/*
* 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.Modifier
import androidx.compose.ui.focus.FocusModifier
import androidx.compose.ui.focus.ModifierLocalParentFocusModifier
import androidx.compose.ui.focus.findActiveFocusNode
import androidx.compose.ui.focus.findLastKeyInputModifier
import androidx.compose.ui.layout.LayoutCoordinates
import androidx.compose.ui.layout.OnPlacedModifier
import androidx.compose.ui.modifier.ModifierLocalConsumer
import androidx.compose.ui.modifier.ModifierLocalProvider
import androidx.compose.ui.modifier.ModifierLocalReadScope
import androidx.compose.ui.modifier.ProvidableModifierLocal
import androidx.compose.ui.modifier.modifierLocalOf
import androidx.compose.ui.node.LayoutNode
import androidx.compose.ui.node.LayoutNodeWrapper
import androidx.compose.ui.platform.debugInspectorInfo
import androidx.compose.ui.platform.inspectable
/**
* 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
*/
fun Modifier.onKeyEvent(onKeyEvent: (KeyEvent) -> Boolean): Modifier = inspectable(
inspectorInfo = debugInspectorInfo {
name = "onKeyEvent"
properties["onKeyEvent"] = onKeyEvent
}
) {
KeyInputModifier(onKeyEvent = onKeyEvent, onPreviewKeyEvent = null)
}
/**
* 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 [KeyInputModifier] using the onKeyEvent callback.
*
* @sample androidx.compose.ui.samples.KeyEventSample
*/
fun Modifier.onPreviewKeyEvent(onPreviewKeyEvent: (KeyEvent) -> Boolean): Modifier = inspectable(
inspectorInfo = debugInspectorInfo {
name = "onPreviewKeyEvent"
properties["onPreviewKeyEvent"] = onPreviewKeyEvent
}
) {
KeyInputModifier(onKeyEvent = null, onPreviewKeyEvent = onPreviewKeyEvent)
}
/**
* Used to build a tree of [KeyInputModifier]s. This contains the [KeyInputModifier] that is
* higher in the layout tree.
*/
internal val ModifierLocalKeyInput = modifierLocalOf<KeyInputModifier?> { null }
internal class KeyInputModifier(
val onKeyEvent: ((KeyEvent) -> Boolean)?,
val onPreviewKeyEvent: ((KeyEvent) -> Boolean)?
) : ModifierLocalConsumer, ModifierLocalProvider<KeyInputModifier?>, OnPlacedModifier {
private var focusModifier: FocusModifier? = null
var parent: KeyInputModifier? = null
private set
var layoutNode: LayoutNode? = null
private set
override val key: ProvidableModifierLocal<KeyInputModifier?>
get() = ModifierLocalKeyInput
override val value: KeyInputModifier
get() = this
fun processKeyInput(keyEvent: KeyEvent): Boolean {
val activeKeyInputModifier = focusModifier
?.findActiveFocusNode()
?.findLastKeyInputModifier()
?: error("KeyEvent can't be processed because this key input node is not active.")
val consumed = activeKeyInputModifier.propagatePreviewKeyEvent(keyEvent)
return if (consumed) true else activeKeyInputModifier.propagateKeyEvent(keyEvent)
}
override fun onModifierLocalsUpdated(scope: ModifierLocalReadScope) = with(scope) {
focusModifier?.keyInputChildren?.remove(this@KeyInputModifier)
focusModifier = ModifierLocalParentFocusModifier.current
focusModifier?.keyInputChildren?.add(this@KeyInputModifier)
parent = ModifierLocalKeyInput.current
}
fun propagatePreviewKeyEvent(keyEvent: KeyEvent): Boolean {
// We first propagate the preview key event to the parent.
val consumed = parent?.propagatePreviewKeyEvent(keyEvent)
if (consumed == true) return consumed
// If none of the parents consumed the event, we attempt to consume it.
return onPreviewKeyEvent?.invoke(keyEvent) ?: false
}
fun propagateKeyEvent(keyEvent: KeyEvent): Boolean {
// We attempt to consume the key event first.
val consumed = onKeyEvent?.invoke(keyEvent)
if (consumed == true) return consumed
// If the event is not consumed, we propagate it to the parent.
return parent?.propagateKeyEvent(keyEvent) ?: false
}
override fun onPlaced(coordinates: LayoutCoordinates) {
layoutNode = (coordinates as LayoutNodeWrapper).layoutNode
}
}