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January 25, 2023 13:17
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ModalBottomSheetLayout for Material 3 Jetpack Compose
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| package com.hse.parkingapp.ui.beta.screens.components.material3 | |
| /* | |
| * Copyright 2020 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. | |
| */ | |
| import androidx.compose.animation.core.AnimationSpec | |
| import androidx.compose.animation.core.TweenSpec | |
| import androidx.compose.animation.core.animateFloatAsState | |
| import androidx.compose.foundation.Canvas | |
| import androidx.compose.foundation.gestures.Orientation | |
| import androidx.compose.foundation.gestures.detectTapGestures | |
| import androidx.compose.foundation.layout.Box | |
| import androidx.compose.foundation.layout.BoxWithConstraints | |
| import androidx.compose.foundation.layout.Column | |
| import androidx.compose.foundation.layout.ColumnScope | |
| import androidx.compose.foundation.layout.fillMaxSize | |
| import androidx.compose.foundation.layout.fillMaxWidth | |
| import androidx.compose.foundation.layout.offset | |
| import androidx.compose.material3.ExperimentalMaterial3Api | |
| import androidx.compose.material3.MaterialTheme | |
| import androidx.compose.material3.Surface | |
| import androidx.compose.material3.contentColorFor | |
| import androidx.compose.runtime.Composable | |
| import androidx.compose.runtime.State | |
| import androidx.compose.runtime.getValue | |
| import androidx.compose.runtime.mutableStateOf | |
| import androidx.compose.runtime.remember | |
| import androidx.compose.runtime.rememberCoroutineScope | |
| import androidx.compose.runtime.saveable.Saver | |
| import androidx.compose.runtime.saveable.rememberSaveable | |
| import androidx.compose.ui.Modifier | |
| import androidx.compose.ui.graphics.Color | |
| import androidx.compose.ui.graphics.Shape | |
| import androidx.compose.ui.graphics.isSpecified | |
| import androidx.compose.ui.input.nestedscroll.nestedScroll | |
| import androidx.compose.ui.input.pointer.pointerInput | |
| import androidx.compose.ui.layout.onGloballyPositioned | |
| import androidx.compose.ui.semantics.collapse | |
| import androidx.compose.ui.semantics.contentDescription | |
| import androidx.compose.ui.semantics.dismiss | |
| import androidx.compose.ui.semantics.expand | |
| import androidx.compose.ui.semantics.onClick | |
| import androidx.compose.ui.semantics.semantics | |
| import androidx.compose.ui.unit.Dp | |
| import androidx.compose.ui.unit.IntOffset | |
| import androidx.compose.ui.unit.dp | |
| import kotlinx.coroutines.CancellationException | |
| import kotlinx.coroutines.launch | |
| import kotlin.math.max | |
| import kotlin.math.roundToInt | |
| /** | |
| * Possible values of [ModalBottomSheetState]. | |
| */ | |
| @ExperimentalMaterial3Api | |
| enum class ModalBottomSheetValue { | |
| /** | |
| * The bottom sheet is not visible. | |
| */ | |
| Hidden, | |
| /** | |
| * The bottom sheet is visible at full height. | |
| */ | |
| Expanded, | |
| /** | |
| * The bottom sheet is partially visible at 50% of the screen height. This state is only | |
| * enabled if the height of the bottom sheet is more than 50% of the screen height. | |
| */ | |
| HalfExpanded | |
| } | |
| /** | |
| * State of the [ModalBottomSheetLayout] composable. | |
| * | |
| * @param initialValue The initial value of the state. | |
| * @param animationSpec The default animation that will be used to animate to a new state. | |
| * @param confirmStateChange Optional callback invoked to confirm or veto a pending state change. | |
| */ | |
| @ExperimentalMaterial3Api | |
| class ModalBottomSheetState( | |
| initialValue: ModalBottomSheetValue, | |
| animationSpec: AnimationSpec<Float> = SwipeableDefaults.AnimationSpec, | |
| confirmStateChange: (ModalBottomSheetValue) -> Boolean = { true } | |
| ) : SwipeableState<ModalBottomSheetValue>( | |
| initialValue = initialValue, | |
| animationSpec = animationSpec, | |
| confirmStateChange = confirmStateChange | |
| ) { | |
| /** | |
| * Whether the bottom sheet is visible. | |
| */ | |
| val isVisible: Boolean | |
| get() = currentValue != ModalBottomSheetValue.Hidden | |
| internal val isHalfExpandedEnabled: Boolean | |
| get() = anchors.values.contains(ModalBottomSheetValue.HalfExpanded) | |
| /** | |
| * Show the bottom sheet with animation and suspend until it's shown. If half expand is | |
| * enabled, the bottom sheet will be half expanded. Otherwise it will be fully expanded. | |
| * | |
| * @throws [CancellationException] if the animation is interrupted | |
| */ | |
| suspend fun show() { | |
| val targetValue = | |
| if (isHalfExpandedEnabled) ModalBottomSheetValue.HalfExpanded | |
| else ModalBottomSheetValue.Expanded | |
| animateTo(targetValue = targetValue) | |
| } | |
| /** | |
| * Half expand the bottom sheet if half expand is enabled with animation and suspend until it | |
| * animation is complete or cancelled | |
| * | |
| * @throws [CancellationException] if the animation is interrupted | |
| */ | |
| internal suspend fun halfExpand() { | |
| if (!isHalfExpandedEnabled) { | |
| return | |
| } | |
| animateTo(ModalBottomSheetValue.HalfExpanded) | |
| } | |
| /** | |
| * Fully expand the bottom sheet with animation and suspend until it if fully expanded or | |
| * animation has been cancelled. | |
| * * | |
| * @throws [CancellationException] if the animation is interrupted | |
| */ | |
| internal suspend fun expand() = animateTo(ModalBottomSheetValue.Expanded) | |
| /** | |
| * Hide the bottom sheet with animation and suspend until it if fully hidden or animation has | |
| * been cancelled. | |
| * | |
| * @throws [CancellationException] if the animation is interrupted | |
| */ | |
| suspend fun hide() = animateTo(ModalBottomSheetValue.Hidden) | |
| internal val nestedScrollConnection = this.PreUpPostDownNestedScrollConnection | |
| companion object { | |
| /** | |
| * The default [Saver] implementation for [ModalBottomSheetState]. | |
| */ | |
| fun Saver( | |
| animationSpec: AnimationSpec<Float>, | |
| confirmStateChange: (ModalBottomSheetValue) -> Boolean | |
| ): Saver<ModalBottomSheetState, *> = Saver( | |
| save = { it.currentValue }, | |
| restore = { | |
| ModalBottomSheetState( | |
