw.shadow
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.DpOffset
import androidx.compose.ui.unit.IntSize

fun main() = Window(title = "Tooltip Example", size = IntSize(300, 300)) {
    val buttons = listOf("Button A", "Button B", "Button C", "Button D", "Button E", "Button F")
    Column(Modifier.fillMaxSize(), Arrangement.spacedBy(5.dp)) {
        buttons.forEachIndexed { index, name ->
            // wrap button in BoxWithTooltip
            BoxWithTooltip(
                modifier = Modifier.padding(start = 40.dp),
                tooltip = {
                    // composable tooltip content
                    Surface(
                        modifier = Modifier.shadow(4.dp),
                        color = Color(255, 255, 210),
                        shape = RoundedCornerShape(4.dp)
                    ) {
                        Text(
                            text = "Tooltip for ${name}",
                            modifier = Modifier.padding(10.dp)
                        )
                    }
                },
                delay = 600, // in milliseconds
                tooltipPlacement = TooltipPlacement(
                    anchor = TooltipPlacement.Anchor.Pointer,
                    alignment = Alignment.BottomEnd,
                    offset = if (index % 2 == 0) DpOffset(-16.dp, 0.dp) else DpOffset.Zero // tooltip offset
                )
            ) {
                Button(onClick = {}) { Text(text = name) }
            }
        }
    }
}

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