| /* |
| * 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. |
| */ |
| |
| package androidx.compose.foundation |
| |
| import androidx.compose.Stable |
| import androidx.compose.State |
| import androidx.compose.getValue |
| import androidx.compose.mutableStateOf |
| import androidx.compose.setValue |
| import androidx.ui.geometry.Offset |
| |
| /** |
| * InteractionState represents a [Set] of [Interaction]s present on a given component. This |
| * allows you to build higher level components comprised of lower level interactions such as |
| * [clickable] and [androidx.compose.foundation.gestures.draggable], and react to [Interaction] |
| * changes driven by these components in one place. For [Interaction]s with an associated |
| * position, such as [Interaction.Pressed], you can retrieve this position by using |
| * [interactionPositionFor]. |
| * |
| * Creating an [InteractionState] and passing it to these lower level interactions will cause a |
| * recomposition when there are changes to the state of [Interaction], such as when a [clickable] |
| * becomes [Interaction.Pressed]. |
| * |
| * @sample androidx.compose.foundation.samples.InteractionStateSample |
| */ |
| @Stable |
| class InteractionState : State<Set<Interaction>> { |
| |
| private var map: Map<Interaction, Offset?> by mutableStateOf(emptyMap()) |
| |
| override val value: Set<Interaction> |
| get() = map.keys |
| |
| /** |
| * Adds the provided [interaction] to this InteractionState. |
| * Since InteractionState represents a [Set], duplicate [interaction]s will not be added, and |
| * hence will not cause a recomposition. |
| * |
| * @param interaction interaction to add |
| * @param position position at which the interaction occurred, if relevant. For example, for |
| * [Interaction.Pressed], this will be the position of the pointer input that triggered the |
| * pressed state. |
| */ |
| fun addInteraction(interaction: Interaction, position: Offset? = null) { |
| if (interaction !in this) map = map + (interaction to position) |
| } |
| |
| /** |
| * Removes the provided [interaction], if it is present, from this InteractionState. |
| */ |
| fun removeInteraction(interaction: Interaction) { |
| if (interaction in this) map = map - interaction |
| } |
| |
| /** |
| * Returns the position for a particular [Interaction], if there is a position associated |
| * with the interaction. |
| * |
| * @return position associated with the interaction, or `null` if the interaction is not |
| * present in this state, or there is no associated position with the given interaction. |
| */ |
| fun interactionPositionFor(interaction: Interaction): Offset? = map[interaction] |
| |
| /** |
| * @return whether the provided [interaction] exists inside this InteractionState. |
| */ |
| operator fun contains(interaction: Interaction): Boolean = map.contains(interaction) |
| } |