mirror of https://github.com/tasks/tasks
You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
792 lines
30 KiB
Kotlin
792 lines
30 KiB
Kotlin
/*
|
|
* Copyright 2022 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 org.tasks.compose.drawer
|
|
|
|
/**
|
|
* This is a copy of androidx.compose.foundation.gestures.AnchoredDraggable until that API is
|
|
* promoted to stable in foundation. Any changes there should be replicated here.
|
|
*/
|
|
import androidx.annotation.FloatRange
|
|
import androidx.compose.animation.core.AnimationSpec
|
|
import androidx.compose.animation.core.SpringSpec
|
|
import androidx.compose.animation.core.animate
|
|
import androidx.compose.foundation.MutatePriority
|
|
import androidx.compose.foundation.gestures.DragScope
|
|
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.foundation.layout.offset
|
|
import androidx.compose.material3.ExperimentalMaterial3Api
|
|
import androidx.compose.runtime.Stable
|
|
import androidx.compose.runtime.derivedStateOf
|
|
import androidx.compose.runtime.getValue
|
|
import androidx.compose.runtime.mutableFloatStateOf
|
|
import androidx.compose.runtime.mutableStateOf
|
|
import androidx.compose.runtime.saveable.Saver
|
|
import androidx.compose.runtime.setValue
|
|
import androidx.compose.runtime.snapshotFlow
|
|
import androidx.compose.runtime.structuralEqualityPolicy
|
|
import androidx.compose.ui.Modifier
|
|
import kotlinx.coroutines.CancellationException
|
|
import kotlinx.coroutines.CoroutineStart
|
|
import kotlinx.coroutines.Job
|
|
import kotlinx.coroutines.cancel
|
|
import kotlinx.coroutines.coroutineScope
|
|
import kotlinx.coroutines.launch
|
|
import kotlin.math.abs
|
|
|
|
/**
|
|
* Structure that represents the anchors of a [AnchoredDraggableState].
|
|
*
|
|
* See the DraggableAnchors factory method to construct drag anchors using a default implementation.
|
|
*/
|
|
@ExperimentalMaterial3Api
|
|
internal interface DraggableAnchors<T> {
|
|
|
|
/**
|
|
* Get the anchor position for an associated [value]
|
|
*
|
|
* @return The position of the anchor, or [Float.NaN] if the anchor does not exist
|
|
*/
|
|
fun positionOf(value: T): Float
|
|
|
|
/**
|
|
* Whether there is an anchor position associated with the [value]
|
|
*
|
|
* @param value The value to look up
|
|
* @return true if there is an anchor for this value, false if there is no anchor for this value
|
|
*/
|
|
fun hasAnchorFor(value: T): Boolean
|
|
|
|
/**
|
|
* Find the closest anchor to the [position].
|
|
*
|
|
* @param position The position to start searching from
|
|
*
|
|
* @return The closest anchor or null if the anchors are empty
|
|
*/
|
|
fun closestAnchor(position: Float): T?
|
|
|
|
/**
|
|
* Find the closest anchor to the [position], in the specified direction.
|
|
*
|
|
* @param position The position to start searching from
|
|
* @param searchUpwards Whether to search upwards from the current position or downwards
|
|
*
|
|
* @return The closest anchor or null if the anchors are empty
|
|
*/
|
|
fun closestAnchor(position: Float, searchUpwards: Boolean): T?
|
|
|
|
/**
|
|
* The smallest anchor, or [Float.NEGATIVE_INFINITY] if the anchors are empty.
|
|
*/
|
|
fun minAnchor(): Float
|
|
|
|
/**
|
|
* The biggest anchor, or [Float.POSITIVE_INFINITY] if the anchors are empty.
|
|
*/
|
|
fun maxAnchor(): Float
|
|
|
|
/**
|
|
* The amount of anchors
|
|
*/
|
|
val size: Int
|
|
}
|
|
|
|
/**
|
|
* [DraggableAnchorsConfig] stores a mutable configuration anchors, comprised of values of [T] and
|
|
* corresponding [Float] positions. This [DraggableAnchorsConfig] is used to construct an immutable
|
|
* [DraggableAnchors] instance later on.
