/*
* 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.compose.ui.input.key
import androidx.compose.ui.ExperimentalComposeUiApi
import androidx.compose.ui.Modifier
import androidx.compose.ui.node.DelegatableNode
import androidx.compose.ui.node.modifierElementOf
/**
* Implement this interface to create a [Modifier.Node] that can intercept hardware Key events.
*
* The event is routed to the focused item. Before reaching the focused item, [onPreKeyEvent]() is
* called for parents of the focused item. If the parents don't consume the event, [onPreKeyEvent]()
* is called for the focused item. If the event is still not consumed, [onKeyEvent]() is called on
* the focused item's parents.
*/
@ExperimentalComposeUiApi
interface KeyInputModifierNode : DelegatableNode {
/**
* This function is called when a [KeyEvent] is received by this node during the upward
* pass. While implementing this callback, return true to stop propagation of this event. If you
* return false, the key event will be sent to this [KeyInputModifierNode]'s parent.
*/
fun onKeyEvent(event: KeyEvent): Boolean
/**
* This function is called when a [KeyEvent] is received by this node during the
* downward pass. It gives ancestors of a focused component the chance to intercept an event.
* Return true to stop propagation of this event. If you return false, the event will be sent
* to this [KeyInputModifierNode]'s child. If none of the children consume the event,
* it will be sent back up to the root using the [onKeyEvent] function.
*/
fun onPreKeyEvent(event: KeyEvent): Boolean
}
@ExperimentalComposeUiApi
internal class KeyInputInputModifierNodeImpl(
var onEvent: ((KeyEvent) -> Boolean)?,
var onPreEvent: ((KeyEvent) -> Boolean)?
) : KeyInputModifierNode, Modifier.Node() {
override fun onKeyEvent(event: KeyEvent): Boolean = this.onEvent?.invoke(event) ?: false
override fun onPreKeyEvent(event: KeyEvent): Boolean = this.onPreEvent?.invoke(event) ?: false
}
/**
* Adding this [modifier][Modifier] to the [modifier][Modifier] parameter of a component will
* allow it to intercept hardware key events when it (or one of its children) is focused.
*
* @param onKeyEvent This callback is invoked when the user interacts with the hardware keyboard.
* While implementing this callback, return true to stop propagation of this event. If you return
* false, the key event will be sent to this [onKeyEvent]'s parent.
*
* @sample androidx.compose.ui.samples.KeyEventSample
*/
@OptIn(ExperimentalComposeUiApi::class)
@Suppress("ModifierInspectorInfo") // b/251831790.
fun Modifier.onKeyEvent(onKeyEvent: (KeyEvent) -> Boolean): Modifier = this.then(
modifierElementOf(
key = onKeyEvent,
create = { KeyInputInputModifierNodeImpl(onEvent = onKeyEvent, onPreEvent = null) },
update = { it.onEvent = onKeyEvent },
definitions = {
name = "onKeyEvent"
properties["onKeyEvent"] = onKeyEvent
}
)
)
/**
* Adding this [modifier][Modifier] to the [modifier][Modifier] parameter of a component will
* allow it to intercept hardware key events when it (or one of its children) is focused.
*
* @param onPreviewKeyEvent This callback is invoked when the user interacts with the hardware
* keyboard. It gives ancestors of a focused component the chance to intercept a [KeyEvent].
* Return true to stop propagation of this event. If you return false, the key event will be sent
* to this [onPreviewKeyEvent]'s child. If none of the children consume the event, it will be
* sent back up to the root [KeyInputModifierNode] using the onKeyEvent callback.
*
* @sample androidx.compose.ui.samples.KeyEventSample
*/
@OptIn(ExperimentalComposeUiApi::class)
@Suppress("ModifierInspectorInfo") // b/251831790.
fun Modifier.onPreviewKeyEvent(onPreviewKeyEvent: (KeyEvent) -> Boolean): Modifier = this.then(
modifierElementOf(
key = onPreviewKeyEvent,
create = { KeyInputInputModifierNodeImpl(onEvent = null, onPreEvent = onPreviewKeyEvent) },
update = { it.onPreEvent = onPreviewKeyEvent },
definitions = {
name = "onPreviewKeyEvent"
properties["onPreviewKeyEvent"] = onPreviewKeyEvent
}
)
)