| /* |
| * 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.ui.material |
| |
| import androidx.compose.animation.core.AnimatedFloat |
| import androidx.compose.animation.core.AnimationClockObservable |
| import androidx.compose.animation.core.AnimationEndReason |
| import androidx.compose.animation.core.TargetAnimation |
| import androidx.compose.animation.core.TweenSpec |
| import androidx.compose.Composable |
| import androidx.compose.remember |
| import androidx.compose.animation.asDisposableClock |
| import androidx.ui.core.Alignment |
| import androidx.ui.core.AnimationClockAmbient |
| import androidx.ui.core.DensityAmbient |
| import androidx.ui.core.LayoutDirection |
| import androidx.ui.core.Modifier |
| import androidx.ui.core.WithConstraints |
| import androidx.ui.core.gesture.pressIndicatorGestureFilter |
| import androidx.ui.core.gesture.scrollorientationlocking.Orientation |
| import androidx.ui.core.semantics.semantics |
| import androidx.compose.foundation.Box |
| import androidx.compose.foundation.Canvas |
| import androidx.compose.foundation.Interaction |
| import androidx.compose.foundation.InteractionState |
| import androidx.compose.foundation.Strings |
| import androidx.compose.foundation.animation.FlingConfig |
| import androidx.compose.foundation.animation.fling |
| import androidx.compose.foundation.animation.defaultFlingConfig |
| import androidx.compose.foundation.gestures.draggable |
| import androidx.compose.foundation.indication |
| import androidx.compose.foundation.shape.corner.CircleShape |
| import androidx.ui.geometry.Offset |
| import androidx.ui.geometry.lerp |
| import androidx.ui.graphics.Color |
| import androidx.ui.graphics.PointMode |
| import androidx.ui.graphics.StrokeCap |
| import androidx.compose.foundation.layout.Spacer |
| import androidx.compose.foundation.layout.Stack |
| 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.ui.material.ripple.RippleIndication |
| import androidx.ui.semantics.AccessibilityRangeInfo |
| import androidx.ui.semantics.accessibilityValue |
| import androidx.ui.semantics.accessibilityValueRange |
| import androidx.ui.semantics.scrollBackward |
| import androidx.ui.semantics.scrollForward |
| import androidx.ui.semantics.setProgress |
| import androidx.ui.unit.dp |
| import androidx.ui.util.format |
| import androidx.ui.util.lerp |
| import androidx.ui.util.annotation.IntRange |
| import kotlin.math.abs |
| import kotlin.math.roundToInt |
| |
| /** |
| * 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.ui.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.ui.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 |
| * @param onValueChangeEnd 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 color color of the Slider |
| */ |
| @Composable |
| fun Slider( |
| value: Float, |
| onValueChange: (Float) -> Unit, |
| modifier: Modifier = Modifier, |
| valueRange: ClosedFloatingPointRange<Float> = 0f..1f, |
| @IntRange(from = 0) steps: Int = 0, |
| onValueChangeEnd: () -> Unit = {}, |
| color: Color = MaterialTheme.colors.primary |
| ) { |
| val clock = AnimationClockAmbient.current.asDisposableClock() |
| val position = remember(valueRange, steps) { |
| SliderPosition(value, valueRange, steps, clock, onValueChange) |
| } |
| position.onValueChange = onValueChange |
| position.scaledValue = value |
| WithConstraints(modifier.sliderSemantics(value, position, onValueChange, valueRange, steps)) { |
| val isRtl = layoutDirection == LayoutDirection.Rtl |
| val maxPx = constraints.maxWidth.toFloat() |
| val minPx = 0f |
| position.setBounds(minPx, maxPx) |
| |
| val flingConfig = SliderFlingConfig(position, position.anchorsPx) |
| val gestureEndAction = { velocity: Float -> |
| if (flingConfig != null) { |
| position.holder.fling(velocity, flingConfig) { reason, endValue, _ -> |
| if (reason != AnimationEndReason.Interrupted) { |
| position.holder.snapTo(endValue) |
| onValueChangeEnd() |
| } |
| } |
| } else { |
| onValueChangeEnd() |
| } |
| } |
| |
| val interactionState = remember { InteractionState() } |
| |
| val press = Modifier.pressIndicatorGestureFilter( |
| onStart = { pos -> |
| position.holder.snapTo(if (isRtl) maxPx - pos.x else pos.x) |
| interactionState.addInteraction(Interaction.Pressed, pos) |
| }, |
| onStop = { |
| gestureEndAction(0f) |
| interactionState.removeInteraction(Interaction.Pressed) |
| }, |
| onCancel = { |
| interactionState.removeInteraction(Interaction.Pressed) |
| } |
| ) |
| |
| val drag = Modifier.draggable( |
| orientation = Orientation.Horizontal, |
| reverseDirection = isRtl, |
| interactionState = interactionState, |
| onDragStopped = gestureEndAction, |
| startDragImmediately = position.holder.isRunning, |
| onDrag = { position.holder.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, |
| color, |
| maxPx, |
| interactionState, |
| modifier = press.plus(drag) |
| ) |
| } |
| } |
| |
| @Composable |
| private fun SliderImpl( |
| positionFraction: Float, |
| tickFractions: List<Float>, |
| color: Color, |
| width: Float, |
| interactionState: InteractionState, |
