| /* |
| * Copyright 2018 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.animation.AnimatedFloat |
| import androidx.animation.TweenBuilder |
| import androidx.compose.Composable |
| import androidx.ui.core.DensityAmbient |
| import androidx.ui.core.Modifier |
| import androidx.ui.foundation.Canvas |
| import androidx.ui.foundation.gestures.DragDirection |
| import androidx.ui.foundation.selection.Toggleable |
| import androidx.ui.geometry.Offset |
| import androidx.ui.graphics.Color |
| import androidx.ui.graphics.StrokeCap |
| import androidx.ui.graphics.painter.CanvasScope |
| import androidx.ui.graphics.painter.Stroke |
| import androidx.ui.layout.Stack |
| import androidx.ui.layout.padding |
| import androidx.ui.layout.preferredSize |
| import androidx.ui.material.internal.StateDraggable |
| import androidx.ui.material.ripple.ripple |
| import androidx.ui.semantics.Semantics |
| import androidx.ui.unit.dp |
| |
| /** |
| * A Switch is a two state toggleable component that provides on/off like options |
| * |
| * @sample androidx.ui.material.samples.SwitchSample |
| * |
| * @param checked whether or not this components is checked |
| * @param onCheckedChange callback to be invoked when Switch is being clicked, |
| * therefore the change of checked state is requested. |
| * @param enabled whether or not components is enabled and can be clicked to request state change |
| * @param color active color for Switch |
| */ |
| @Composable |
| fun Switch( |
| checked: Boolean, |
| onCheckedChange: (Boolean) -> Unit, |
| enabled: Boolean = true, |
| color: Color = MaterialTheme.colors.secondaryVariant |
| ) { |
| Semantics(container = true, mergeAllDescendants = true) { |
| Stack { |
| Toggleable( |
| value = checked, |
| onValueChange = onCheckedChange, |
| enabled = enabled, |
| modifier = Modifier.ripple(bounded = false, enabled = enabled) |
| ) { |
| SwitchImpl(checked, onCheckedChange, color, Modifier.padding(DefaultSwitchPadding)) |
| } |
| } |
| } |
| } |
| |
| @Composable |
| private fun SwitchImpl( |
| checked: Boolean, |
| onCheckedChange: ((Boolean) -> Unit)?, |
| color: Color, |
| modifier: Modifier |
| ) { |
| val minBound = 0f |
| val maxBound = with(DensityAmbient.current) { ThumbPathLength.toPx().value } |
| StateDraggable( |
| state = checked, |
| onStateChange = onCheckedChange ?: {}, |
| anchorsToState = listOf(minBound to false, maxBound to true), |
| animationBuilder = AnimationBuilder, |
| dragDirection = DragDirection.Horizontal, |
| minValue = minBound, |
| maxValue = maxBound |
| ) { model -> |
| DrawSwitch( |
| checked = checked, |
| checkedThumbColor = color, |
| thumbValue = model, |
| modifier = modifier |
| ) |
| } |
| } |
| |
| @Composable |
| private fun DrawSwitch( |
| checked: Boolean, |
| checkedThumbColor: Color, |
| thumbValue: AnimatedFloat, |
| modifier: Modifier |
| ) { |
| val thumbColor = if (checked) checkedThumbColor else MaterialTheme.colors.surface |
| val trackColor = if (checked) { |
| checkedThumbColor.copy(alpha = CheckedTrackOpacity) |
| } else { |
| MaterialTheme.colors.onSurface.copy(alpha = UncheckedTrackOpacity) |
| } |
| |
| val trackStroke: Stroke |
| val trackWidth: Float |
| val thumbDiameter: Float |
| with(DensityAmbient.current) { |
| trackStroke = Stroke(width = TrackStrokeWidth.toPx().value, cap = StrokeCap.round) |
| trackWidth = TrackWidth.toPx().value |
| thumbDiameter = ThumbDiameter.toPx().value |
| } |
| Canvas(modifier.preferredSize(SwitchWidth, SwitchHeight)) { |
| drawTrack(trackColor, trackWidth, trackStroke) |
| drawThumb(thumbValue.value, thumbDiameter, thumbColor) |
| } |
| } |
| |
| private fun CanvasScope.drawTrack(trackColor: Color, trackWidth: Float, stroke: Stroke) { |
| val strokeRadius = stroke.width / 2 |
| drawLine( |
| trackColor, |
| Offset(strokeRadius, center.dy), |
| Offset(trackWidth - strokeRadius, center.dy), |
| stroke |
| ) |
| } |
| |
| private fun CanvasScope.drawThumb(position: Float, thumbDiameter: Float, thumbColor: Color) { |
| val thumbRadius = thumbDiameter / 2 |
| val x = position + thumbRadius |
| drawCircle(thumbColor, thumbRadius, Offset(x, center.dy)) |
| } |
| |
| private const val CheckedTrackOpacity = 0.54f |
| private const val UncheckedTrackOpacity = 0.38f |
| |
| private val TrackWidth = 34.dp |
| private val TrackStrokeWidth = 14.dp |
| |
| private val ThumbDiameter = 20.dp |
| |
| // TODO(malkov): clarify this padding for Switch |
| private val DefaultSwitchPadding = 2.dp |
| private val SwitchWidth = TrackWidth |
| private val SwitchHeight = ThumbDiameter |
| private val ThumbPathLength = TrackWidth - ThumbDiameter |
| |
| private val AnimationBuilder = TweenBuilder<Float>().apply { duration = 100 } |