|
|
*/
|
|
@ExperimentalMaterial3Api
|
|
internal class DraggableAnchorsConfig<T> {
|
|
|
|
internal val anchors = mutableMapOf<T, Float>()
|
|
|
|
/**
|
|
* Set the anchor position for [this] anchor.
|
|
*
|
|
* @param position The anchor position.
|
|
*/
|
|
@Suppress("BuilderSetStyle")
|
|
infix fun T.at(position: Float) {
|
|
anchors[this] = position
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Create a new [DraggableAnchors] instance using a builder function.
|
|
*
|
|
* @param builder A function with a [DraggableAnchorsConfig] that offers APIs to configure anchors
|
|
* @return A new [DraggableAnchors] instance with the anchor positions set by the `builder`
|
|
* function.
|
|
*/
|
|
@ExperimentalMaterial3Api
|
|
internal fun <T : Any> DraggableAnchors(
|
|
builder: DraggableAnchorsConfig<T>.() -> Unit
|
|
): DraggableAnchors<T> = MapDraggableAnchors(DraggableAnchorsConfig<T>().apply(builder).anchors)
|
|
|
|
/**
|
|
* Enable drag gestures between a set of predefined values.
|
|
*
|
|
* When a drag is detected, the offset of the [AnchoredDraggableState] will be updated with the drag
|
|
* delta. You should use this offset to move your content accordingly (see [Modifier.offset]).
|
|
* When the drag ends, the offset will be animated to one of the anchors and when that anchor is
|
|
* reached, the value of the [AnchoredDraggableState] will also be updated to the value
|
|
* corresponding to the new anchor.
|
|
*
|
|
* Dragging is constrained between the minimum and maximum anchors.
|
|
*
|
|
* @param state The associated [AnchoredDraggableState].
|
|
* @param orientation The orientation in which the [anchoredDraggable] can be dragged.
|
|
* @param enabled Whether this [anchoredDraggable] is enabled and should react to the user's input.
|
|
* @param reverseDirection Whether to reverse the direction of the drag, so a top to bottom
|
|
* drag will behave like bottom to top, and a left to right drag will behave like right to left.
|
|
* @param interactionSource Optional [MutableInteractionSource] that will passed on to
|
|
* the internal [Modifier.draggable].
|
|
*/
|
|
@ExperimentalMaterial3Api
|
|
internal fun <T> Modifier.anchoredDraggable(
|
|
state: AnchoredDraggableState<T>,
|
|
orientation: Orientation,
|
|
enabled: Boolean = true,
|
|
reverseDirection: Boolean = false,
|
|
interactionSource: MutableInteractionSource? = null
|
|
) = draggable(
|
|
state = state.draggableState,
|
|
orientation = orientation,
|
|
enabled = enabled,
|
|
interactionSource = interactionSource,
|
|
reverseDirection = reverseDirection,
|
|
startDragImmediately = state.isAnimationRunning,
|
|
onDragStopped = { velocity -> launch { state.settle(velocity) } }
|
|
)
|
|
|
|
/**
|
|
* Scope used for suspending anchored drag blocks. Allows to set [AnchoredDraggableState.offset] to
|
|
* a new value.
|
|
*
|
|
* @see [AnchoredDraggableState.anchoredDrag] to learn how to start the anchored drag and get the
|
|
* access to this scope.
|
|
*/
|
|
@ExperimentalMaterial3Api
|
|
internal interface AnchoredDragScope {
|
|
/**
|
|
* Assign a new value for an offset value for [AnchoredDraggableState].
|
|
*
|
|
* @param newOffset new value for [AnchoredDraggableState.offset].
|
|
* @param lastKnownVelocity last known velocity (if known)
|
|
*/
|
|
fun dragTo(
|
|
newOffset: Float,
|
|
lastKnownVelocity: Float = 0f
|
|
)
|
|
}
|
|
|
|
/**
|
|
* State of the [anchoredDraggable] modifier.
|
|
* Use the constructor overload with anchors if the anchors are defined in composition, or update
|
|
* the anchors using [updateAnchors].
|
|
*
|
|
* This contains necessary information about any ongoing drag or animation and provides methods
|
|
* to change the state either immediately or by starting an animation.
|
|
*
|
|
* @param initialValue The initial value of the state.
