当Tab宽度大于90.dp时，您可以更改它，因为在源代码中，它是使用最小值为90.dp的Cosntraints测量的

private val ScrollableTabRowMinimumTabWidth = 90.dp

在子合成版面中

@Composable
@UiComposable
fun ScrollableTabRow(
    selectedTabIndex: Int,
    modifier: Modifier = Modifier,
    backgroundColor: Color = MaterialTheme.colors.primarySurface,
    contentColor: Color = contentColorFor(backgroundColor),
    edgePadding: Dp = TabRowDefaults.ScrollableTabRowPadding,
    indicator: @Composable @UiComposable
        (tabPositions: List<TabPosition>) -> Unit = @Composable { tabPositions ->
            TabRowDefaults.Indicator(
                Modifier.tabIndicatorOffset(tabPositions[selectedTabIndex])
            )
        },
    divider: @Composable @UiComposable () -> Unit =
        @Composable {
            TabRowDefaults.Divider()
        },
    tabs: @Composable @UiComposable () -> Unit
) {
    Surface(
        modifier = modifier,
        color = backgroundColor,
        contentColor = contentColor
    ) {
        val scrollState = rememberScrollState()
        val coroutineScope = rememberCoroutineScope()
        val scrollableTabData = remember(scrollState, coroutineScope) {
            ScrollableTabData(
                scrollState = scrollState,
                coroutineScope = coroutineScope
            )
        }
        SubcomposeLayout(
            Modifier.fillMaxWidth()
                .wrapContentSize(align = Alignment.CenterStart)
                .horizontalScroll(scrollState)
                .selectableGroup()
                .clipToBounds()
        ) { constraints ->
            val minTabWidth = ScrollableTabRowMinimumTabWidth.roundToPx()
            val padding = edgePadding.roundToPx()

           // 🔥🔥 This is the minimum size it's measured with
            val tabConstraints = constraints.copy(minWidth = minTabWidth)

            val tabPlaceables = subcompose(TabSlots.Tabs, tabs)
                .map { it.measure(tabConstraints) }

            var layoutWidth = padding * 2
            var layoutHeight = 0
            tabPlaceables.forEach {
                layoutWidth += it.width
                layoutHeight = maxOf(layoutHeight, it.height)
            }

            // Position the children.
            layout(layoutWidth, layoutHeight) {
                // Place the tabs
                val tabPositions = mutableListOf<TabPosition>()
                var left = padding
                tabPlaceables.forEach {
                    it.placeRelative(left, 0)
                    tabPositions.add(TabPosition(left = left.toDp(), width = it.width.toDp()))
                    left += it.width
                }

                // The divider is measured with its own height, and width equal to the total width
                // of the tab row, and then placed on top of the tabs.
                subcompose(TabSlots.Divider, divider).forEach {
                    val placeable = it.measure(
                        constraints.copy(
                            minHeight = 0,
                            minWidth = layoutWidth,
                            maxWidth = layoutWidth
                        )
                    )
                    placeable.placeRelative(0, layoutHeight - placeable.height)
                }

                // The indicator container is measured to fill the entire space occupied by the tab
                // row, and then placed on top of the divider.
                subcompose(TabSlots.Indicator) {
                    indicator(tabPositions)
                }.forEach {
                    it.measure(Constraints.fixed(layoutWidth, layoutHeight)).placeRelative(0, 0)
                }

                scrollableTabData.onLaidOut(
                    density = this@SubcomposeLayout,
                    edgeOffset = padding,
                    tabPositions = tabPositions,
                    selectedTab = selectedTabIndex
                )
            }
        }
    }
}

