ModifiedFocusEventNode.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.node
import androidx.compose.ui.focus.FocusEventModifier
import androidx.compose.ui.focus.FocusState
import androidx.compose.ui.focus.FocusStateImpl.Inactive
import androidx.compose.ui.focus.searchChildrenForFocusNode
internal class ModifiedFocusEventNode(
wrapped: LayoutNodeWrapper,
modifier: FocusEventModifier
) : DelegatingLayoutNodeWrapper<FocusEventModifier>(wrapped, modifier) {
override fun propagateFocusEvent(focusState: FocusState) {
modifier.onFocusEvent(focusState)
super.propagateFocusEvent(focusState)
}
override fun onModifierChanged() {
super.onModifierChanged()
// If the modifier is re-used, we can't be sure that it is in the same position as before.
// For instance, if the observer is moved to the end of the list, and there is no focus
// modifier following this observer, it's focus state will be invalid. To solve this, we
// always reset the focus state when a focus observer is re-used.
val focusNode = wrapped.findNextFocusWrapper() ?: layoutNode.searchChildrenForFocusNode()
modifier.onFocusEvent(focusNode?.modifier?.focusState ?: Inactive)
}
}