|
|
* @param positionalThreshold The positional threshold, in px, to be used when calculating the
|
|
* target state while a drag is in progress and when settling after the drag ends. This is the
|
|
* distance from the start of a transition. It will be, depending on the direction of the
|
|
* interaction, added or subtracted from/to the origin offset. It should always be a positive value.
|
|
* @param velocityThreshold The velocity threshold (in px per second) that the end velocity has to
|
|
* exceed in order to animate to the next state, even if the [positionalThreshold] has not been
|
|
* reached.
|
|
* @param animationSpec The default animation that will be used to animate to a new state.
|
|
* @param confirmValueChange Optional callback invoked to confirm or veto a pending state change.
|
|
*/
|
|
@Stable
|
|
@ExperimentalMaterial3Api
|
|
internal class AnchoredDraggableState<T>(
|
|
initialValue: T,
|
|
internal val positionalThreshold: (totalDistance: Float) -> Float,
|
|
internal val velocityThreshold: () -> Float,
|
|
val animationSpec: AnimationSpec<Float>,
|
|
internal val confirmValueChange: (newValue: T) -> Boolean = { true }
|
|
) {
|
|
|
|
/**
|
|
* Construct an [AnchoredDraggableState] instance with anchors.
|
|
*
|
|
* @param initialValue The initial value of the state.
|
|
* @param anchors The anchors of the state. Use [updateAnchors] to update the anchors later.
|
|
* @param animationSpec The default animation that will be used to animate to a new state.
|
|
* @param confirmValueChange Optional callback invoked to confirm or veto a pending state
|
|
* change.
|
|
* @param positionalThreshold The positional threshold, in px, to be used when calculating the
|
|
* target state while a drag is in progress and when settling after the drag ends. This is the
|
|
* distance from the start of a transition. It will be, depending on the direction of the
|
|
* interaction, added or subtracted from/to the origin offset. It should always be a positive
|
|
* value.
|
|
* @param velocityThreshold The velocity threshold (in px per second) that the end velocity has
|
|
* to exceed in order to animate to the next state, even if the [positionalThreshold] has not
|
|
* been reached.
|
|
*/
|
|
@ExperimentalMaterial3Api
|
|
constructor(
|
|
initialValue: T,
|
|
anchors: DraggableAnchors<T>,
|
|
positionalThreshold: (totalDistance: Float) -> Float,
|
|
velocityThreshold: () -> Float,
|
|
animationSpec: AnimationSpec<Float>,
|
|
confirmValueChange: (newValue: T) -> Boolean = { true }
|
|
) : this(
|
|
initialValue,
|
|
positionalThreshold,
|
|
velocityThreshold,
|
|
animationSpec,
|
|
confirmValueChange
|
|
) {
|
|
this.anchors = anchors
|
|
trySnapTo(initialValue)
|
|
}
|
|
|
|
private val dragMutex = InternalMutatorMutex()
|
|
|
|
internal val draggableState = object : DraggableState {
|
|
|
|
private val dragScope = object : DragScope {
|
|
override fun dragBy(pixels: Float) {
|
|
with(anchoredDragScope) {
|
|
dragTo(newOffsetForDelta(pixels))
|
|
}
|
|
}
|
|
}
|
|
|
|
override suspend fun drag(
|
|
dragPriority: MutatePriority,
|
|
block: suspend DragScope.() -> Unit
|
|
) {
|
|
this@AnchoredDraggableState.anchoredDrag(dragPriority) {
|
|
with(dragScope) { block() }
|
|
}
|
|
}
|
|
|
|
override fun dispatchRawDelta(delta: Float) {
|
|
this@AnchoredDraggableState.dispatchRawDelta(delta)
|
|
}
|
|
}
|
|
|
|
/**
|
|
* The current value of the [AnchoredDraggableState].
|
|
*/
|
|
var currentValue: T by mutableStateOf(initialValue)
|
|
private set
|
|
|
|
/**
|
|
* The target value. This is the closest value to the current offset, taking into account
|
|
* positional thresholds. If no interactions like animations or drags are in progress, this
|
|
* will be the current value.