如果复制粘贴源代码并将minimumTabWidth更改为0，则可以指定任何宽度修饰符

/**
 * <a href="https://material.io/components/tabs#scrollable-tabs" class="external" target="_blank">Material Design scrollable tabs</a>.
 *
 * When a set of tabs cannot fit on screen, use scrollable tabs. Scrollable tabs can use longer text
 * labels and a larger number of tabs. They are best used for browsing on touch interfaces.
 *
 * ![Scrollable tabs image](https://developer.android.com/images/reference/androidx/compose/material/scrollable-tabs.png)
 *
 * A ScrollableTabRow contains a row of [Tab]s, and displays an indicator underneath the currently
 * selected tab. A ScrollableTabRow places its tabs offset from the starting edge, and allows
 * scrolling to tabs that are placed off screen. For a fixed tab row that does not allow
 * scrolling, and evenly places its tabs, see [TabRow].
 *
 * @param selectedTabIndex the index of the currently selected tab
 * @param modifier optional [Modifier] for this ScrollableTabRow
 * @param backgroundColor The background color for the ScrollableTabRow. Use [Color.Transparent] to
 * have no color.
 * @param contentColor The preferred content color provided by this ScrollableTabRow to its
 * children. Defaults to either the matching content color for [backgroundColor], or if
 * [backgroundColor] is not a color from the theme, this will keep the same value set above this
 * ScrollableTabRow.
 * @param edgePadding the padding between the starting and ending edge of ScrollableTabRow, and
 * the tabs inside the ScrollableTabRow. This padding helps inform the user that this tab row can
 * be scrolled, unlike a [TabRow].
 * @param indicator the indicator that represents which tab is currently selected. By default this
 * will be a [TabRowDefaults.Indicator], using a [TabRowDefaults.tabIndicatorOffset]
 * modifier to animate its position. Note that this indicator will be forced to fill up the
 * entire ScrollableTabRow, so you should use [TabRowDefaults.tabIndicatorOffset] or similar to
 * animate the actual drawn indicator inside this space, and provide an offset from the start.
 * @param divider the divider displayed at the bottom of the ScrollableTabRow. This provides a layer
 * of separation between the ScrollableTabRow and the content displayed underneath.
 * @param tabs the tabs inside this ScrollableTabRow. Typically this will be multiple [Tab]s. Each
 * element inside this lambda will be measured and placed evenly across the TabRow, each taking
 * up equal space.
 */
@Composable
@UiComposable
fun MyScrollableTabRow(
    selectedTabIndex: Int,
    modifier: Modifier = Modifier,
    backgroundColor: Color = MaterialTheme.colors.primarySurface,
    contentColor: Color = contentColorFor(backgroundColor),
    edgePadding: Dp = TabRowDefaults.ScrollableTabRowPadding,
    indicator: @Composable @UiComposable
        (tabPositions: List<TabPosition>) -> Unit = @Composable { tabPositions ->
        TabRowDefaults.Indicator(
            Modifier.tabIndicatorOffset(tabPositions[selectedTabIndex])
        )
    },
    divider: @Composable @UiComposable () -> Unit =
        @Composable {
            TabRowDefaults.Divider()
        },
    tabs: @Composable @UiComposable () -> Unit
) {
    Surface(
        modifier = modifier,
        color = backgroundColor,
        contentColor = contentColor
    ) {
        val scrollState = rememberScrollState()
        val coroutineScope = rememberCoroutineScope()
        val scrollableTabData = remember(scrollState, coroutineScope) {
            ScrollableTabData(
                scrollState = scrollState,
                coroutineScope = coroutineScope
            )
        }
        SubcomposeLayout(
            Modifier.fillMaxWidth()
                .wrapContentSize(align = Alignment.CenterStart)
                .horizontalScroll(scrollState)
                .selectableGroup()
                .clipToBounds()
        ) { constraints ->
            val minTabWidth = ScrollableTabRowMinimumTabWidth.roundToPx()
            val padding = edgePadding.roundToPx()
            val tabConstraints = constraints.copy(minWidth = 0)

            val tabPlaceables = subcompose(TabSlots.Tabs, tabs)
                .map { it.measure(tabConstraints) }

            var layoutWidth = padding * 2
            var layoutHeight = 0
            tabPlaceables.forEach {
                layoutWidth += it.width
                layoutHeight = maxOf(layoutHeight, it.height)
            }

            // Position the children.
            layout(layoutWidth, layoutHeight) {
                // Place the tabs
                val tabPositions = mutableListOf<TabPosition>()
                var left = padding
                tabPlaceables.forEach {
                    it.placeRelative(left, 0)
                    tabPositions.add(TabPosition(left = left.toDp(), width = it.width.toDp()))
                    left += it.width
                }

                // The divider is measured with its own height, and width equal to the total width
                // of the tab row, and then placed on top of the tabs.
                subcompose(TabSlots.Divider, divider).forEach {
                    val placeable = it.measure(
                        constraints.copy(
                            minHeight = 0,
                            minWidth = layoutWidth,
                            maxWidth = layoutWidth
                        )
                    )
                    placeable.placeRelative(0, layoutHeight - placeable.height)
                }

                // The indicator container is measured to fill the entire space occupied by the tab
                // row, and then placed on top of the divider.
                subcompose(TabSlots.Indicator) {
                    indicator(tabPositions)
                }.forEach {
                    it.measure(Constraints.fixed(layoutWidth, layoutHeight)).placeRelative(0, 0)
                }

                scrollableTabData.onLaidOut(
                    density = this@SubcomposeLayout,
                    edgeOffset = padding,
                    tabPositions = tabPositions,
                    selectedTab = selectedTabIndex
                )
            }
        }
    }
}

/**
 * Data class that contains information about a tab's position on screen, used for calculating
 * where to place the indicator that shows which tab is selected.
 *
 * @property left the left edge's x position from the start of the [TabRow]
 * @property right the right edge's x position from the start of the [TabRow]
 * @property width the width of this tab
 */
@Immutable
class TabPosition internal constructor(val left: Dp, val width: Dp) {
    val right: Dp get() = left + width

    override fun equals(other: Any?): Boolean {
        if (this === other) return true
        if (other !is TabPosition) return false

        if (left != other.left) return false
        if (width != other.width) return false

        return true
    }

    override fun hashCode(): Int {
        var result = left.hashCode()
        result = 31 * result + width.hashCode()
        return result
    }

    override fun toString(): String {
        return "TabPosition(left=$left, right=$right, width=$width)"
    }
}