| initialValue = it, | |
| animationSpec = animationSpec, | |
| confirmStateChange = confirmStateChange | |
| ) | |
| } | |
| ) | |
| } | |
| } | |
| /** | |
| * Create a [ModalBottomSheetState] and [remember] it. | |
| * | |
| * @param initialValue The initial value of the state. | |
| * @param animationSpec The default animation that will be used to animate to a new state. | |
| * @param confirmStateChange Optional callback invoked to confirm or veto a pending state change. | |
| */ | |
| @Composable | |
| @ExperimentalMaterial3Api | |
| fun rememberModalBottomSheetState( | |
| initialValue: ModalBottomSheetValue, | |
| animationSpec: AnimationSpec<Float> = SwipeableDefaults.AnimationSpec, | |
| confirmStateChange: (ModalBottomSheetValue) -> Boolean = { true } | |
| ): ModalBottomSheetState { | |
| return rememberSaveable( | |
| saver = ModalBottomSheetState.Saver( | |
| animationSpec = animationSpec, | |
| confirmStateChange = confirmStateChange | |
| ) | |
| ) { | |
| ModalBottomSheetState( | |
| initialValue = initialValue, | |
| animationSpec = animationSpec, | |
| confirmStateChange = confirmStateChange | |
| ) | |
| } | |
| } | |
| /** | |
| * <a href="https://material.io/components/sheets-bottom#modal-bottom-sheet" class="external" target="_blank">Material Design modal bottom sheet</a>. | |
| * | |
| * Modal bottom sheets present a set of choices while blocking interaction with the rest of the | |
| * screen. They are an alternative to inline menus and simple dialogs, providing | |
| * additional room for content, iconography, and actions. | |
| * | |
| *  | |
| * | |
| * A simple example of a modal bottom sheet looks like this: | |
| * | |
| * @sample androidx.compose.material.samples.ModalBottomSheetSample | |
| * | |
| * @param sheetContent The content of the bottom sheet. | |
| * @param modifier Optional [Modifier] for the entire component. | |
| * @param sheetState The state of the bottom sheet. | |
| * @param sheetShape The shape of the bottom sheet. | |
| * @param sheetElevation The elevation of the bottom sheet. | |
| * @param sheetBackgroundColor The background color of the bottom sheet. | |
| * @param sheetContentColor The preferred content color provided by the bottom sheet to its | |
| * children. Defaults to the matching content color for [sheetBackgroundColor], or if that is not | |
| * a color from the theme, this will keep the same content color set above the bottom sheet. | |
| * @param scrimColor The color of the scrim that is applied to the rest of the screen when the | |
| * bottom sheet is visible. If the color passed is [Color.Unspecified], then a scrim will no | |
| * longer be applied and the bottom sheet will not block interaction with the rest of the screen | |
| * when visible. | |
| * @param content The content of rest of the screen. | |
| */ | |
| @Composable | |
| @ExperimentalMaterial3Api | |
| fun ModalBottomSheetLayout( | |
| sheetContent: @Composable ColumnScope.() -> Unit, | |
| modifier: Modifier = Modifier, | |
| sheetState: ModalBottomSheetState = | |
| rememberModalBottomSheetState(ModalBottomSheetValue.Hidden), | |
| sheetShape: Shape = MaterialTheme.shapes.large, | |
| sheetElevation: Dp = ModalBottomSheetDefaults.Elevation, | |
| sheetBackgroundColor: Color = MaterialTheme.colorScheme.surface, | |
| sheetContentColor: Color = contentColorFor(sheetBackgroundColor), | |
| scrimColor: Color = ModalBottomSheetDefaults.scrimColor, | |
| content: @Composable () -> Unit | |
| ) { | |
| val scope = rememberCoroutineScope() | |
| BoxWithConstraints(modifier) { | |
| val fullHeight = constraints.maxHeight.toFloat() | |
| val sheetHeightState = remember { mutableStateOf<Float?>(null) } | |
| Box(Modifier.fillMaxSize()) { | |
| content() | |
| Scrim( | |
| color = scrimColor, | |
| onDismiss = { | |
| if (sheetState.confirmStateChange(ModalBottomSheetValue.Hidden)) { | |
| scope.launch { sheetState.hide() } | |
| } | |
| }, | |
| visible = sheetState.targetValue != ModalBottomSheetValue.Hidden | |
| ) | |
| } | |
| Surface( | |
| modifier = Modifier | |
| .fillMaxWidth() | |
| .nestedScroll(sheetState.nestedScrollConnection) | |
| .offset { | |
| val y = if (sheetState.anchors.isEmpty()) { | |
| // if we don't know our anchors yet, render the sheet as hidden | |
| fullHeight.roundToInt() | |
| } else { | |
| // if we do know our anchors, respect them | |
| sheetState.offset.value.roundToInt() | |
| } | |
| IntOffset(0, y) | |
| } | |
| .bottomSheetSwipeable(sheetState, fullHeight, sheetHeightState) | |
| .onGloballyPositioned { | |
| sheetHeightState.value = it.size.height.toFloat() | |
| } | |
| .semantics { | |
| if (sheetState.isVisible) { | |
| dismiss { | |
| if (sheetState.confirmStateChange(ModalBottomSheetValue.Hidden)) { | |
| scope.launch { sheetState.hide() } | |
| } | |
| true | |
| } | |
| if (sheetState.currentValue == ModalBottomSheetValue.HalfExpanded) { | |
| expand { | |
| if (sheetState.confirmStateChange(ModalBottomSheetValue.Expanded)) { | |
| scope.launch { sheetState.expand() } | |
| } | |
| true | |
| } | |
| } else if (sheetState.isHalfExpandedEnabled) { | |
| collapse { | |
| if (sheetState.confirmStateChange(ModalBottomSheetValue.HalfExpanded)) { | |
| scope.launch { sheetState.halfExpand() } | |
| } | |
| true | |
| } | |
| } | |
| } | |
| }, | |
| shape = sheetShape, | |
| tonalElevation = sheetElevation, | |
| color = sheetBackgroundColor, | |
| contentColor = sheetContentColor | |
| ) { | |
| Column(content = sheetContent) | |
| } | |
| } | |
| } | |
| @Suppress("ModifierInspectorInfo") | |
| @OptIn(ExperimentalMaterial3Api::class) | |
| private fun Modifier.bottomSheetSwipeable( | |
| sheetState: ModalBottomSheetState, | |
| fullHeight: Float, | |
| sheetHeightState: State<Float?> | |
| ): Modifier { | |
| val sheetHeight = sheetHeightState.value | |
| val modifier = if (sheetHeight != null) { | |
| val anchors = if (sheetHeight < fullHeight / 2) { | |
| mapOf( | |
| fullHeight to ModalBottomSheetValue.Hidden, | |
| fullHeight - sheetHeight to ModalBottomSheetValue.Expanded | |
| ) | |
| } else { | |
| mapOf( | |
| fullHeight to ModalBottomSheetValue.Hidden, | |
| fullHeight / 2 to ModalBottomSheetValue.HalfExpanded, | |
| max(0f, fullHeight - sheetHeight) to ModalBottomSheetValue.Expanded | |
| ) | |
| } | |
| Modifier.swipeable( | |
| state = sheetState, | |