|
|
*/
|
|
val targetValue: T by derivedStateOf {
|
|
dragTarget ?: run {
|
|
val currentOffset = offset
|
|
if (!currentOffset.isNaN()) {
|
|
computeTarget(currentOffset, currentValue, velocity = 0f)
|
|
} else currentValue
|
|
}
|
|
}
|
|
|
|
/**
|
|
* The closest value in the swipe direction from the current offset, not considering thresholds.
|
|
* If an [anchoredDrag] is in progress, this will be the target of that anchoredDrag (if
|
|
* specified).
|
|
*/
|
|
internal val closestValue: T by derivedStateOf {
|
|
dragTarget ?: run {
|
|
val currentOffset = offset
|
|
if (!currentOffset.isNaN()) {
|
|
computeTargetWithoutThresholds(currentOffset, currentValue)
|
|
} else currentValue
|
|
}
|
|
}
|
|
|
|
/**
|
|
* The current offset, or [Float.NaN] if it has not been initialized yet.
|
|
*
|
|
* The offset will be initialized when the anchors are first set through [updateAnchors].
|
|
*
|
|
* Strongly consider using [requireOffset] which will throw if the offset is read before it is
|
|
* initialized. This helps catch issues early in your workflow.
|
|
*/
|
|
var offset: Float by mutableFloatStateOf(Float.NaN)
|
|
private set
|
|
|
|
/**
|
|
* Require the current offset.
|
|
*
|
|
* @see offset
|
|
*
|
|
* @throws IllegalStateException If the offset has not been initialized yet
|
|
*/
|
|
fun requireOffset(): Float {
|
|
check(!offset.isNaN()) {
|
|
"The offset was read before being initialized. Did you access the offset in a phase " +
|
|
"before layout, like effects or composition?"
|
|
}
|
|
return offset
|
|
}
|
|
|
|
/**
|
|
* Whether an animation is currently in progress.
|
|
*/
|
|
val isAnimationRunning: Boolean get() = dragTarget != null
|
|
|
|
/**
|
|
* The fraction of the progress going from [currentValue] to [closestValue], within [0f..1f]
|
|
* bounds, or 1f if the [AnchoredDraggableState] is in a settled state.
|
|
*/
|
|
@get:FloatRange(from = 0.0, to = 1.0)
|
|
val progress: Float by derivedStateOf(structuralEqualityPolicy()) {
|
|
val a = anchors.positionOf(currentValue)
|
|
val b = anchors.positionOf(closestValue)
|
|
val distance = abs(b - a)
|
|
if (!distance.isNaN() && distance > 1e-6f) {
|
|
val progress = (this.requireOffset() - a) / (b - a)
|
|
// If we are very close to 0f or 1f, we round to the closest
|
|
if (progress < 1e-6f) 0f else if (progress > 1 - 1e-6f) 1f else progress
|
|
} else 1f
|
|
}
|
|
|
|
/**
|
|
* The velocity of the last known animation. Gets reset to 0f when an animation completes
|
|
* successfully, but does not get reset when an animation gets interrupted.
|
|
* You can use this value to provide smooth reconciliation behavior when re-targeting an
|
|
* animation.
|
|
*/
|
|
var lastVelocity: Float by mutableFloatStateOf(0f)
|
|
private set
|
|
|
|
private var dragTarget: T? by mutableStateOf(null)
|
|
|
|
var anchors: DraggableAnchors<T> by mutableStateOf(emptyDraggableAnchors())
|
|
private set
|
|
|
|
/**
|
|
* Update the anchors. If there is no ongoing [anchoredDrag] operation, snap to the [newTarget],
|
|
* otherwise restart the ongoing [anchoredDrag] operation (e.g. an animation) with the new
|
|
* anchors.
|
|
*
|
|
* <b>If your anchors depend on the size of the layout, updateAnchors should be called in the
|
|
* layout (placement) phase, e.g. through Modifier.onSizeChanged.</b> This ensures that the
|
|
* state is set up within the same frame.
|
|
* For static anchors, or anchors with different data dependencies, [updateAnchors] is safe to
|
|
* be called from side effects or layout.
|
|
*
|
|
* @param newAnchors The new anchors.
|
|
* @param newTarget The new target, by default the closest anchor or the current target if there
|
|
* are no anchors.
