1 /*
2  * Copyright 2025 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package androidx.compose.ui.input.indirect
18 
19 import androidx.compose.ui.ExperimentalComposeUiApi
20 import androidx.compose.ui.Modifier
21 import androidx.compose.ui.node.DelegatableNode
22 
23 /**
24  * Implement this interface to create a [Modifier.Node] that can intercept indirect touch input
25  * events.
26  *
27  * The event is routed to the focused item. Before reaching the focused item,
28  * [onPreIndirectTouchEvent] is called for parents of the focused item. If the parents don't consume
29  * the event, [onPreIndirectTouchEvent] is called for the focused item. If the event is still not
30  * consumed, [onIndirectTouchEvent] is called on the focused item's parents.
31  */
32 @ExperimentalComposeUiApi
33 interface IndirectTouchInputModifierNode : DelegatableNode {
34 
35     /**
36      * This function is called when an [IndirectTouchEvent] is received by this node during the
37      * upward pass. While implementing this callback, return true to stop propagation of this event.
38      * If you return false, the generic motion event will be sent to this
39      * [IndirectTouchInputModifierNode]'s parent.
40      */
onIndirectTouchEventnull41     fun onIndirectTouchEvent(event: IndirectTouchEvent): Boolean
42 
43     /**
44      * This function is called when an [IndirectTouchEvent] is received by this node during the
45      * downward pass. It gives ancestors of a focused component the chance to intercept an event.
46      * Return true to stop propagation of this event. If you return false, the event will be sent to
47      * this [IndirectTouchInputModifierNode]'s child. If none of the children consume the event, it
48      * will be sent back up to the root using the [onIndirectTouchEvent] function.
49      */
50     fun onPreIndirectTouchEvent(event: IndirectTouchEvent): Boolean
51 }
52