| /* |
| * Copyright 2019 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package androidx.compose.material |
| |
| import androidx.compose.animation.core.Animatable |
| import androidx.compose.animation.core.TargetAnimation |
| import androidx.compose.animation.core.TweenSpec |
| import androidx.compose.animation.core.calculateTargetValue |
| import androidx.compose.animation.core.generateDecayAnimationSpec |
| import androidx.compose.foundation.Canvas |
| import androidx.compose.foundation.Interaction |
| import androidx.compose.foundation.InteractionState |
| import androidx.compose.foundation.animation.FlingConfig |
| import androidx.compose.foundation.animation.defaultFlingConfig |
| import androidx.compose.foundation.focusable |
| import androidx.compose.foundation.gestures.Orientation |
| import androidx.compose.foundation.gestures.detectTapGestures |
| import androidx.compose.foundation.gestures.draggable |
| import androidx.compose.foundation.gestures.rememberDraggableState |
| import androidx.compose.foundation.indication |
| import androidx.compose.foundation.layout.Box |
| import androidx.compose.foundation.layout.BoxWithConstraints |
| import androidx.compose.foundation.layout.Spacer |
| import androidx.compose.foundation.layout.fillMaxSize |
| import androidx.compose.foundation.layout.padding |
| import androidx.compose.foundation.layout.preferredHeightIn |
| import androidx.compose.foundation.layout.preferredSize |
| import androidx.compose.foundation.layout.preferredWidthIn |
| import androidx.compose.foundation.progressSemantics |
| import androidx.compose.foundation.shape.CircleShape |
| import androidx.compose.material.SliderDefaults.InactiveTrackColorAlpha |
| import androidx.compose.material.SliderDefaults.TickColorAlpha |
| import androidx.compose.material.ripple.rememberRipple |
| import androidx.compose.runtime.Composable |
| import androidx.compose.runtime.remember |
| import androidx.compose.runtime.rememberCoroutineScope |
| import androidx.compose.ui.Alignment |
| import androidx.compose.ui.Modifier |
| import androidx.compose.ui.geometry.Offset |
| import androidx.compose.ui.geometry.lerp |
| import androidx.compose.ui.graphics.Color |
| import androidx.compose.ui.graphics.PointMode |
| import androidx.compose.ui.graphics.StrokeCap |
| import androidx.compose.ui.input.pointer.pointerInput |
| import androidx.compose.ui.platform.LocalDensity |
| import androidx.compose.ui.platform.LocalLayoutDirection |
| import androidx.compose.ui.semantics.semantics |
| import androidx.compose.ui.semantics.setProgress |
| import androidx.compose.ui.unit.LayoutDirection |
| import androidx.compose.ui.unit.dp |
| import androidx.compose.ui.util.lerp |
| import kotlinx.coroutines.CoroutineScope |
| import kotlinx.coroutines.launch |
| import kotlin.math.abs |
| |
| /** |
| * Sliders allow users to make selections from a range of values. |
| * |
| * Sliders reflect a range of values along a bar, from which users may select a single value. |
| * They are ideal for adjusting settings such as volume, brightness, or applying image filters. |
| * |
| * Use continuous sliders allow users to make meaningful selections that don’t |
| * require a specific value: |
| * |
| * @sample androidx.compose.material.samples.SliderSample |
| * |
| * You can allow the user to choose only between predefined set of values by specifying the amount |
| * of steps between min and max values: |
| * |
| * @sample androidx.compose.material.samples.StepsSliderSample |
| * |
| * @param value current value of the Slider. If outside of [valueRange] provided, value will be |
| * coerced to this range. |
| * @param onValueChange lambda in which value should be updated |
| * @param modifier modifiers for the Slider layout |
| * @param valueRange range of values that Slider value can take. Passed [value] will be coerced to |
| * this range |
| * @param steps if greater than 0, specifies the amounts of discrete values, evenly distributed |
| * between across the whole value range. If 0, slider will behave as a continuous slider and allow |
| * to choose any value from the range specified. Must not be negative. |