|
|
*/
|
|
fun updateAnchors(
|
|
newAnchors: DraggableAnchors<T>,
|
|
newTarget: T = if (!offset.isNaN()) {
|
|
newAnchors.closestAnchor(offset) ?: targetValue
|
|
} else targetValue
|
|
) {
|
|
if (anchors != newAnchors) {
|
|
anchors = newAnchors
|
|
// Attempt to snap. If nobody is holding the lock, we can immediately update the offset.
|
|
// If anybody is holding the lock, we send a signal to restart the ongoing work with the
|
|
// updated anchors.
|
|
val snapSuccessful = trySnapTo(newTarget)
|
|
if (!snapSuccessful) {
|
|
dragTarget = newTarget
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Find the closest anchor, taking into account the [velocityThreshold] and
|
|
* [positionalThreshold], and settle at it with an animation.
|
|
*
|
|
* If the [velocity] is lower than the [velocityThreshold], the closest anchor by distance and
|
|
* [positionalThreshold] will be the target. If the [velocity] is higher than the
|
|
* [velocityThreshold], the [positionalThreshold] will <b>not</b> be considered and the next
|
|
* anchor in the direction indicated by the sign of the [velocity] will be the target.
|
|
*/
|
|
suspend fun settle(velocity: Float) {
|
|
val previousValue = this.currentValue
|
|
val targetValue = computeTarget(
|
|
offset = requireOffset(),
|
|
currentValue = previousValue,
|
|
velocity = velocity
|
|
)
|
|
if (confirmValueChange(targetValue)) {
|
|
animateTo(targetValue, velocity)
|
|
} else {
|
|
// If the user vetoed the state change, rollback to the previous state.
|
|
animateTo(previousValue, velocity)
|
|
}
|
|
}
|
|
|
|
private fun computeTarget(
|
|
offset: Float,
|
|
currentValue: T,
|
|
velocity: Float
|
|
): T {
|
|
val currentAnchors = anchors
|
|
val currentAnchorPosition = currentAnchors.positionOf(currentValue)
|
|
val velocityThresholdPx = velocityThreshold()
|
|
return if (currentAnchorPosition == offset || currentAnchorPosition.isNaN()) {
|
|
currentValue
|
|
} else if (currentAnchorPosition < offset) {
|
|
// Swiping from lower to upper (positive).
|
|
if (velocity >= velocityThresholdPx) {
|
|
currentAnchors.closestAnchor(offset, true)!!
|
|
} else {
|
|
val upper = currentAnchors.closestAnchor(offset, true)!!
|
|
val distance = abs(currentAnchors.positionOf(upper) - currentAnchorPosition)
|
|
val relativeThreshold = abs(positionalThreshold(distance))
|
|
val absoluteThreshold = abs(currentAnchorPosition + relativeThreshold)
|
|
if (offset < absoluteThreshold) currentValue else upper
|
|
}
|
|
} else {
|
|
// Swiping from upper to lower (negative).
|
|
if (velocity <= -velocityThresholdPx) {
|
|
currentAnchors.closestAnchor(offset, false)!!
|
|
} else {
|
|
val lower = currentAnchors.closestAnchor(offset, false)!!
|
|
val distance = abs(currentAnchorPosition - currentAnchors.positionOf(lower))
|
|
val relativeThreshold = abs(positionalThreshold(distance))
|
|
val absoluteThreshold = abs(currentAnchorPosition - relativeThreshold)
|
|
if (offset < 0) {
|
|
// For negative offsets, larger absolute thresholds are closer to lower anchors
|
|
// than smaller ones.
|
|
if (abs(offset) < absoluteThreshold) currentValue else lower
|
|
} else {
|
|
if (offset > absoluteThreshold) currentValue else lower
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
private fun computeTargetWithoutThresholds(
|
|
offset: Float,
|
|
currentValue: T,
|
|
): T {
|
|
val currentAnchors = anchors
|
|
val currentAnchorPosition = currentAnchors.positionOf(currentValue)
|
|
return if (currentAnchorPosition == offset || currentAnchorPosition.isNaN()) {
|
|
currentValue
|
|
} else if (currentAnchorPosition < offset) {
|
|
currentAnchors.closestAnchor(offset, true) ?: currentValue
|
|
} else {
|
|
currentAnchors.closestAnchor(offset, false) ?: currentValue
|
|
}
|
|
}
|
|
|
|
private val anchoredDragScope: AnchoredDragScope = object : AnchoredDragScope {
|
|
override fun dragTo(newOffset: Float, lastKnownVelocity: Float) {
|
|
offset = newOffset
|
|
lastVelocity = lastKnownVelocity
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Call this function to take control of drag logic and perform anchored drag with the latest
|
|
* anchors.
