commonMain.androidx.compose.ui.input.key.KeyInputModifierNode.kt Maven / Gradle / Ivy

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Compose UI primitives. This library contains the primitives that form the Compose UI Toolkit, such as drawing, measurement and layout.

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/*
 * Copyright 2023 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.Modifier
import androidx.compose.ui.node.DelegatableNode

/**
 * 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.
 */
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
}