| anchors = anchors, | |
| orientation = Orientation.Vertical, | |
| enabled = sheetState.currentValue != ModalBottomSheetValue.Hidden, | |
| resistance = null | |
| ) | |
| } else { | |
| Modifier | |
| } | |
| return this.then(modifier) | |
| } | |
| @Composable | |
| private fun Scrim( | |
| color: Color, | |
| onDismiss: () -> Unit, | |
| visible: Boolean | |
| ) { | |
| if (color.isSpecified) { | |
| val alpha by animateFloatAsState( | |
| targetValue = if (visible) 1f else 0f, | |
| animationSpec = TweenSpec() | |
| ) | |
| val closeSheet = getString(Strings.CloseSheet) | |
| val dismissModifier = if (visible) { | |
| Modifier | |
| .pointerInput(onDismiss) { detectTapGestures { onDismiss() } } | |
| .semantics(mergeDescendants = true) { | |
| contentDescription = closeSheet | |
| onClick { onDismiss(); true } | |
| } | |
| } else { | |
| Modifier | |
| } | |
| Canvas( | |
| Modifier | |
| .fillMaxSize() | |
| .then(dismissModifier) | |
| ) { | |
| drawRect(color = color, alpha = alpha) | |
| } | |
| } | |
| } | |
| /** | |
| * Contains useful Defaults for [ModalBottomSheetLayout]. | |
| */ | |
| object ModalBottomSheetDefaults { | |
| /** | |
| * The default elevation used by [ModalBottomSheetLayout]. | |
| */ | |
| val Elevation = 16.dp | |
| /** | |
| * The default scrim color used by [ModalBottomSheetLayout]. | |
| */ | |
| val scrimColor: Color | |
| @Composable | |
| get() = MaterialTheme.colorScheme.onSecondary.copy(alpha = 0.7f) | |
| } |
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| package com.hse.parkingapp.ui.beta.screens.components.material3 | |
| /* | |
| * Copyright 2021 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. | |
| */ | |
| import androidx.compose.runtime.Composable | |
| import androidx.compose.ui.R | |
| import androidx.compose.ui.platform.LocalConfiguration | |
| import androidx.compose.ui.platform.LocalContext | |
| import androidx.compose.runtime.Immutable | |
| @Immutable | |
| @kotlin.jvm.JvmInline | |
| value class Strings private constructor(@Suppress("unused") private val value: Int) { | |
| companion object { | |
| val NavigationMenu = Strings(0) | |
| val CloseDrawer = Strings(1) | |
| val CloseSheet = Strings(2) | |
| val DefaultErrorMessage = Strings(3) | |
| val ExposedDropdownMenu = Strings(4) | |
| val SliderRangeStart = Strings(5) | |
| val SliderRangeEnd = Strings(6) | |
| } | |
| } | |
| @Composable | |
| fun getString(string: Strings): String { | |
| LocalConfiguration.current | |
| val resources = LocalContext.current.resources | |
| return when (string) { | |
| Strings.NavigationMenu -> resources.getString(R.string.navigation_menu) | |
| Strings.CloseDrawer -> resources.getString(R.string.close_drawer) | |
| Strings.CloseSheet -> resources.getString(R.string.close_sheet) | |
| Strings.DefaultErrorMessage -> resources.getString(R.string.default_error_message) | |
| Strings.ExposedDropdownMenu -> resources.getString(R.string.dropdown_menu) | |
| Strings.SliderRangeStart -> resources.getString(R.string.range_start) | |
| Strings.SliderRangeEnd -> resources.getString(R.string.range_end) | |
| else -> "" | |
| } | |
| } |
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| package com.hse.parkingapp.ui.beta.screens.components.material3 | |
| /* | |
| * Copyright 2020 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. | |
| */ | |
| import androidx.compose.animation.core.Animatable | |
| import androidx.compose.animation.core.AnimationSpec | |
| import androidx.compose.animation.core.SpringSpec | |
| import androidx.compose.foundation.gestures.DraggableState | |
| import androidx.compose.foundation.gestures.Orientation | |
| import androidx.compose.foundation.gestures.draggable | |
| import androidx.compose.foundation.interaction.MutableInteractionSource | |
| import androidx.compose.material3.ExperimentalMaterial3Api | |
| import androidx.compose.runtime.Composable | |
| import androidx.compose.runtime.DisposableEffect | |
| import androidx.compose.runtime.Immutable | |
| import androidx.compose.runtime.LaunchedEffect | |
| import androidx.compose.runtime.Stable | |
| import androidx.compose.runtime.State | |
| import androidx.compose.runtime.getValue | |
| import androidx.compose.runtime.mutableStateOf | |
| import androidx.compose.runtime.remember | |
| import androidx.compose.runtime.saveable.Saver | |
| import androidx.compose.runtime.saveable.rememberSaveable | |
| import androidx.compose.runtime.setValue | |
| import androidx.compose.runtime.snapshotFlow | |
| import androidx.compose.ui.Modifier | |
| import androidx.compose.ui.composed | |
| import androidx.compose.ui.geometry.Offset | |
| import androidx.compose.ui.input.nestedscroll.NestedScrollConnection | |
| import androidx.compose.ui.input.nestedscroll.NestedScrollSource | |
| import androidx.compose.ui.platform.LocalDensity | |
| import androidx.compose.ui.platform.debugInspectorInfo | |
| import androidx.compose.ui.unit.Density | |
| import androidx.compose.ui.unit.Dp | |
| import androidx.compose.ui.unit.Velocity | |
| import androidx.compose.ui.unit.dp | |
| import androidx.compose.ui.util.lerp | |
| import com.hse.parkingapp.ui.beta.screens.components.material3.SwipeableDefaults.StandardResistanceFactor | |
| import com.hse.parkingapp.ui.beta.screens.components.material3.SwipeableDefaults.VelocityThreshold | |
| import com.hse.parkingapp.ui.beta.screens.components.material3.SwipeableDefaults.resistanceConfig | |
| import kotlinx.coroutines.CancellationException | |
| import kotlinx.coroutines.flow.Flow | |
| import kotlinx.coroutines.flow.filter | |
| import kotlinx.coroutines.flow.take | |
| import kotlinx.coroutines.launch | |
| import kotlin.math.PI | |
| import kotlin.math.abs | |
| import kotlin.math.sign | |
| import kotlin.math.sin | |
| /** | |
| * State of the [swipeable] modifier. | |
| * | |
| * This contains necessary information about any ongoing swipe or animation and provides methods | |
| * to change the state either immediately or by starting an animation. To create and remember a | |
| * [SwipeableState] with the default animation clock, use [rememberSwipeableState]. | |
| * | |
| * @param initialValue The initial value of the state. | |
| * @param animationSpec The default animation that will be used to animate to a new state. | |