|
|
*
|
|
* All actions that change the [offset] of this [AnchoredDraggableState] must be performed
|
|
* within an [anchoredDrag] block (even if they don't call any other methods on this object)
|
|
* in order to guarantee that mutual exclusion is enforced.
|
|
*
|
|
* If [anchoredDrag] is called from elsewhere with the [dragPriority] higher or equal to ongoing
|
|
* drag, the ongoing drag will be cancelled.
|
|
*
|
|
* <b>If the [anchors] change while the [block] is being executed, it will be cancelled and
|
|
* re-executed with the latest anchors and target.</b> This allows you to target the correct
|
|
* state.
|
|
*
|
|
* @param dragPriority of the drag operation
|
|
* @param block perform anchored drag given the current anchor provided
|
|
*/
|
|
suspend fun anchoredDrag(
|
|
dragPriority: MutatePriority = MutatePriority.Default,
|
|
block: suspend AnchoredDragScope.(anchors: DraggableAnchors<T>) -> Unit
|
|
) {
|
|
try {
|
|
dragMutex.mutate(dragPriority) {
|
|
restartable(inputs = { anchors }) { latestAnchors ->
|
|
anchoredDragScope.block(latestAnchors)
|
|
}
|
|
}
|
|
} finally {
|
|
val closest = anchors.closestAnchor(offset)
|
|
if (closest != null &&
|
|
abs(offset - anchors.positionOf(closest)) <= 0.5f &&
|
|
confirmValueChange.invoke(closest)
|
|
) {
|
|
currentValue = closest
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Call this function to take control of drag logic and perform anchored drag with the latest
|
|
* anchors and target.
|
|
*
|
|
* All actions that change the [offset] of this [AnchoredDraggableState] must be performed
|
|
* within an [anchoredDrag] block (even if they don't call any other methods on this object)
|
|
* in order to guarantee that mutual exclusion is enforced.
|
|
*
|
|
* This overload allows the caller to hint the target value that this [anchoredDrag] is intended
|
|
* to arrive to. This will set [AnchoredDraggableState.targetValue] to provided value so
|
|
* consumers can reflect it in their UIs.
|
|
*
|
|
* <b>If the [anchors] or [AnchoredDraggableState.targetValue] change while the [block] is being
|
|
* executed, it will be cancelled and re-executed with the latest anchors and target.</b> This
|
|
* allows you to target the correct state.
|
|
*
|
|
* If [anchoredDrag] is called from elsewhere with the [dragPriority] higher or equal to ongoing
|
|
* drag, the ongoing drag will be cancelled.
|
|
*
|
|
* @param targetValue hint the target value that this [anchoredDrag] is intended to arrive to
|
|
* @param dragPriority of the drag operation
|
|
* @param block perform anchored drag given the current anchor provided
|
|
*/
|
|
suspend fun anchoredDrag(
|
|
targetValue: T,
|
|
dragPriority: MutatePriority = MutatePriority.Default,
|
|
block: suspend AnchoredDragScope.(anchors: DraggableAnchors<T>, targetValue: T) -> Unit
|
|
) {
|
|
if (anchors.hasAnchorFor(targetValue)) {
|
|
try {
|
|
dragMutex.mutate(dragPriority) {
|
|
dragTarget = targetValue
|
|
restartable(
|
|
inputs = { anchors to this@AnchoredDraggableState.targetValue }
|
|
) { (latestAnchors, latestTarget) ->
|
|
anchoredDragScope.block(latestAnchors, latestTarget)
|
|
}
|
|
}
|
|
} finally {
|
|
dragTarget = null
|
|
val closest = anchors.closestAnchor(offset)
|
|
if (closest != null &&
|
|
abs(offset - anchors.positionOf(closest)) <= 0.5f &&
|
|
confirmValueChange.invoke(closest)
|
|
) {
|
|
currentValue = closest
|
|
}
|
|
}
|
|
} else {
|
|
// Todo: b/283467401, revisit this behavior
|
|
currentValue = targetValue
|
|
}
|
|
}
|
|
|
|
internal fun newOffsetForDelta(delta: Float) =
|
|
((if (offset.isNaN()) 0f else offset) + delta)
|
|
.coerceIn(anchors.minAnchor(), anchors.maxAnchor())
|
|
|
|
/**
|
|
* Drag by the [delta], coerce it in the bounds and dispatch it to the [AnchoredDraggableState].