| * @param onValueChangeFinished lambda to be invoked when value change has ended. This callback |
| * shouldn't be used to update the slider value (use [onValueChange] for that), but rather to |
| * know when the user has completed selecting a new value by ending a drag or a click. |
| * @param interactionState the [InteractionState] representing the different [Interaction]s |
| * present on this Slider. You can create and pass in your own remembered |
| * [InteractionState] if you want to read the [InteractionState] and customize the appearance / |
| * behavior of this Slider in different [Interaction]s. |
| * @param thumbColor color of thumb of the slider |
| * @param activeTrackColor color of the track in the part that is "active", meaning that the |
| * thumb is ahead of it |
| * @param inactiveTrackColor color of the track in the part that is "inactive", meaning that the |
| * thumb is before it |
| * @param activeTickColor colors to be used to draw tick marks on the active track, if [steps] |
| * is specified |
| * @param inactiveTickColor colors to be used to draw tick marks on the inactive track, if |
| * [steps] is specified |
| */ |
| @Composable |
| fun Slider( |
| value: Float, |
| onValueChange: (Float) -> Unit, |
| modifier: Modifier = Modifier, |
| valueRange: ClosedFloatingPointRange<Float> = 0f..1f, |
| /*@IntRange(from = 0)*/ |
| steps: Int = 0, |
| onValueChangeFinished: (() -> Unit)? = null, |
| interactionState: InteractionState = remember { InteractionState() }, |
| thumbColor: Color = MaterialTheme.colors.primary, |
| activeTrackColor: Color = MaterialTheme.colors.primary, |
| inactiveTrackColor: Color = activeTrackColor.copy(alpha = InactiveTrackColorAlpha), |
| activeTickColor: Color = MaterialTheme.colors.onPrimary.copy(alpha = TickColorAlpha), |
| inactiveTickColor: Color = activeTrackColor.copy(alpha = TickColorAlpha) |
| ) { |
| val scope = rememberCoroutineScope() |
| val position = remember(valueRange, steps, scope) { |
| SliderPosition(value, valueRange, steps, scope, onValueChange) |
| } |
| position.onValueChange = onValueChange |
| position.scaledValue = value |
| BoxWithConstraints( |
| modifier.sliderSemantics(value, position, onValueChange, valueRange, steps) |
| ) { |
| val isRtl = LocalLayoutDirection.current == LayoutDirection.Rtl |
| val maxPx = constraints.maxWidth.toFloat() |
| val minPx = 0f |
| position.setBounds(minPx, maxPx) |
| |
| val flingConfig = sliderFlingConfig(position, position.anchorsPx) |
| val gestureEndAction: (Float) -> Unit = { velocity: Float -> |
| if (flingConfig != null) { |
| scope.launch { |
| val decaySpec = flingConfig.decayAnimation.generateDecayAnimationSpec<Float>() |
| val projectedTarget = decaySpec.calculateTargetValue( |
| position.holder.value, |
| velocity |
| ) |
| val targetAnimation = flingConfig.adjustTarget(projectedTarget) |
| if (targetAnimation != null) { |
| position.holder.animateTo( |
| targetAnimation.target, |
| targetAnimation.animation, |
| initialVelocity = velocity |
| ) { |
| position.onHolderValueUpdated(this.value) |
| } |
| } else { |
| position.holder.animateDecay(velocity, decaySpec) { |
| position.onHolderValueUpdated(this.value) |
| } |
| } |
| onValueChangeFinished?.invoke() |
| } |
| } else { |
| onValueChangeFinished?.invoke() |
| } |
| } |
| |
| val press = Modifier.pointerInput(Unit) { |
| detectTapGestures( |
| onPress = { pos -> |
| position.snapTo(if (isRtl) maxPx - pos.x else pos.x) |
| interactionState.addInteraction(Interaction.Pressed, pos) |
| val success = tryAwaitRelease() |
| if (success) gestureEndAction(0f) |
| interactionState.removeInteraction(Interaction.Pressed) |
| } |
| ) |
| } |
| |
| val drag = Modifier.draggable( |
| orientation = Orientation.Horizontal, |
| reverseDirection = isRtl, |
| interactionState = interactionState, |
| onDragStopped = { velocity -> gestureEndAction(velocity) }, |
| startDragImmediately = position.holder.isRunning, |
| state = rememberDraggableState { |
| position.snapTo(position.holder.value + it) |
| } |
| ) |
| val coerced = value.coerceIn(position.startValue, position.endValue) |
| val fraction = calcFraction(position.startValue, position.endValue, coerced) |
| SliderImpl( |
| fraction, |