| * @param confirmStateChange Optional callback invoked to confirm or veto a pending state change. | |
| */ | |
| @Stable | |
| @ExperimentalMaterial3Api | |
| open class SwipeableState<T>( | |
| initialValue: T, | |
| internal val animationSpec: AnimationSpec<Float> = SwipeableDefaults.AnimationSpec, | |
| internal val confirmStateChange: (newValue: T) -> Boolean = { true } | |
| ) { | |
| /** | |
| * The current value of the state. | |
| * | |
| * If no swipe or animation is in progress, this corresponds to the anchor at which the | |
| * [swipeable] is currently settled. If a swipe or animation is in progress, this corresponds | |
| * the last anchor at which the [swipeable] was settled before the swipe or animation started. | |
| */ | |
| var currentValue: T by mutableStateOf(initialValue) | |
| private set | |
| /** | |
| * Whether the state is currently animating. | |
| */ | |
| var isAnimationRunning: Boolean by mutableStateOf(false) | |
| private set | |
| /** | |
| * The current position (in pixels) of the [swipeable]. | |
| * | |
| * You should use this state to offset your content accordingly. The recommended way is to | |
| * use `Modifier.offsetPx`. This includes the resistance by default, if resistance is enabled. | |
| */ | |
| val offset: State<Float> get() = offsetState | |
| /** | |
| * The amount by which the [swipeable] has been swiped past its bounds. | |
| */ | |
| val overflow: State<Float> get() = overflowState | |
| // Use `Float.NaN` as a placeholder while the state is uninitialised. | |
| private val offsetState = mutableStateOf(0f) | |
| private val overflowState = mutableStateOf(0f) | |
| // the source of truth for the "real"(non ui) position | |
| // basically position in bounds + overflow | |
| private val absoluteOffset = mutableStateOf(0f) | |
| // current animation target, if animating, otherwise null | |
| private val animationTarget = mutableStateOf<Float?>(null) | |
| internal var anchors by mutableStateOf(emptyMap<Float, T>()) | |
| private val latestNonEmptyAnchorsFlow: Flow<Map<Float, T>> = | |
| snapshotFlow { anchors } | |
| .filter { it.isNotEmpty() } | |
| .take(1) | |
| internal var minBound = Float.NEGATIVE_INFINITY | |
| internal var maxBound = Float.POSITIVE_INFINITY | |
| internal fun ensureInit(newAnchors: Map<Float, T>) { | |
| if (anchors.isEmpty()) { | |
| // need to do initial synchronization synchronously :( | |
| val initialOffset = newAnchors.getOffset(currentValue) | |
| requireNotNull(initialOffset) { | |
| "The initial value must have an associated anchor." | |
| } | |
| offsetState.value = initialOffset | |
| absoluteOffset.value = initialOffset | |
| } | |
| } | |
| internal suspend fun processNewAnchors( | |
| oldAnchors: Map<Float, T>, | |
| newAnchors: Map<Float, T> | |
| ) { | |
| if (oldAnchors.isEmpty()) { | |
| // If this is the first time that we receive anchors, then we need to initialise | |
| // the state so we snap to the offset associated to the initial value. | |
| minBound = newAnchors.keys.minOrNull()!! | |
| maxBound = newAnchors.keys.maxOrNull()!! | |
| val initialOffset = newAnchors.getOffset(currentValue) | |
| requireNotNull(initialOffset) { | |
| "The initial value must have an associated anchor." | |
| } | |
| snapInternalToOffset(initialOffset) | |
| } else if (newAnchors != oldAnchors) { | |
| // If we have received new anchors, then the offset of the current value might | |
| // have changed, so we need to animate to the new offset. If the current value | |
| // has been removed from the anchors then we animate to the closest anchor | |
| // instead. Note that this stops any ongoing animation. | |
| minBound = Float.NEGATIVE_INFINITY | |
| maxBound = Float.POSITIVE_INFINITY | |
| val animationTargetValue = animationTarget.value | |
| // if we're in the animation already, let's find it a new home | |
| val targetOffset = if (animationTargetValue != null) { | |
| // first, try to map old state to the new state | |
| val oldState = oldAnchors[animationTargetValue] | |
| val newState = newAnchors.getOffset(oldState) | |
| // return new state if exists, or find the closes one among new anchors | |
| newState ?: newAnchors.keys.minByOrNull { abs(it - animationTargetValue) }!! | |
| } else { | |
| // we're not animating, proceed by finding the new anchors for an old value | |
| val actualOldValue = oldAnchors[offset.value] | |
| val value = if (actualOldValue == currentValue) currentValue else actualOldValue | |
| newAnchors.getOffset(value) ?: newAnchors | |
| .keys.minByOrNull { abs(it - offset.value) }!! | |
| } | |
| try { | |
| animateInternalToOffset(targetOffset, animationSpec) | |
| } catch (c: CancellationException) { | |
| // If the animation was interrupted for any reason, snap as a last resort. | |
| snapInternalToOffset(targetOffset) | |
| } finally { | |
| currentValue = newAnchors.getValue(targetOffset) | |
| minBound = newAnchors.keys.minOrNull()!! | |
| maxBound = newAnchors.keys.maxOrNull()!! | |
| } | |
| } | |
| } | |
| internal var thresholds: (Float, Float) -> Float by mutableStateOf({ _, _ -> 0f }) | |
| internal var velocityThreshold by mutableStateOf(0f) | |
| internal var resistance: ResistanceConfig? by mutableStateOf(null) | |
| internal val draggableState = DraggableState { | |
| val newAbsolute = absoluteOffset.value + it | |
| val clamped = newAbsolute.coerceIn(minBound, maxBound) | |
| val overflow = newAbsolute - clamped | |
| val resistanceDelta = resistance?.computeResistance(overflow) ?: 0f | |
| offsetState.value = clamped + resistanceDelta | |
| overflowState.value = overflow | |
| absoluteOffset.value = newAbsolute | |
| } | |
| private suspend fun snapInternalToOffset(target: Float) { | |
| draggableState.drag { | |
| dragBy(target - absoluteOffset.value) | |
| } | |
| } | |
| private suspend fun animateInternalToOffset(target: Float, spec: AnimationSpec<Float>) { | |
| draggableState.drag { | |
| var prevValue = absoluteOffset.value | |
| animationTarget.value = target | |
| isAnimationRunning = true | |
| try { | |
| Animatable(prevValue).animateTo(target, spec) { | |
| dragBy(this.value - prevValue) | |
| prevValue = this.value | |
| } | |
| } finally { | |
| animationTarget.value = null | |
| isAnimationRunning = false | |
| } | |
| } | |
| } | |
| /** | |
| * The target value of the state. | |
| * | |
| * If a swipe is in progress, this is the value that the [swipeable] would animate to if the | |
