| /* |
| * Copyright 2019 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.ui.core |
| |
| import androidx.compose.Immutable |
| import androidx.compose.Stable |
| import androidx.ui.unit.Density |
| |
| /** |
| * Tag the element with [id] to identify the element within its parent. |
| * |
| * Example usage: |
| * @sample androidx.ui.core.samples.LayoutTagChildrenUsage |
| */ |
| @Stable |
| fun Modifier.layoutId(id: Any) = this + LayoutId(id) |
| |
| /** |
| * Tag the element with [tag] to identify the element within its parent. |
| */ |
| @Stable |
| @Deprecated( |
| "tag has been deprecated, layoutId should be used instead.", |
| ReplaceWith("layoutId(tag)", "androidx.ui.core.layoutId") |
| ) |
| fun Modifier.tag(tag: Any) = this + LayoutId(tag) |
| |
| /** |
| * A [ParentDataModifier] which tags the target with the given [id]. The provided tag |
| * will act as parent data, and can be used for example by parent layouts to associate |
| * composable children to [Measurable]s when doing layout, as shown below. |
| */ |
| @Immutable |
| private data class LayoutId(override val id: Any) : ParentDataModifier, LayoutIdParentData { |
| override fun Density.modifyParentData(parentData: Any?): Any? { |
| return this@LayoutId |
| } |
| } |
| |
| /** |
| * Can be implemented by values used as parent data to make them usable as tags. |
| * If a parent data value implements this interface, it can then be returned when querying |
| * [Measurable.id] for the corresponding child. |
| */ |
| interface LayoutIdParentData { |
| val id: Any |
| } |
| |
| @Deprecated( |
| "LayoutTagParentData is deprecated, use LayoutIdParentData instead.", |
| ReplaceWith("LayoutIdParentData", "androidx.ui.core.LayoutIdParentData") |
| ) |
| interface LayoutTagParentData { |
| val tag: Any |
| } |
| |
| /** |
| * Retrieves the tag associated to a composable with the [Modifier.layoutId] modifier. |
| * For a parent data value to be returned by this property when not using the [Modifier.layoutId] |
| * modifier, the parent data value should implement the [LayoutIdParentData] interface. |
| * |
| * Example usage: |
| * @sample androidx.ui.core.samples.LayoutTagChildrenUsage |
| */ |
| val Measurable.id: Any? |
| get() = (parentData as? LayoutIdParentData)?.id |
| |
| @Deprecated( |
| "tag is deprecated, use id instead.", |
| ReplaceWith("id", "androidx.ui.core.id") |
| ) |
| val Measurable.tag: Any? |
| get() = (parentData as? LayoutIdParentData)?.id |