| /* |
| * 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.core.gesture |
| |
| import androidx.ui.core.PointerEventPass |
| import androidx.ui.core.PointerInputChange |
| import androidx.ui.core.anyPositionChangeConsumed |
| import androidx.ui.core.changedToDown |
| import androidx.compose.Composable |
| import androidx.compose.ambient |
| import androidx.compose.memo |
| import androidx.compose.unaryPlus |
| import androidx.ui.core.PxPosition |
| import androidx.ui.core.changedToUp |
| import androidx.ui.core.changedToUpIgnoreConsumed |
| import androidx.ui.core.consumeDownChange |
| import androidx.ui.core.CoroutineContextAmbient |
| import androidx.ui.core.IntPxSize |
| import androidx.ui.core.PointerInputWrapper |
| import androidx.ui.core.gesture.util.anyPointersInBounds |
| import androidx.ui.temputils.delay |
| import kotlinx.coroutines.Job |
| import kotlin.coroutines.CoroutineContext |
| |
| // TODO(b/137569202): This bug tracks the note below regarding the need to eventually |
| // improve LongPressGestureDetector. |
| // TODO(b/139020678): Probably has shared functionality with other press based detectors. |
| /** |
| * Responds to a pointer being "down" for an extended amount of time. |
| * |
| * Note: this is likely a temporary, naive, and flawed approach. It is not necessarily guaranteed |
| * to interoperate well with forthcoming behavior related to disambiguation between multi-tap |
| * (double tap, triple tap) and tap. |
| */ |
| @Composable |
| fun LongPressGestureDetector( |
| onLongPress: (PxPosition) -> Unit, |
| children: @Composable() () -> Unit |
| ) { |
| val coroutineContext = +ambient(CoroutineContextAmbient) |
| val recognizer = |
| +memo { LongPressGestureRecognizer(coroutineContext) } |
| recognizer.onLongPress = onLongPress |
| |
| PointerInputWrapper(pointerInputHandler = recognizer.pointerInputHandler, children = children) |
| } |
| |
| internal class LongPressGestureRecognizer( |
| coroutineContext: CoroutineContext |
| ) { |
| lateinit var onLongPress: (PxPosition) -> Unit |
| |
| private enum class State { |
| Idle, Primed, Fired |
| } |
| |
| private var state = State.Idle |
| private val pointerPositions = linkedMapOf<Int, PxPosition>() |
| var longPressTimeout = LongPressTimeout |
| var job: Job? = null |
| |
| val pointerInputHandler = |
| { changes: List<PointerInputChange>, pass: PointerEventPass, bounds: IntPxSize -> |
| |
| var changesToReturn = changes |
| |
| if (pass == PointerEventPass.InitialDown && state == State.Fired) { |
| // If we are in the Fired state, we dispatched the long press event and pointers are still down so we |
| // should consume any up events to prevent other gesture detectors from responding to up. |
| changesToReturn = changesToReturn.map { |
| if (it.changedToUp()) { |
| it.consumeDownChange() |
| } else { |
| it |
| } |
| } |
| } |
| |
| if (pass == PointerEventPass.PostUp) { |
| if (state == State.Idle && changes.all { it.changedToDown() }) { |
| // If we have not yet started and all of the changes changed to down, we are |
| // starting. |
| job = delay(longPressTimeout, coroutineContext) { |
| onLongPress.invoke(pointerPositions.asIterable().first().value) |
| state = State.Fired |
| } |
| pointerPositions.clear() |
| state = State.Primed |
| } else if (state != State.Idle && changes.all { it.changedToUpIgnoreConsumed() }) { |
| // If we have started and all of the changes changed to up, we are stopping. |
| reset() |
| } else if (!changesToReturn.anyPointersInBounds(bounds)) { |
| // If none of the pointers are in bounds of our bounds, we should reset and wait |
| // till all pointers are changing to down to "prime" again. |
| reset() |
| } |
| |
| if (state == State.Primed) { |
| // If we are primed, for all down pointers, keep track of their current positions, and for all |
| // other pointers, remove their tracked information. |
| changes.forEach { |
| if (it.current.down) { |
| pointerPositions[it.id] = it.current.position!! |
| } else { |
| pointerPositions.remove(it.id) |
| } |
| } |
| } |
| } |
| |
| if (pass == PointerEventPass.PostDown && |
| state != State.Idle && |
| changes.any { it.anyPositionChangeConsumed() } |
| ) { |
| // If we are primed, reset so we don't fire. |
| // If we are fired, reset to idle so we don't block up events that still fire after |
| // dragging (like flinging). |
| reset() |
| } |
| |
| changesToReturn |
| } |
| |
| private fun reset() { |
| job?.cancel() |
| state = State.Idle |
| } |
| } |