ZIndexModifier.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.Stable
import androidx.compose.ui.platform.InspectableParameter
import androidx.compose.ui.platform.ParameterElement
/**
* A [Modifier.Element] that controls the drawing order for the children of the same layout
* parent. A child with larger [zIndex] will be drawn after all the children with smaller [zIndex].
* When children have the same [zIndex] the original order in which the items were added into the
* parent layout is applied.
* Note that if there would be multiple [ZIndexModifier] modifiers applied for the same layout
* only the first one in the modifiers chain will be used. If no [ZIndexModifier]s applied for the
* layout then zIndex for this Layout is 0.
*
* @see [Modifier.zIndex]
*/
interface ZIndexModifier : Modifier.Element {
val zIndex: Float
}
/**
* Creates a [ZIndexModifier] that controls the drawing order for the children of the same layout
* parent. A child with larger [zIndex] will be drawn after all the children with smaller [zIndex].
* When children have the same [zIndex] the original order in which the items were added into the
* parent layout is applied.
* Note that if there would be multiple [ZIndexModifier] modifiers applied for the same layout
* only the first one in the modifiers chain will be used. If no [ZIndexModifier]s applied for the
* layout then zIndex for this Layout is 0.
*
* @sample androidx.compose.ui.samples.ZIndexModifierSample
*/
@Stable
fun Modifier.zIndex(zIndex: Float): Modifier = this.then(SimpleZIndexModifier(zIndex))
private data class SimpleZIndexModifier(override val zIndex: Float) : ZIndexModifier,
InspectableParameter {
override val nameFallback = "zIndex"
override val valueOverride = zIndex
override val inspectableElements = emptySequence<ParameterElement>()
}