FocusModifier.kt
/*
* 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
import androidx.compose.runtime.Composable
import androidx.compose.runtime.remember
import androidx.compose.ui.focus.ExperimentalFocus
import androidx.compose.ui.focus.FocusState
import androidx.compose.ui.node.ModifiedFocusNode
/**
* A [Modifier.Element] that wraps makes the modifiers on the right into a Focusable. Use a
* different instance of [FocusModifier] for each focusable component.
*/
@OptIn(ExperimentalFocus::class)
internal class FocusModifier(
initialFocus: FocusState
) : Modifier.Element {
var focusState: FocusState = initialFocus
set(value) {
field = value
focusNode.wrappedBy?.propagateFocusStateChange(value)
}
var focusedChild: ModifiedFocusNode? = null
lateinit var focusNode: ModifiedFocusNode
}
/**
* Add this modifier to a component to make it focusable.
*/
@ExperimentalFocus
@Composable
fun Modifier.focus(): Modifier = this.then(remember { FocusModifier(FocusState.Inactive) })