Focusable.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.foundation
import androidx.compose.foundation.interaction.FocusInteraction
import androidx.compose.foundation.interaction.MutableInteractionSource
import androidx.compose.runtime.DisposableEffect
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.rememberCoroutineScope
import androidx.compose.runtime.setValue
import androidx.compose.ui.Modifier
import androidx.compose.ui.composed
import androidx.compose.ui.focus.focusTarget
import androidx.compose.ui.focus.onFocusChanged
import androidx.compose.ui.platform.debugInspectorInfo
import androidx.compose.ui.semantics.focused
import androidx.compose.ui.semantics.semantics
import kotlinx.coroutines.launch
/**
* Configure component to be focusable via focus system or accessibility "focus" event.
*
* Add this modifier to the element to make it focusable within its bounds.
*
* @sample androidx.compose.foundation.samples.FocusableSample
*
* @param enabled Controls the enabled state. When `false`, element won't participate in the focus
* @param interactionSource [MutableInteractionSource] that will be used to emit
* [FocusInteraction.Focus] when this element is being focused.
*/
fun Modifier.focusable(
enabled: Boolean = true,
interactionSource: MutableInteractionSource? = null,
) = composed(
inspectorInfo = debugInspectorInfo {
name = "focusable"
properties["enabled"] = enabled
properties["interactionSource"] = interactionSource
}
) {
val scope = rememberCoroutineScope()
val focusedInteraction = remember { mutableStateOf<FocusInteraction.Focus?>(null) }
var isFocused by remember { mutableStateOf(false) }
DisposableEffect(interactionSource) {
onDispose {
focusedInteraction.value?.let { oldValue ->
val interaction = FocusInteraction.Unfocus(oldValue)
interactionSource?.tryEmit(interaction)
focusedInteraction.value = null
}
}
}
DisposableEffect(enabled) {
if (!enabled) {
scope.launch {
focusedInteraction.value?.let { oldValue ->
val interaction = FocusInteraction.Unfocus(oldValue)
interactionSource?.emit(interaction)
focusedInteraction.value = null
}
}
}
onDispose { }
}
if (enabled) {
Modifier
.semantics {
this.focused = isFocused
}
.onFocusChanged {
isFocused = it.isFocused
if (isFocused) {
scope.launch {
focusedInteraction.value?.let { oldValue ->
val interaction = FocusInteraction.Unfocus(oldValue)
interactionSource?.emit(interaction)
focusedInteraction.value = null
}
val interaction = FocusInteraction.Focus()
interactionSource?.emit(interaction)
focusedInteraction.value = interaction
}
} else {
scope.launch {
focusedInteraction.value?.let { oldValue ->
val interaction = FocusInteraction.Unfocus(oldValue)
interactionSource?.emit(interaction)
focusedInteraction.value = null
}
}
}
}
.focusTarget()
} else {
Modifier
}
}