| position.tickFractions, |
| thumbColor, |
| activeTrackColor, |
| inactiveTrackColor, |
| activeTickColor, |
| inactiveTickColor, |
| maxPx, |
| interactionState, |
| modifier = press.then(drag) |
| ) |
| } |
| } |
| |
| /** |
| * Object to hold defaults used by [Slider] |
| */ |
| object SliderDefaults { |
| /** |
| * Default alpha of the inactive part of the track |
| */ |
| const val InactiveTrackColorAlpha = 0.24f |
| |
| /** |
| * Default alpha of the ticks that are drawn on top of the track |
| */ |
| const val TickColorAlpha = 0.54f |
| } |
| |
| @Composable |
| private fun SliderImpl( |
| positionFraction: Float, |
| tickFractions: List<Float>, |
| thumbColor: Color, |
| trackColor: Color, |
| inactiveTrackColor: Color, |
| activeTickColor: Color, |
| inactiveTickColor: Color, |
| width: Float, |
| interactionState: InteractionState, |
| modifier: Modifier |
| ) { |
| val widthDp = with(LocalDensity.current) { |
| width.toDp() |
| } |
| Box(modifier.then(DefaultSliderConstraints)) { |
| val thumbSize = ThumbRadius * 2 |
| val offset = (widthDp - thumbSize) * positionFraction |
| val center = Modifier.align(Alignment.CenterStart) |
| |
| val trackStrokeWidth: Float |
| val thumbPx: Float |
| with(LocalDensity.current) { |
| trackStrokeWidth = TrackHeight.toPx() |
| thumbPx = ThumbRadius.toPx() |
| } |
| Track( |
| center.fillMaxSize(), |
| trackColor, |
| inactiveTrackColor, |
| activeTickColor, |
| inactiveTickColor, |
| positionFraction, |
| tickFractions, |
| thumbPx, |
| trackStrokeWidth |
| ) |
| Box(center.padding(start = offset)) { |
| val elevation = if ( |
| Interaction.Pressed in interactionState || Interaction.Dragged in interactionState |
| ) { |
| ThumbPressedElevation |
| } else { |
| ThumbDefaultElevation |
| } |
| Surface( |
| shape = CircleShape, |
| color = thumbColor, |
| elevation = elevation, |
| modifier = Modifier |
| .focusable(interactionState = interactionState) |
| .indication( |
| interactionState = interactionState, |
| indication = rememberRipple( |
| bounded = false, |
| radius = ThumbRippleRadius |
| ) |
| ) |
| ) { |
| Spacer(Modifier.preferredSize(thumbSize, thumbSize)) |
| } |
| } |
| } |
| } |
| |
| @Composable |
| private fun Track( |
| modifier: Modifier, |
| color: Color, |
| inactiveColor: Color, |
| activeTickColor: Color, |
| inactiveTickColor: Color, |
| positionFraction: Float, |
| tickFractions: List<Float>, |
| thumbPx: Float, |
| trackStrokeWidth: Float |
| ) { |
| Canvas(modifier) { |
| val isRtl = layoutDirection == LayoutDirection.Rtl |
| val sliderLeft = Offset(thumbPx, center.y) |
| val sliderRight = Offset(size.width - thumbPx, center.y) |
| val sliderStart = if (isRtl) sliderRight else sliderLeft |
| val sliderEnd = if (isRtl) sliderLeft else sliderRight |
| drawLine( |
| inactiveColor, |
| sliderStart, |
| sliderEnd, |
| trackStrokeWidth, |
| StrokeCap.Round |
| ) |
| val sliderValue = Offset( |
| sliderStart.x + (sliderEnd.x - sliderStart.x) * positionFraction, |
| center.y |
| ) |
| |
| drawLine(color, sliderStart, sliderValue, trackStrokeWidth, StrokeCap.Round) |
| tickFractions.groupBy { it > positionFraction }.forEach { (afterFraction, list) -> |
| drawPoints( |
| list.map { |
| Offset(lerp(sliderStart, sliderEnd, it).x, center.y) |
| }, |
| PointMode.Points, |
| if (afterFraction) inactiveTickColor else activeTickColor, |
| trackStrokeWidth, |
| StrokeCap.Round |
| ) |
| } |
| } |
| } |
| |
| // Scale x1 from a1..b1 range to a2..b2 range |
| private fun scale(a1: Float, b1: Float, x1: Float, a2: Float, b2: Float) = |
| lerp(a2, b2, calcFraction(a1, b1, x1)) |
| |
| // Calculate the 0..1 fraction that `pos` value represents between `a` and `b` |
| private fun calcFraction(a: Float, b: Float, pos: Float) = |
| (if (b - a == 0f) 0f else (pos - a) / (b - a)).coerceIn(0f, 1f) |
| |
| @Composable |
| private fun sliderFlingConfig( |
| value: SliderPosition, |
| anchors: List<Float> |
| ): FlingConfig? { |
| return if (anchors.isEmpty()) { |
| null |
| } else { |
| val adjustTarget: (Float) -> TargetAnimation? = { _ -> |
| val now = value.holder.value |
| val point = anchors.minByOrNull { abs(it - now) } |
| val adjusted = point ?: now |