|
|
*
|
|
* @return The delta the consumed by the [AnchoredDraggableState]
|
|
*/
|
|
fun dispatchRawDelta(delta: Float): Float {
|
|
val newOffset = newOffsetForDelta(delta)
|
|
val oldOffset = if (offset.isNaN()) 0f else offset
|
|
offset = newOffset
|
|
return newOffset - oldOffset
|
|
}
|
|
|
|
/**
|
|
* Attempt to snap synchronously. Snapping can happen synchronously when there is no other drag
|
|
* transaction like a drag or an animation is progress. If there is another interaction in
|
|
* progress, the suspending [snapTo] overload needs to be used.
|
|
*
|
|
* @return true if the synchronous snap was successful, or false if we couldn't snap synchronous
|
|
*/
|
|
private fun trySnapTo(targetValue: T): Boolean = dragMutex.tryMutate {
|
|
with(anchoredDragScope) {
|
|
val targetOffset = anchors.positionOf(targetValue)
|
|
if (!targetOffset.isNaN()) {
|
|
dragTo(targetOffset)
|
|
dragTarget = null
|
|
}
|
|
currentValue = targetValue
|
|
}
|
|
}
|
|
|
|
companion object {
|
|
/**
|
|
* The default [Saver] implementation for [AnchoredDraggableState].
|
|
*/
|
|
@ExperimentalMaterial3Api
|
|
fun <T : Any> Saver(
|
|
animationSpec: AnimationSpec<Float>,
|
|
confirmValueChange: (T) -> Boolean,
|
|
positionalThreshold: (distance: Float) -> Float,
|
|
velocityThreshold: () -> Float,
|
|
) = Saver<AnchoredDraggableState<T>, T>(
|
|
save = { it.currentValue },
|
|
restore = {
|
|
AnchoredDraggableState(
|
|
initialValue = it,
|
|
animationSpec = animationSpec,
|
|
confirmValueChange = confirmValueChange,
|
|
positionalThreshold = positionalThreshold,
|
|
velocityThreshold = velocityThreshold
|
|
)
|
|
}
|
|
)
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Snap to a [targetValue] without any animation.
|
|
* If the [targetValue] is not in the set of anchors, the [AnchoredDraggableState.currentValue] will
|
|
* be updated to the [targetValue] without updating the offset.
|
|
*
|
|
* @throws CancellationException if the interaction interrupted by another interaction like a
|
|
* gesture interaction or another programmatic interaction like a [animateTo] or [snapTo] call.
|
|
*
|
|
* @param targetValue The target value of the animation
|
|
*/
|
|
@ExperimentalMaterial3Api
|
|
internal suspend fun <T> AnchoredDraggableState<T>.snapTo(targetValue: T) {
|
|
anchoredDrag(targetValue = targetValue) { anchors, latestTarget ->
|
|
val targetOffset = anchors.positionOf(latestTarget)
|
|
if (!targetOffset.isNaN()) dragTo(targetOffset)
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Animate to a [targetValue].
|
|
* If the [targetValue] is not in the set of anchors, the [AnchoredDraggableState.currentValue] will
|
|
* be updated to the [targetValue] without updating the offset.
|
|
*
|
|
* @throws CancellationException if the interaction interrupted by another interaction like a
|
|
* gesture interaction or another programmatic interaction like a [animateTo] or [snapTo] call.
