Jetpack Compose Reducing internal padding of Tabs

Question

I want to reduce padding of a single tab. Following image shows what I want:

What I am getting:

I am currently using the "accompanist-pager" and "accompanist-pager-indicators" with version 0.16.0.

Code:

@Composable
fun Tabs(tabNames: List<String>, pagerState: PagerState, scrollToPage: (Int) -> Unit) {
  TabRow(
    selectedTabIndex = pagerState.currentPage,
    backgroundColor = Color.White,
    contentColor = Color.Black,
    divider = {
      TabRowDefaults.Divider(
        thickness = 4.dp
      )
    },
    indicator = { tabPositions ->
      TabRowDefaults.Indicator(
        modifier = Modifier.customTabIndicatorOffset(tabPositions[pagerState.currentPage]),
        height = 4.dp,
        color = EmeraldTheme.colors.primary
      )
    }
  ) {
    tabNames.forEachIndexed { index, name ->
      Tab(
        text = {
          Text(
            text = name,
            maxLines = 1,
            style = globalSearchDefaultTextStyle,
            fontWeight = if (pagerState.currentPage == index) FontWeight.Bold else FontWeight.Normal,
            color = if (pagerState.currentPage == index) EmeraldColor.Black100 else colorResource(globalSearchR.color.darkGrey20),
          )
        },
        selected = pagerState.currentPage == index,
        onClick = {
          scrollToPage(index)
        }
      )
    }
    Row { Spacer(Modifier.weight(1f, true)) }
  }
}

Answer 1

With the current version of TabRow (or ScrollableTabRow) you will not be able to do it. You will need to create your own TabRow composable.

Also, you should probably use a ScrollableTabRow instead of TabRow because TabRow evenly distributes the entire available width for its Tabs. So the content padding for that doesn't matter that much.

You can pretty much copy-paste the entire code for ScrollableTabRow, but modify the bit that sets up the tabConstraints.

It should no longer use the minTabWidth:

val minTabWidth = ScrollableTabRowMinimumTabWidth.roundToPx()

Answer 2

Custom tab is the way to go.

import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.height
import androidx.compose.foundation.layout.size
import androidx.compose.material.Tab
import androidx.compose.material.Text

Tab(selected, onClick) {
    Column(
        Modifier.padding(10.dp).height(50.dp).fillMaxWidth(),
        verticalArrangement = Arrangement.SpaceBetween
    ) {
        Box(
            Modifier.size(10.dp)
                .align(Alignment.CenterHorizontally)
                .background(color = if (selected) Color.Red else Color.White)
        )
        Text(
            text = title,
            style = MaterialTheme.typography.body1,
            modifier = Modifier.align(Alignment.CenterHorizontally)
        )
    }
}

https://developer.android.com/reference/kotlin/androidx/compose/material/package-summary#Tab(kotlin.Boolean,kotlin.Function0,androidx.compose.ui.Modifier,kotlin.Boolean,androidx.compose.foundation.interaction.MutableInteractionSource,androidx.compose.ui.graphics.Color,androidx.compose.ui.graphics.Color,kotlin.Function1)

Answer 3

You can use java reflection to change the value of ScrollableTabRowMinimumTabWidth. And you can upvote here -> https://issuetracker.google.com/issues/226665301

try {
    Class
        .forName("androidx.compose.material3.TabRowKt")
        .getDeclaredField("ScrollableTabRowMinimumTabWidth").apply {
            isAccessible = true
        }.set(this, 0f)
} catch (e: Exception) {
    e.printStackTrace()
}

Answer 4

A quick way you can solve this setting a fixed width in the Modifier