| * swipe finished. If an animation is running, this is the target value of that animation. | |
| * Finally, if no swipe or animation is in progress, this is the same as the [currentValue]. | |
| */ | |
| @ExperimentalMaterial3Api | |
| val targetValue: T | |
| get() { | |
| // TODO(calintat): Track current velocity (b/149549482) and use that here. | |
| val target = animationTarget.value ?: computeTarget( | |
| offset = offset.value, | |
| lastValue = anchors.getOffset(currentValue) ?: offset.value, | |
| anchors = anchors.keys, | |
| thresholds = thresholds, | |
| velocity = 0f, | |
| velocityThreshold = Float.POSITIVE_INFINITY | |
| ) | |
| return anchors[target] ?: currentValue | |
| } | |
| /** | |
| * Information about the ongoing swipe or animation, if any. See [SwipeProgress] for details. | |
| * | |
| * If no swipe or animation is in progress, this returns `SwipeProgress(value, value, 1f)`. | |
| */ | |
| @ExperimentalMaterial3Api | |
| val progress: SwipeProgress<T> | |
| get() { | |
| val bounds = findBounds(offset.value, anchors.keys) | |
| val from: T | |
| val to: T | |
| val fraction: Float | |
| when (bounds.size) { | |
| 0 -> { | |
| from = currentValue | |
| to = currentValue | |
| fraction = 1f | |
| } | |
| 1 -> { | |
| from = anchors.getValue(bounds[0]) | |
| to = anchors.getValue(bounds[0]) | |
| fraction = 1f | |
| } | |
| else -> { | |
| val (a, b) = | |
| if (direction > 0f) { | |
| bounds[0] to bounds[1] | |
| } else { | |
| bounds[1] to bounds[0] | |
| } | |
| from = anchors.getValue(a) | |
| to = anchors.getValue(b) | |
| fraction = (offset.value - a) / (b - a) | |
| } | |
| } | |
| return SwipeProgress(from, to, fraction) | |
| } | |
| /** | |
| * The direction in which the [swipeable] is moving, relative to the current [currentValue]. | |
| * | |
| * This will be either 1f if it is is moving from left to right or top to bottom, -1f if it is | |
| * moving from right to left or bottom to top, or 0f if no swipe or animation is in progress. | |
| */ | |
| @ExperimentalMaterial3Api | |
| val direction: Float | |
| get() = anchors.getOffset(currentValue)?.let { sign(offset.value - it) } ?: 0f | |
| /** | |
| * Set the state without any animation and suspend until it's set | |
| * | |
| * @param targetValue The new target value to set [currentValue] to. | |
| */ | |
| @ExperimentalMaterial3Api | |
| suspend fun snapTo(targetValue: T) { | |
| latestNonEmptyAnchorsFlow.collect { anchors -> | |
| val targetOffset = anchors.getOffset(targetValue) | |
| requireNotNull(targetOffset) { | |
| "The target value must have an associated anchor." | |
| } | |
| snapInternalToOffset(targetOffset) | |
| currentValue = targetValue | |
| } | |
| } | |
| /** | |
| * Set the state to the target value by starting an animation. | |
| * | |
| * @param targetValue The new value to animate to. | |
| * @param anim The animation that will be used to animate to the new value. | |
| */ | |
| @ExperimentalMaterial3Api | |
| suspend fun animateTo(targetValue: T, anim: AnimationSpec<Float> = animationSpec) { | |
| latestNonEmptyAnchorsFlow.collect { anchors -> | |
| try { | |
| val targetOffset = anchors.getOffset(targetValue) | |
| requireNotNull(targetOffset) { | |
| "The target value must have an associated anchor." | |
| } | |
| animateInternalToOffset(targetOffset, anim) | |
| } finally { | |
| val endOffset = absoluteOffset.value | |
| val endValue = anchors | |
| // fighting rounding error once again, anchor should be as close as 0.5 pixels | |
| .filterKeys { anchorOffset -> abs(anchorOffset - endOffset) < 0.5f } | |
| .values.firstOrNull() ?: currentValue | |
| currentValue = endValue | |
| } | |
| } | |
| } | |
| /** | |
| * Perform fling with settling to one of the anchors which is determined by the given | |
| * [velocity]. Fling with settling [swipeable] will always consume all the velocity provided | |
| * since it will settle at the anchor. | |
| * | |
| * In general cases, [swipeable] flings by itself when being swiped. This method is to be | |
| * used for nested scroll logic that wraps the [swipeable]. In nested scroll developer may | |
| * want to trigger settling fling when the child scroll container reaches the bound. | |
| * | |
| * @param velocity velocity to fling and settle with | |
| * | |
| * @return the reason fling ended | |
| */ | |
| suspend fun performFling(velocity: Float) { | |
| latestNonEmptyAnchorsFlow.collect { anchors -> | |
| val lastAnchor = anchors.getOffset(currentValue)!! | |
| val targetValue = computeTarget( | |
| offset = offset.value, | |
| lastValue = lastAnchor, | |
| anchors = anchors.keys, | |
| thresholds = thresholds, | |
| velocity = velocity, | |
| velocityThreshold = velocityThreshold | |
| ) | |
| val targetState = anchors[targetValue] | |
| if (targetState != null && confirmStateChange(targetState)) animateTo(targetState) | |
| // If the user vetoed the state change, rollback to the previous state. | |
| else animateInternalToOffset(lastAnchor, animationSpec) | |
| } | |
| } | |
| /** | |
| * Force [swipeable] to consume drag delta provided from outside of the regular [swipeable] | |
| * gesture flow. | |
| * | |
| * Note: This method performs generic drag and it won't settle to any particular anchor, * | |
| * leaving swipeable in between anchors. When done dragging, [performFling] must be | |
| * called as well to ensure swipeable will settle at the anchor. | |
| * | |
| * In general cases, [swipeable] drags by itself when being swiped. This method is to be | |
| * used for nested scroll logic that wraps the [swipeable]. In nested scroll developer may | |
| * want to force drag when the child scroll container reaches the bound. | |
| * | |
| * @param delta delta in pixels to drag by | |
| * | |
| * @return the amount of [delta] consumed | |
| */ | |
| fun performDrag(delta: Float): Float { | |
| val potentiallyConsumed = absoluteOffset.value + delta | |
| val clamped = potentiallyConsumed.coerceIn(minBound, maxBound) | |
| val deltaToConsume = clamped - absoluteOffset.value | |
| if (abs(deltaToConsume) > 0) { | |
| draggableState.dispatchRawDelta(deltaToConsume) | |
| } | |
| return deltaToConsume | |
| } | |
| companion object { | |
| /** | |
| * The default [Saver] implementation for [SwipeableState]. | |
| */ | |
| fun <T : Any> Saver( | |