|
|
*
|
|
* @param targetValue The target value of the animation
|
|
* @param velocity The velocity the animation should start with
|
|
*/
|
|
@ExperimentalMaterial3Api
|
|
internal suspend fun <T> AnchoredDraggableState<T>.animateTo(
|
|
targetValue: T,
|
|
velocity: Float = this.lastVelocity,
|
|
) {
|
|
anchoredDrag(targetValue = targetValue) { anchors, latestTarget ->
|
|
val targetOffset = anchors.positionOf(latestTarget)
|
|
if (!targetOffset.isNaN()) {
|
|
var prev = if (offset.isNaN()) 0f else offset
|
|
animate(prev, targetOffset, velocity, animationSpec) { value, velocity ->
|
|
// Our onDrag coerces the value within the bounds, but an animation may
|
|
// overshoot, for example a spring animation or an overshooting interpolator
|
|
// We respect the user's intention and allow the overshoot, but still use
|
|
// DraggableState's drag for its mutex.
|
|
dragTo(value, velocity)
|
|
prev = value
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Contains useful defaults for [anchoredDraggable] and [AnchoredDraggableState].
|
|
*/
|
|
@Stable
|
|
@ExperimentalMaterial3Api
|
|
internal object AnchoredDraggableDefaults {
|
|
/**
|
|
* The default animation used by [AnchoredDraggableState].
|
|
*/
|
|
@get:ExperimentalMaterial3Api
|
|
@Suppress("OPT_IN_MARKER_ON_WRONG_TARGET")
|
|
@ExperimentalMaterial3Api
|
|
val AnimationSpec = SpringSpec<Float>()
|
|
}
|
|
|
|
private class AnchoredDragFinishedSignal : CancellationException() {
|
|
override fun fillInStackTrace(): Throwable {
|
|
stackTrace = emptyArray()
|
|
return this
|
|
}
|
|
}
|
|
|
|
private suspend fun <I> restartable(inputs: () -> I, block: suspend (I) -> Unit) {
|
|
try {
|
|
coroutineScope {
|
|
var previousDrag: Job? = null
|
|
snapshotFlow(inputs)
|
|
.collect { latestInputs ->
|
|
previousDrag?.apply {
|
|
cancel(AnchoredDragFinishedSignal())
|
|
join()
|
|
}
|
|
previousDrag = launch(start = CoroutineStart.UNDISPATCHED) {
|
|
block(latestInputs)
|
|
this@coroutineScope.cancel(AnchoredDragFinishedSignal())
|
|
}
|
|
}
|
|
}
|
|
} catch (anchoredDragFinished: AnchoredDragFinishedSignal) {
|
|
// Ignored
|
|
}
|
|
}
|
|
|
|
private fun <T> emptyDraggableAnchors() = MapDraggableAnchors<T>(emptyMap())
|
|
|
|
@OptIn(ExperimentalMaterial3Api::class)
|
|
private class MapDraggableAnchors<T>(private val anchors: Map<T, Float>) : DraggableAnchors<T> {
|
|
|
|
override fun positionOf(value: T): Float = anchors[value] ?: Float.NaN
|
|
override fun hasAnchorFor(value: T) = anchors.containsKey(value)
|
|
|
|
override fun closestAnchor(position: Float): T? = anchors.minByOrNull {
|
|
abs(position - it.value)
|
|
}?.key
|
|
|
|
override fun closestAnchor(
|
|
position: Float,
|
|
searchUpwards: Boolean
|
|
): T? {
|
|
return anchors.minByOrNull { (_, anchor) ->
|
|
val delta = if (searchUpwards) anchor - position else position - anchor
|
|
if (delta < 0) Float.POSITIVE_INFINITY else delta
|
|
}?.key
|
|
}
|
|
|
|
override fun minAnchor() = anchors.values.minOrNull() ?: Float.NaN
|
|
|
|
override fun maxAnchor() = anchors.values.maxOrNull() ?: Float.NaN
|
|
|
|
override val size: Int
|
|
get() = anchors.size
|
|
|
|
override fun equals(other: Any?): Boolean {
|
|
if (this === other) return true
|
|
if (other !is MapDraggableAnchors<*>) return false
|
|
|
|
return anchors == other.anchors
|
|
}
|
|
|
|
override fun hashCode() = 31 * anchors.hashCode()
|
|
|
|
override fun toString() = "MapDraggableAnchors($anchors)"
|
|
}
|