/**
 * Contains default implementations and values used for TabRow.
 */
object TabRowDefaults {
    /**
     * Default [Divider], which will be positioned at the bottom of the [TabRow], underneath the
     * indicator.
     *
     * @param modifier modifier for the divider's layout
     * @param thickness thickness of the divider
     * @param color color of the divider
     */
    @Composable
    fun Divider(
        modifier: Modifier = Modifier,
        thickness: Dp = DividerThickness,
        color: Color = LocalContentColor.current.copy(alpha = DividerOpacity)
    ) {
        androidx.compose.material.Divider(modifier = modifier, thickness = thickness, color = color)
    }

    /**
     * Default indicator, which will be positioned at the bottom of the [TabRow], on top of the
     * divider.
     *
     * @param modifier modifier for the indicator's layout
     * @param height height of the indicator
     * @param color color of the indicator
     */
    @Composable
    fun Indicator(
        modifier: Modifier = Modifier,
        height: Dp = IndicatorHeight,
        color: Color = LocalContentColor.current
    ) {
        Box(
            modifier
                .fillMaxWidth()
                .height(height)
                .background(color = color)
        )
    }

    /**
     * [Modifier] that takes up all the available width inside the [TabRow], and then animates
     * the offset of the indicator it is applied to, depending on the [currentTabPosition].
     *
     * @param currentTabPosition [TabPosition] of the currently selected tab. This is used to
     * calculate the offset of the indicator this modifier is applied to, as well as its width.
     */
    fun Modifier.tabIndicatorOffset(
        currentTabPosition: TabPosition
    ): Modifier = composed(
        inspectorInfo = debugInspectorInfo {
            name = "tabIndicatorOffset"
            value = currentTabPosition
        }
    ) {
        val currentTabWidth by animateDpAsState(
            targetValue = currentTabPosition.width,
            animationSpec = tween(durationMillis = 250, easing = FastOutSlowInEasing)
        )
        val indicatorOffset by animateDpAsState(
            targetValue = currentTabPosition.left,
            animationSpec = tween(durationMillis = 250, easing = FastOutSlowInEasing)
        )
        fillMaxWidth()
            .wrapContentSize(Alignment.BottomStart)
            .offset(x = indicatorOffset)
            .width(currentTabWidth)
    }

    /**
     * Default opacity for the color of [Divider]
     */
    const val DividerOpacity = 0.12f

    /**
     * Default thickness for [Divider]
     */
    val DividerThickness = 1.dp

    /**
     * Default height for [Indicator]
     */
    val IndicatorHeight = 2.dp

    /**
     * The default padding from the starting edge before a tab in a [ScrollableTabRow].
     */
    val ScrollableTabRowPadding = 52.dp
}

private enum class TabSlots {
    Tabs,
    Divider,
    Indicator
}

/**
 * Class holding onto state needed for [ScrollableTabRow]
 */
private class ScrollableTabData(
    private val scrollState: ScrollState,
    private val coroutineScope: CoroutineScope
) {
    private var selectedTab: Int? = null

    fun onLaidOut(
        density: Density,
        edgeOffset: Int,
        tabPositions: List<TabPosition>,
        selectedTab: Int
    ) {
        // Animate if the new tab is different from the old tab, or this is called for the first
        // time (i.e selectedTab is `null`).
        if (this.selectedTab != selectedTab) {
            this.selectedTab = selectedTab
            tabPositions.getOrNull(selectedTab)?.let {
                // Scrolls to the tab with [tabPosition], trying to place it in the center of the
                // screen or as close to the center as possible.
                val calculatedOffset = it.calculateTabOffset(density, edgeOffset, tabPositions)
                if (scrollState.value != calculatedOffset) {
                    coroutineScope.launch {
                        scrollState.animateScrollTo(
                            calculatedOffset,
                            animationSpec = ScrollableTabRowScrollSpec
                        )
                    }
                }
            }
        }
    }

    /**
     * @return the offset required to horizontally center the tab inside this TabRow.
     * If the tab is at the start / end, and there is not enough space to fully centre the tab, this
     * will just clamp to the min / max position given the max width.
     */
    private fun TabPosition.calculateTabOffset(
        density: Density,
        edgeOffset: Int,
        tabPositions: List<TabPosition>
    ): Int = with(density) {
        val totalTabRowWidth = tabPositions.last().right.roundToPx() + edgeOffset
        val visibleWidth = totalTabRowWidth - scrollState.maxValue
        val tabOffset = left.roundToPx()
        val scrollerCenter = visibleWidth / 2
        val tabWidth = width.roundToPx()
        val centeredTabOffset = tabOffset - (scrollerCenter - tabWidth / 2)
        // How much space we have to scroll. If the visible width is <= to the total width, then
        // we have no space to scroll as everything is always visible.
        val availableSpace = (totalTabRowWidth - visibleWidth).coerceAtLeast(0)
        return centeredTabOffset.coerceIn(0, availableSpace)
    }
}

private val ScrollableTabRowMinimumTabWidth = 90.dp

/**
 * [AnimationSpec] used when scrolling to a tab that is not fully visible.
 */
private val ScrollableTabRowScrollSpec: AnimationSpec<Float> = tween(
    durationMillis = 250,
    easing = FastOutSlowInEasing
)