| /* |
| * 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.ui.core.demos.gestures |
| |
| import androidx.compose.Composable |
| import androidx.compose.remember |
| import androidx.compose.state |
| import androidx.ui.core.Alignment |
| import androidx.ui.core.Modifier |
| import androidx.ui.core.PointerEventPass |
| import androidx.ui.core.PointerInputChange |
| import androidx.ui.core.changedToDownIgnoreConsumed |
| import androidx.ui.core.changedToUpIgnoreConsumed |
| import androidx.ui.core.composed |
| import androidx.ui.core.pointerinput.PointerInputFilter |
| import androidx.ui.core.pointerinput.PointerInputModifier |
| import androidx.compose.foundation.Box |
| import androidx.compose.foundation.lazy.LazyColumnItems |
| import androidx.compose.foundation.Text |
| import androidx.compose.foundation.background |
| import androidx.compose.foundation.drawBorder |
| import androidx.compose.ui.graphics.Color |
| import androidx.compose.foundation.layout.Column |
| import androidx.compose.foundation.layout.fillMaxSize |
| import androidx.compose.foundation.layout.size |
| import androidx.compose.foundation.layout.wrapContentSize |
| import androidx.ui.unit.IntSize |
| import androidx.ui.unit.TextUnit |
| import androidx.ui.unit.dp |
| |
| /** |
| * Demonstration of how various press/tap gesture interact together in a nested fashion. |
| */ |
| @Composable |
| fun PointerInputDuringSubComp() { |
| Column { |
| Text( |
| "Demonstrates that PointerInputFilters that are currently receiving pointer input " + |
| "events can be removed from the hierarchy by sub composition with no difficulty" |
| ) |
| Text( |
| "Below is an AdapterList with many touchable items. Each item keeps track of the " + |
| "number of pointers touching it. If you touch an item and then scroll so " + |
| "that it goes out of the viewport and then back into the viewport, you will" + |
| " see that it no longer knows that a finger is touching it. That is because " + |
| "it is actually a new item that has not been hit tested yet. If you keep " + |
| "your finger there and then add more fingers, it will track those new fingers." |
| ) |
| LazyColumnItems( |
| List(100) { index -> index }, |
| Modifier |
| .fillMaxSize() |
| .wrapContentSize(Alignment.Center) |
| .size(200.dp) |
| .background(color = Color.White) |
| ) { |
| val pointerCount = state { 0 } |
| |
| Box( |
| Modifier.size(200.dp) |
| .drawBorder(size = 1.dp, color = Color.Black) |
| .pointerCounterGestureFilter { newCount -> pointerCount.value = newCount } |
| ) { |
| Text( |
| "${pointerCount.value}", |
| fontSize = TextUnit.Em(16), |
| color = Color.Black, |
| modifier = Modifier.fillMaxSize().wrapContentSize(Alignment.Center) |
| ) |
| } |
| } |
| } |
| } |
| |
| fun Modifier.pointerCounterGestureFilter( |
| onPointerCountChanged: (Int) -> Unit |
| ): Modifier = |
| composed { |
| val filter = remember { PointerCounterGestureFilter() } |
| filter.onPointerCountChanged = onPointerCountChanged |
| PointerInputModifierImpl(filter) |
| } |
| |
| internal class PointerInputModifierImpl(override val pointerInputFilter: PointerInputFilter) : |
| PointerInputModifier |
| |
| internal class PointerCounterGestureFilter : PointerInputFilter() { |
| |
| lateinit var onPointerCountChanged: (resultingPointerCount: Int) -> Unit |
| |
| override fun onPointerInput( |
| changes: List<PointerInputChange>, |
| pass: PointerEventPass, |
| bounds: IntSize |
| ): List<PointerInputChange> { |
| if (pass == PointerEventPass.PostUp) { |
| if (changes.any { |
| it.changedToDownIgnoreConsumed() || it.changedToUpIgnoreConsumed() |
| }) { |
| onPointerCountChanged.invoke(changes.count { it.current.down }) |
| } |
| } |
| return changes |
| } |
| |
| override fun onCancel() {} |
| } |