| TargetAnimation(adjusted, SliderToTickAnimation) |
| } |
| defaultFlingConfig(adjustTarget = adjustTarget) |
| } |
| } |
| |
| private fun Modifier.sliderSemantics( |
| value: Float, |
| position: SliderPosition, |
| onValueChange: (Float) -> Unit, |
| valueRange: ClosedFloatingPointRange<Float> = 0f..1f, |
| steps: Int = 0 |
| ): Modifier { |
| val coerced = value.coerceIn(position.startValue, position.endValue) |
| return semantics(mergeDescendants = true) { |
| setProgress( |
| action = { targetValue -> |
| val newValue = targetValue.coerceIn(position.startValue, position.endValue) |
| val resolvedValue = if (steps > 0) { |
| position.tickFractions |
| .map { lerp(position.startValue, position.endValue, it) } |
| .minByOrNull { abs(it - newValue) } ?: newValue |
| } else { |
| newValue |
| } |
| // This is to keep it consistent with AbsSeekbar.java: return false if no |
| // change from current. |
| if (resolvedValue == coerced) { |
| false |
| } else { |
| onValueChange(resolvedValue) |
| true |
| } |
| } |
| ) |
| }.progressSemantics(value, valueRange, steps) |
| } |
| |
| /** |
| * Internal state for [Slider] that represents the Slider value, its bounds and optional amount of |
| * steps evenly distributed across the Slider range. |
| * |
| * @param initial initial value for the Slider when created. If outside of range provided, |
| * initial position will be coerced to this range |
| * @param valueRange range of values that Slider value can take |
| * @param steps if greater than 0, specifies the amounts of discrete values, evenly distributed |
| * between across the whole value range. If 0, slider will behave as a continuous slider and allow |
| * to choose any value from the range specified. Must not be negative. |
| */ |
| private class SliderPosition( |
| initial: Float = 0f, |
| val valueRange: ClosedFloatingPointRange<Float> = 0f..1f, |
| /*@IntRange(from = 0)*/ |
| steps: Int = 0, |
| val scope: CoroutineScope, |
| var onValueChange: (Float) -> Unit |
| ) { |
| |
| internal val startValue: Float = valueRange.start |
| internal val endValue: Float = valueRange.endInclusive |
| |
| init { |
| require(steps >= 0) { |
| "steps should be >= 0" |
| } |
| } |
| |
| internal var scaledValue: Float = initial |
| set(value) { |
| val scaled = scale(startValue, endValue, value, startPx, endPx) |
| // floating point error due to rescaling |
| if ((scaled - holder.value) > floatPointMistakeCorrection) { |
| snapTo(scaled) |
| } |
| } |
| |
| private val floatPointMistakeCorrection = (valueRange.endInclusive - valueRange.start) / 100 |
| |
| private var endPx = Float.MAX_VALUE |
| private var startPx = Float.MIN_VALUE |
| |
| internal fun setBounds(min: Float, max: Float) { |
| if (startPx == min && endPx == max) return |
| val newValue = scale(startPx, endPx, holder.value, min, max) |
| startPx = min |
| endPx = max |
| holder.updateBounds(min, max) |
| anchorsPx = tickFractions.map { |
| lerp(startPx, endPx, it) |
| } |
| snapTo(newValue) |
| } |
| |
| internal val tickFractions: List<Float> = |
| if (steps == 0) emptyList() else List(steps + 2) { it.toFloat() / (steps + 1) } |
| |
| internal var anchorsPx: List<Float> = emptyList() |
| private set |
| |
| internal val holder = Animatable(scale(startValue, endValue, initial, startPx, endPx)) |
| |
| internal fun snapTo(newValue: Float) { |
| scope.launch { |
| holder.snapTo(newValue) |
| onHolderValueUpdated(holder.value) |
| } |
| } |
| |
| internal val onHolderValueUpdated: (value: Float) -> Unit = { |
| onValueChange(scale(startPx, endPx, it, startValue, endValue)) |
| } |
| } |
| |
| // Internal to be referred to in tests |
| internal val ThumbRadius = 10.dp |
| private val ThumbRippleRadius = 24.dp |
| private val ThumbDefaultElevation = 1.dp |
| private val ThumbPressedElevation = 6.dp |
| |
| // Internal to be referred to in tests |
| internal val TrackHeight = 4.dp |
| private val SliderHeight = 48.dp |
| private val SliderMinWidth = 144.dp // TODO: clarify min width |
| private val DefaultSliderConstraints = |
| Modifier.preferredWidthIn(min = SliderMinWidth) |
| .preferredHeightIn(max = SliderHeight) |
| |
| private val SliderToTickAnimation = TweenSpec<Float>(durationMillis = 100) |