commonMain.androidx.compose.foundation.lazy.LazyItemScope.kt Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of foundation-desktop Show documentation
Higher level abstractions of the Compose UI primitives. This library is design system agnostic, providing the high-level building blocks for both application and design-system developers
The newest version!
/*
 * 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.lazy

import androidx.annotation.FloatRange
import androidx.compose.animation.core.FiniteAnimationSpec
import androidx.compose.animation.core.Spring
import androidx.compose.animation.core.VisibilityThreshold
import androidx.compose.animation.core.spring
import androidx.compose.foundation.internal.JvmDefaultWithCompatibility
import androidx.compose.runtime.Stable
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.Constraints
import androidx.compose.ui.unit.IntOffset

/** Receiver scope being used by the item content parameter of LazyColumn/Row. */
@Stable
@LazyScopeMarker
@JvmDefaultWithCompatibility
interface LazyItemScope {
    /**
     * Have the content fill the [Constraints.maxWidth] and [Constraints.maxHeight] of the parent
     * measurement constraints by setting the [minimum width][Constraints.minWidth] to be equal to
     * the [maximum width][Constraints.maxWidth] multiplied by [fraction] and the
     * [minimum height][Constraints.minHeight] to be equal to the
     * [maximum height][Constraints.maxHeight] multiplied by [fraction]. Note that, by default, the
     * [fraction] is 1, so the modifier will make the content fill the whole available space.
     * [fraction] must be between `0` and `1`.
     *
     * Regular [Modifier.fillMaxSize] can't work inside the scrolling layouts as the items are
     * measured with [Constraints.Infinity] as the constraints for the main axis.
     */
    fun Modifier.fillParentMaxSize(@FloatRange(from = 0.0, to = 1.0) fraction: Float = 1f): Modifier

    /**
     * Have the content fill the [Constraints.maxWidth] of the parent measurement constraints by
     * setting the [minimum width][Constraints.minWidth] to be equal to the
     * [maximum width][Constraints.maxWidth] multiplied by [fraction]. Note that, by default, the
     * [fraction] is 1, so the modifier will make the content fill the whole parent width.
     * [fraction] must be between `0` and `1`.
     *
     * Regular [Modifier.fillMaxWidth] can't work inside the scrolling horizontally layouts as the
     * items are measured with [Constraints.Infinity] as the constraints for the main axis.
     */
    fun Modifier.fillParentMaxWidth(
        @FloatRange(from = 0.0, to = 1.0) fraction: Float = 1f
    ): Modifier

    /**
     * Have the content fill the [Constraints.maxHeight] of the incoming measurement constraints by
     * setting the [minimum height][Constraints.minHeight] to be equal to the
     * [maximum height][Constraints.maxHeight] multiplied by [fraction]. Note that, by default, the
     * [fraction] is 1, so the modifier will make the content fill the whole parent height.
     * [fraction] must be between `0` and `1`.
     *
     * Regular [Modifier.fillMaxHeight] can't work inside the scrolling vertically layouts as the
     * items are measured with [Constraints.Infinity] as the constraints for the main axis.
     */
    fun Modifier.fillParentMaxHeight(
        @FloatRange(from = 0.0, to = 1.0) fraction: Float = 1f
    ): Modifier

    /**
     * This modifier animates the item appearance (fade in), disappearance (fade out) and placement
     * changes (such as an item reordering).
     *
     * You should also provide a key via [LazyListScope.item]/[LazyListScope.items] for this
     * modifier to enable animations.
     *
     * @sample androidx.compose.foundation.samples.AnimateItemSample
     * @param fadeInSpec an animation specs to use for animating the item appearance. When null is
     *   provided the item will be appearing without animations.
     * @param placementSpec an animation specs that will be used to animate the item placement.
     *   Aside from item reordering all other position changes caused by events like arrangement or
     *   alignment changes will also be animated. When null is provided no animations will happen.
     * @param fadeOutSpec an animation specs to use for animating the item disappearance. When null
     *   is provided the item will be disappearance without animations.
     */
    fun Modifier.animateItem(
        fadeInSpec: FiniteAnimationSpec? = spring(stiffness = Spring.StiffnessMediumLow),
        placementSpec: FiniteAnimationSpec? =
            spring(
                stiffness = Spring.StiffnessMediumLow,
                visibilityThreshold = IntOffset.VisibilityThreshold
            ),
        fadeOutSpec: FiniteAnimationSpec? = spring(stiffness = Spring.StiffnessMediumLow),
    ): Modifier = this
}