1 /*
2  * Copyright 2023 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.rotary
18 
19 import androidx.compose.ui.Modifier
20 import androidx.compose.ui.node.DelegatableNode
21 
22 /**
23  * Implement this interface to create a [Modifier.Node] that can intercept rotary scroll events.
24  *
25  * The event is routed to the focused item. Before reaching the focused item,
26  * [onPreRotaryScrollEvent]() is called for parents of the focused item. If the parents don't
27  * consume the event, [onPreRotaryScrollEvent]() is called for the focused item. If the event is
28  * still not consumed, [onRotaryScrollEvent]() is called on the focused item's parents.
29  */
30 interface RotaryInputModifierNode : DelegatableNode {
31     /**
32      * This function is called when a [RotaryScrollEvent] is received by this node during the upward
33      * pass. While implementing this callback, return true to stop propagation of this event. If you
34      * return false, the key event will be sent to this [RotaryInputModifierNode]'s parent.
35      */
onRotaryScrollEventnull36     fun onRotaryScrollEvent(event: RotaryScrollEvent): Boolean
37 
38     /**
39      * This function is called when a [RotaryScrollEvent] is received by this node during the
40      * downward pass. It gives ancestors of a focused component the chance to intercept an event.
41      * Return true to stop propagation of this event. If you return false, the event will be sent to
42      * this [RotaryInputModifierNode]'s child. If none of the children consume the event, it will be
43      * sent back up to the root using the [onRotaryScrollEvent] function.
44      */
45     fun onPreRotaryScrollEvent(event: RotaryScrollEvent): Boolean
46 }
47