| /* |
| * 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 |
| |
| import androidx.compose.Composable |
| |
| /** |
| * [PointerInput] is the compose ui core component for receiving and interacting with pointer input. |
| * |
| * Pointer input includes all user input related to 2d positioning on the screen. This includes |
| * (but is not necessarily limited to) fingers touching the screen, a mouse moving across the |
| * screen, and stylus input. |
| * |
| * [PointerInput] takes the virtual size of all of it's descendant [Layout] nodes and when a pointer |
| * comes in contact with the screen, hit testing is automatically done using that virtual size. |
| * |
| * [pointerInputHandler] is invoked when pointers that have hit tested positive change. |
| * |
| * [cancelHandler] is invoked to notify the handler that no more calls to pointerInputHandler will |
| * be made, until at least new pointers exist. This can occur for a few reasons: |
| * 1. Android dispatches ACTION_CANCEL to [AndroidComposeView.onTouchEvent]. |
| * 2. The PointerInputNode has been removed from the compose hierarchy. |
| * 3. The PointerInputNode no longer has any descendant [LayoutNode]s and therefore does not |
| * know what region of the screen it should virtually exist in. |
| * |
| * @param pointerInputHandler Invoked when pointers that have hit this [PointerInput] change. |
| * @param cancelHandler Invoked when a cancellation event occurs. |
| * @param children The children composable that will be composed as a child, or children, of this |
| * [PointerInput]. |
| */ |
| @Composable |
| inline fun PointerInput( |
| noinline pointerInputHandler: PointerInputHandler, |
| noinline cancelHandler: () -> Unit, |
| crossinline children: @Composable() () -> Unit |
| ) { |
| // Hide the internals of PointerInputNode |
| PointerInputNode(pointerInputHandler = pointerInputHandler, cancelHandler = cancelHandler) { |
| children() |
| } |
| } |