| animationSpec: AnimationSpec<Float>, | |
| confirmStateChange: (T) -> Boolean | |
| ) = Saver<SwipeableState<T>, T>( | |
| save = { it.currentValue }, | |
| restore = { SwipeableState(it, animationSpec, confirmStateChange) } | |
| ) | |
| } | |
| } | |
| /** | |
| * Collects information about the ongoing swipe or animation in [swipeable]. | |
| * | |
| * To access this information, use [SwipeableState.progress]. | |
| * | |
| * @param from The state corresponding to the anchor we are moving away from. | |
| * @param to The state corresponding to the anchor we are moving towards. | |
| * @param fraction The fraction that the current position represents between [from] and [to]. | |
| * Must be between `0` and `1`. | |
| */ | |
| @Immutable | |
| @ExperimentalMaterial3Api | |
| class SwipeProgress<T>( | |
| val from: T, | |
| val to: T, | |
| /*@FloatRange(from = 0.0, to = 1.0)*/ | |
| val fraction: Float | |
| ) { | |
| override fun equals(other: Any?): Boolean { | |
| if (this === other) return true | |
| if (other !is SwipeProgress<*>) return false | |
| if (from != other.from) return false | |
| if (to != other.to) return false | |
| if (fraction != other.fraction) return false | |
| return true | |
| } | |
| override fun hashCode(): Int { | |
| var result = from?.hashCode() ?: 0 | |
| result = 31 * result + (to?.hashCode() ?: 0) | |
| result = 31 * result + fraction.hashCode() | |
| return result | |
| } | |
| override fun toString(): String { | |
| return "SwipeProgress(from=$from, to=$to, fraction=$fraction)" | |
| } | |
| } | |
| /** | |
| * Create and [remember] a [SwipeableState] with the default animation clock. | |
| * | |
| * @param initialValue The initial value of the state. | |
| * @param animationSpec The default animation that will be used to animate to a new state. | |
| * @param confirmStateChange Optional callback invoked to confirm or veto a pending state change. | |
| */ | |
| @Composable | |
| @ExperimentalMaterial3Api | |
| fun <T : Any> rememberSwipeableState( | |
| initialValue: T, | |
| animationSpec: AnimationSpec<Float> = SwipeableDefaults.AnimationSpec, | |
| confirmStateChange: (newValue: T) -> Boolean = { true } | |
| ): SwipeableState<T> { | |
| return rememberSaveable( | |
| saver = SwipeableState.Saver( | |
| animationSpec = animationSpec, | |
| confirmStateChange = confirmStateChange | |
| ) | |
| ) { | |
| SwipeableState( | |
| initialValue = initialValue, | |
| animationSpec = animationSpec, | |
| confirmStateChange = confirmStateChange | |
| ) | |
| } | |
| } | |
| /** | |
| * Create and [remember] a [SwipeableState] which is kept in sync with another state, i.e.: | |
| * 1. Whenever the [value] changes, the [SwipeableState] will be animated to that new value. | |
| * 2. Whenever the value of the [SwipeableState] changes (e.g. after a swipe), the owner of the | |
| * [value] will be notified to update their state to the new value of the [SwipeableState] by | |
| * invoking [onValueChange]. If the owner does not update their state to the provided value for | |
| * some reason, then the [SwipeableState] will perform a rollback to the previous, correct value. | |
| */ | |
| @Composable | |
| @ExperimentalMaterial3Api | |
| internal fun <T : Any> rememberSwipeableStateFor( | |
| value: T, | |
| onValueChange: (T) -> Unit, | |
| animationSpec: AnimationSpec<Float> = SwipeableDefaults.AnimationSpec | |
| ): SwipeableState<T> { | |
| val swipeableState = remember { | |
| SwipeableState( | |
| initialValue = value, | |
| animationSpec = animationSpec, | |
| confirmStateChange = { true } | |
| ) | |
| } | |
| val forceAnimationCheck = remember { mutableStateOf(false) } | |
| LaunchedEffect(value, forceAnimationCheck.value) { | |
| if (value != swipeableState.currentValue) { | |
| swipeableState.animateTo(value) | |
| } | |
| } | |
| DisposableEffect(swipeableState.currentValue) { | |
| if (value != swipeableState.currentValue) { | |
| onValueChange(swipeableState.currentValue) | |
| forceAnimationCheck.value = !forceAnimationCheck.value | |
| } | |
| onDispose { } | |
| } | |
| return swipeableState | |
| } | |
| /** | |
| * Enable swipe gestures between a set of predefined states. | |
| * | |
| * To use this, you must provide a map of anchors (in pixels) to states (of type [T]). | |
| * Note that this map cannot be empty and cannot have two anchors mapped to the same state. | |
| * | |
| * When a swipe is detected, the offset of the [SwipeableState] will be updated with the swipe | |
| * delta. You should use this offset to move your content accordingly (see `Modifier.offsetPx`). | |
| * When the swipe ends, the offset will be animated to one of the anchors and when that anchor is | |
| * reached, the value of the [SwipeableState] will also be updated to the state corresponding to | |
| * the new anchor. The target anchor is calculated based on the provided positional [thresholds]. | |
| * | |
| * Swiping is constrained between the minimum and maximum anchors. If the user attempts to swipe | |
| * past these bounds, a resistance effect will be applied by default. The amount of resistance at | |
| * each edge is specified by the [resistance] config. To disable all resistance, set it to `null`. | |
| * | |
| * For an example of a [swipeable] with three states, see: | |
| * | |
| * @sample androidx.compose.material.samples.SwipeableSample | |
| * | |
| * @param T The type of the state. | |
| * @param state The state of the [swipeable]. | |
| * @param anchors Pairs of anchors and states, used to map anchors to states and vice versa. | |
| * @param thresholds Specifies where the thresholds between the states are. The thresholds will be | |
| * used to determine which state to animate to when swiping stops. This is represented as a lambda | |
| * that takes two states and returns the threshold between them in the form of a [ThresholdConfig]. | |
| * Note that the order of the states corresponds to the swipe direction. | |
| * @param orientation The orientation in which the [swipeable] can be swiped. | |
| * @param enabled Whether this [swipeable] is enabled and should react to the user's input. | |
| * @param reverseDirection Whether to reverse the direction of the swipe, so a top to bottom | |
| * swipe will behave like bottom to top, and a left to right swipe will behave like right to left. | |