| modifier: Modifier |
| ) { |
| val widthDp = with(DensityAmbient.current) { |
| width.toDp() |
| } |
| Stack(modifier + DefaultSliderConstraints) { |
| val thumbSize = ThumbRadius * 2 |
| val offset = (widthDp - thumbSize) * positionFraction |
| val center = Modifier.gravity(Alignment.CenterStart) |
| |
| val trackStrokeWidth: Float |
| val thumbPx: Float |
| with(DensityAmbient.current) { |
| trackStrokeWidth = TrackHeight.toPx() |
| thumbPx = ThumbRadius.toPx() |
| } |
| Track( |
| center.fillMaxSize(), |
| color, |
| 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 = color, |
| elevation = elevation, |
| modifier = Modifier.indication( |
| interactionState = interactionState, |
| indication = RippleIndication( |
| radius = ThumbRippleRadius, |
| bounded = false |
| ) |
| ) |
| ) { |
| Spacer(Modifier.preferredSize(thumbSize, thumbSize)) |
| } |
| } |
| } |
| } |
| |
| @Composable |
| private fun Track( |
| modifier: Modifier, |
| color: Color, |
| positionFraction: Float, |
| tickFractions: List<Float>, |
| thumbPx: Float, |
| trackStrokeWidth: Float |
| ) { |
| val activeTickColor = MaterialTheme.colors.onPrimary.copy(alpha = TickColorAlpha) |
| val inactiveTickColor = color.copy(alpha = TickColorAlpha) |
| 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( |
| color.copy(alpha = InactiveTrackColorAlpha), |
| 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, |
| @IntRange(from = 0) steps: Int = 0 |
| ): Modifier { |
| val coerced = value.coerceIn(position.startValue, position.endValue) |
| val fraction = calcFraction(position.startValue, position.endValue, coerced) |
| // We only display 0% or 100% when it is exactly 0% or 100%. |
| val percent = when (fraction) { |
| 0f -> 0 |
| 1f -> 100 |
| else -> (fraction * 100).roundToInt().coerceIn(1, 99) |
| } |
| return semantics { |
| accessibilityValue = Strings.TemplatePercent.format(percent) |
| accessibilityValueRange = AccessibilityRangeInfo(coerced, valueRange) |
| setProgress(action = { setSliderProgress(it, coerced, position, onValueChange, steps) }) |
| |
| // TODO(b/157692376) Remove accessibility scroll actions in Slider when |
| // talkback is fixed |
| var increment = (position.endValue - position.startValue) / AccessibilityStepsCount |
| if (steps > 0) { |
| increment = (position.endValue - position.startValue) / (steps + 1) |
| } |
| if (coerced < position.endValue) { |
| @Suppress("DEPRECATION") |
| scrollForward(action = { |
| setSliderProgress(coerced + increment, coerced, position, onValueChange, steps) |
| }) |
| } |
| if (coerced > position.startValue) { |
| @Suppress("DEPRECATION") |
| scrollBackward(action = { |
| setSliderProgress(coerced - increment, coerced, position, onValueChange, steps) |
| }) |
| } |
| } |
| } |
| |
| private fun setSliderProgress( |
| targetValue: Float, |
| currentValue: Float, |
| position: SliderPosition, |
| onValueChange: (Float) -> Unit, |
| @IntRange(from = 0) steps: Int = 0 |
| ): Boolean { |
| var newValue = targetValue.coerceIn(position.startValue, position.endValue) |
| if (steps >= 0) { |
| val anchorsValue = position.tickFractions.map { |
| lerp(position.startValue, position.endValue, it) |
| } |
| val point = anchorsValue.minByOrNull { abs(it - newValue) } |
| newValue = point ?: newValue |
| } |
| // This is to keep it consistent with AbsSeekbar.java: return false if no |
| // change from current. |
| if (newValue == currentValue) { |
| return false |
| } |
| onValueChange(newValue) |
| return true |
| } |
| |
| // 20 is taken from AbsSeekbar.java. |
| private const val AccessibilityStepsCount = 20 |
| |
| /** |
| * 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 |
| */ |
| private class SliderPosition( |
| initial: Float = 0f, |
| val valueRange: ClosedFloatingPointRange<Float> = 0f..1f, |
| @IntRange(from = 0) steps: Int = 0, |
| animatedClock: AnimationClockObservable, |
| 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) { |
| holder.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.setBounds(min, max) |
| anchorsPx = tickFractions.map { |
| lerp(startPx, endPx, it) |
| } |
| holder.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 |
| |
| @Suppress("UnnecessaryLambdaCreation") |
| internal val holder = |
| CallbackBasedAnimatedFloat( |
| scale(startValue, endValue, initial, startPx, endPx), |
| animatedClock |
| ) { onValueChange(scale(startPx, endPx, it, startValue, endValue)) } |
| } |
| |
| private class CallbackBasedAnimatedFloat( |
| initial: Float, |
| clock: AnimationClockObservable, |
| var onValue: (Float) -> Unit |
| ) : AnimatedFloat(clock) { |
| |
| override var value = initial |
| set(value) { |
| onValue(value) |
| field = value |
| } |
| } |
| |
| // 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(minWidth = SliderMinWidth) |
| .preferredHeightIn(maxHeight = SliderHeight) |
| |
| // Internal to be referred to in tests |
| internal val InactiveTrackColorAlpha = 0.24f |
| private val TickColorAlpha = 0.54f |
| private val SliderToTickAnimation = TweenSpec<Float>(durationMillis = 100) |