| * @param interactionSource Optional [MutableInteractionSource] that will passed on to | |
| * the internal [Modifier.draggable]. | |
| * @param resistance Controls how much resistance will be applied when swiping past the bounds. | |
| * @param velocityThreshold The threshold (in dp per second) that the end velocity has to exceed | |
| * in order to animate to the next state, even if the positional [thresholds] have not been reached. | |
| */ | |
| @ExperimentalMaterial3Api | |
| fun <T> Modifier.swipeable( | |
| state: SwipeableState<T>, | |
| anchors: Map<Float, T>, | |
| orientation: Orientation, | |
| enabled: Boolean = true, | |
| reverseDirection: Boolean = false, | |
| interactionSource: MutableInteractionSource? = null, | |
| thresholds: (from: T, to: T) -> ThresholdConfig = { _, _ -> FixedThreshold(56.dp) }, | |
| resistance: ResistanceConfig? = resistanceConfig(anchors.keys), | |
| velocityThreshold: Dp = VelocityThreshold | |
| ) = composed( | |
| inspectorInfo = debugInspectorInfo { | |
| name = "swipeable" | |
| properties["state"] = state | |
| properties["anchors"] = anchors | |
| properties["orientation"] = orientation | |
| properties["enabled"] = enabled | |
| properties["reverseDirection"] = reverseDirection | |
| properties["interactionSource"] = interactionSource | |
| properties["thresholds"] = thresholds | |
| properties["resistance"] = resistance | |
| properties["velocityThreshold"] = velocityThreshold | |
| } | |
| ) { | |
| require(anchors.isNotEmpty()) { | |
| "You must have at least one anchor." | |
| } | |
| require(anchors.values.distinct().count() == anchors.size) { | |
| "You cannot have two anchors mapped to the same state." | |
| } | |
| val density = LocalDensity.current | |
| state.ensureInit(anchors) | |
| LaunchedEffect(anchors, state) { | |
| val oldAnchors = state.anchors | |
| state.anchors = anchors | |
| state.resistance = resistance | |
| state.thresholds = { a, b -> | |
| val from = anchors.getValue(a) | |
| val to = anchors.getValue(b) | |
| with(thresholds(from, to)) { density.computeThreshold(a, b) } | |
| } | |
| with(density) { | |
| state.velocityThreshold = velocityThreshold.toPx() | |
| } | |
| state.processNewAnchors(oldAnchors, anchors) | |
| } | |
| Modifier.draggable( | |
| orientation = orientation, | |
| enabled = enabled, | |
| reverseDirection = reverseDirection, | |
| interactionSource = interactionSource, | |
| startDragImmediately = state.isAnimationRunning, | |
| onDragStopped = { velocity -> launch { state.performFling(velocity) } }, | |
| state = state.draggableState | |
| ) | |
| } | |
| /** | |
| * Interface to compute a threshold between two anchors/states in a [swipeable]. | |
| * | |
| * To define a [ThresholdConfig], consider using [FixedThreshold] and [FractionalThreshold]. | |
| */ | |
| @Stable | |
| @ExperimentalMaterial3Api | |
| interface ThresholdConfig { | |
| /** | |
| * Compute the value of the threshold (in pixels), once the values of the anchors are known. | |
| */ | |
| fun Density.computeThreshold(fromValue: Float, toValue: Float): Float | |
| } | |
| /** | |
| * A fixed threshold will be at an [offset] away from the first anchor. | |
| * | |
| * @param offset The offset (in dp) that the threshold will be at. | |
| */ | |
| @Immutable | |
| @ExperimentalMaterial3Api | |
| data class FixedThreshold(private val offset: Dp) : ThresholdConfig { | |
| override fun Density.computeThreshold(fromValue: Float, toValue: Float): Float { | |
| return fromValue + offset.toPx() * sign(toValue - fromValue) | |
| } | |
| } | |
| /** | |
| * A fractional threshold will be at a [fraction] of the way between the two anchors. | |
| * | |
| * @param fraction The fraction (between 0 and 1) that the threshold will be at. | |
| */ | |
| @Immutable | |
| @ExperimentalMaterial3Api | |
| data class FractionalThreshold( | |
| /*@FloatRange(from = 0.0, to = 1.0)*/ | |
| private val fraction: Float | |
| ) : ThresholdConfig { | |
| override fun Density.computeThreshold(fromValue: Float, toValue: Float): Float { | |
| return lerp(fromValue, toValue, fraction) | |
| } | |
| } | |
| /** | |
| * Specifies how resistance is calculated in [swipeable]. | |
| * | |
| * There are two things needed to calculate resistance: the resistance basis determines how much | |
| * overflow will be consumed to achieve maximum resistance, and the resistance factor determines | |
| * the amount of resistance (the larger the resistance factor, the stronger the resistance). | |
| * | |
| * The resistance basis is usually either the size of the component which [swipeable] is applied | |
| * to, or the distance between the minimum and maximum anchors. For a constructor in which the | |
| * resistance basis defaults to the latter, consider using [resistanceConfig]. | |
| * | |
| * You may specify different resistance factors for each bound. Consider using one of the default | |
| * resistance factors in [SwipeableDefaults]: `StandardResistanceFactor` to convey that the user | |
| * has run out of things to see, and `StiffResistanceFactor` to convey that the user cannot swipe | |
| * this right now. Also, you can set either factor to 0 to disable resistance at that bound. | |
| * | |
| * @param basis Specifies the maximum amount of overflow that will be consumed. Must be positive. | |
| * @param factorAtMin The factor by which to scale the resistance at the minimum bound. | |
| * Must not be negative. | |
| * @param factorAtMax The factor by which to scale the resistance at the maximum bound. | |
| * Must not be negative. | |
| */ | |
| @Immutable | |
| class ResistanceConfig( | |
| /*@FloatRange(from = 0.0, fromInclusive = false)*/ | |
| val basis: Float, | |
| /*@FloatRange(from = 0.0)*/ | |
| val factorAtMin: Float = StandardResistanceFactor, | |
| /*@FloatRange(from = 0.0)*/ | |
| val factorAtMax: Float = StandardResistanceFactor | |
| ) { | |
| fun computeResistance(overflow: Float): Float { | |
| val factor = if (overflow < 0) factorAtMin else factorAtMax | |
| if (factor == 0f) return 0f | |
| val progress = (overflow / basis).coerceIn(-1f, 1f) | |
| return basis / factor * sin(progress * PI.toFloat() / 2) | |
| } | |
| override fun equals(other: Any?): Boolean { | |
| if (this === other) return true | |
| if (other !is ResistanceConfig) return false | |
| if (basis != other.basis) return false | |
| if (factorAtMin != other.factorAtMin) return false | |
| if (factorAtMax != other.factorAtMax) return false | |
| return true | |
| } | |
| override fun hashCode(): Int { | |
| var result = basis.hashCode() | |
| result = 31 * result + factorAtMin.hashCode() | |
| result = 31 * result + factorAtMax.hashCode() | |
| return result | |
| } | |
| override fun toString(): String { | |
| return "ResistanceConfig(basis=$basis, factorAtMin=$factorAtMin, factorAtMax=$factorAtMax)" | |
| } | |
| } | |
| /** | |
| * Given an offset x and a set of anchors, return a list of anchors: | |
| * 1. [ ] if the set of anchors is empty, | |
| * 2. [ x' ] if x is equal to one of the anchors, accounting for a small rounding error, where x' | |
| * is x rounded to the exact value of the matching anchor, | |
| * 3. [ min ] if min is the minimum anchor and x < min, | |
| * 4. [ max ] if max is the maximum anchor and x > max, or | |
| * 5. [ a , b ] if a and b are anchors such that a < x < b and b - a is minimal. | |
| */ | |
| private fun findBounds( | |
| offset: Float, | |
| anchors: Set<Float> | |
| ): List<Float> { | |
| // Find the anchors the target lies between with a little bit of rounding error. | |
| val a = anchors.filter { it <= offset + 0.001 }.maxOrNull() | |
| val b = anchors.filter { it >= offset - 0.001 }.minOrNull() | |
| return when { | |
| a == null -> | |
| // case 1 or 3 | |
| listOfNotNull(b) | |
| b == null -> | |
| // case 4 | |
| listOf(a) | |
| a == b -> | |
| // case 2 | |
| // Can't return offset itself here since it might not be exactly equal | |
| // to the anchor, despite being considered an exact match. | |
| listOf(a) | |
| else -> | |
| // case 5 | |
| listOf(a, b) | |
| } | |
| } | |
| private fun computeTarget( | |
| offset: Float, | |
| lastValue: Float, | |
| anchors: Set<Float>, | |
| thresholds: (Float, Float) -> Float, | |
| velocity: Float, | |
| velocityThreshold: Float | |
| ): Float { | |
| val bounds = findBounds(offset, anchors) | |
| return when (bounds.size) { | |
| 0 -> lastValue | |
| 1 -> bounds[0] | |
| else -> { | |
| val lower = bounds[0] | |
| val upper = bounds[1] | |
| if (lastValue <= offset) { | |
| // Swiping from lower to upper (positive). | |
| if (velocity >= velocityThreshold) { | |
| return upper | |
| } else { | |
| val threshold = thresholds(lower, upper) | |
| if (offset < threshold) lower else upper | |
| } | |
| } else { | |
| // Swiping from upper to lower (negative). | |
| if (velocity <= -velocityThreshold) { | |
| return lower | |
| } else { | |
| val threshold = thresholds(upper, lower) | |
| if (offset > threshold) upper else lower | |
| } | |
| } | |
| } | |
| } | |
| } | |
| private fun <T> Map<Float, T>.getOffset(state: T): Float? { | |
| return entries.firstOrNull { it.value == state }?.key | |
| } | |
| /** | |
| * Contains useful defaults for [swipeable] and [SwipeableState]. | |
| */ | |
| object SwipeableDefaults { | |
| /** | |
| * The default animation used by [SwipeableState]. | |
| */ | |
| val AnimationSpec = SpringSpec<Float>() | |
| /** | |
| * The default velocity threshold (1.8 dp per millisecond) used by [swipeable]. | |
| */ | |
| val VelocityThreshold = 125.dp | |
| /** | |
| * A stiff resistance factor which indicates that swiping isn't available right now. | |
| */ | |
| const val StiffResistanceFactor = 20f | |
| /** | |
| * A standard resistance factor which indicates that the user has run out of things to see. | |
| */ | |
| const val StandardResistanceFactor = 10f | |
| /** | |
| * The default resistance config used by [swipeable]. | |
| * | |
| * This returns `null` if there is one anchor. If there are at least two anchors, it returns | |
| * a [ResistanceConfig] with the resistance basis equal to the distance between the two bounds. | |
| */ | |
| fun resistanceConfig( | |
| anchors: Set<Float>, | |
| factorAtMin: Float = StandardResistanceFactor, | |
| factorAtMax: Float = StandardResistanceFactor | |
| ): ResistanceConfig? { | |
| return if (anchors.size <= 1) { | |
| null | |
| } else { | |
| val basis = anchors.maxOrNull()!! - anchors.minOrNull()!! | |
| ResistanceConfig(basis, factorAtMin, factorAtMax) | |
| } | |
| } | |
| } | |
| // temp default nested scroll connection for swipeables which desire as an opt in | |
| // revisit in b/174756744 as all types will have their own specific connection probably | |
| @ExperimentalMaterial3Api | |
| internal val <T> SwipeableState<T>.PreUpPostDownNestedScrollConnection: NestedScrollConnection | |
| get() = object : NestedScrollConnection { | |
| override fun onPreScroll(available: Offset, source: NestedScrollSource): Offset { | |
| val delta = available.toFloat() | |
| return if (delta < 0 && source == NestedScrollSource.Drag) { | |
| performDrag(delta).toOffset() | |
| } else { | |
| Offset.Zero | |
| } | |
| } | |
| override fun onPostScroll( | |
| consumed: Offset, | |
| available: Offset, | |
| source: NestedScrollSource | |
| ): Offset { | |
| return if (source == NestedScrollSource.Drag) { | |
| performDrag(available.toFloat()).toOffset() | |
| } else { | |
| Offset.Zero | |
| } | |
| } | |
| override suspend fun onPreFling(available: Velocity): Velocity { | |
| val toFling = Offset(available.x, available.y).toFloat() | |
| return if (toFling < 0 && offset.value > minBound) { | |
| performFling(velocity = toFling) | |
| // since we go to the anchor with tween settling, consume all for the best UX | |
| available | |
| } else { | |
| Velocity.Zero | |
| } | |
| } | |
| override suspend fun onPostFling(consumed: Velocity, available: Velocity): Velocity { | |
| performFling(velocity = Offset(available.x, available.y).toFloat()) | |
| return available | |
| } | |
| private fun Float.toOffset(): Offset = Offset(0f, this) | |
| private fun Offset.toFloat(): Float = this.y | |
| } | |
How can I use this with BottomSheetNavigator?
hello, don't use it now, because nowadays we finally have a working implementation of modal bottom sheet by Google
https://stackoverflow.com/a/75497791/11278377
@Pasha831 Unfortunately the current Modal Bottom Sheet implementation doesn't work well with BottomSheetNavigator and Jetpack Navigation. Do you have a working implementation of the current implementation with navigation?
no, i don't(
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how do i use this? T~T