com.facebook.litho.annotations.LayoutSpec Maven / Gradle / Ivy
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/*
* Copyright (c) Meta Platforms, Inc. and affiliates.
*
* 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 com.facebook.litho.annotations;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
/**
* A class that is annotated with this annotation will be used to create a composite component that
* is made up of other components. A layout spec is the logical equivalent of a composite view in
* Android.
*
* The class annotated with {@link LayoutSpec} must implement a method with the {@link
* OnCreateLayout} or {@link OnCreateLayoutWithSizeSpec} annotation. It may also implement methods
* with the following annotations:
*
*
* - {@link OnCreateInitialState}
*
- {@link OnCreateTreeProp}
*
- {@link OnCreateTransition}
*
- {@link OnUpdateState}
*
- {@link OnEvent}
*
- {@link OnLoadStyle}
*
- {@link OnEnteredRange}
*
- {@link OnExitedRange}
*
- {@link OnRegisterRanges}
*
- {@link OnCalculateCachedValue}
*
- {@link ShouldUpdate}
*
*
* Example:
*
*
{@literal @LayoutSpec}
* public class CounterSpec {
*
* {@literal @OnCreateLayout}
* static Component onCreateLayout(
* ComponentContext c,
* {@literal @Prop} int id,
* {@literal @State} int count) {
*
* return Row.create(c)
* .backgroundColor(Color.WHITE)
* .heightDip(64)
* .paddingDip(YogaEdge.ALL, 8)
* .child(
* Text.create(c)
* .text(" + ")
* .clickHandler(Counter.onClick(c))
* )
* .child(
* Text.create(c)
* .text(String.valueOf(count))
* )
* .build();
* }
*
* {@literal @OnCreateInitialState}
* static void onCreateInitialState(
* ComponentContext c,
* StateValue<Integer> count) {
* count.set(0);
* }
*
* {@literal @OnEvent(ClickEvent.class)}
* static void onClick(ComponentContext c, @Prop int id) {
* Counter.increment(c, id);
* }
*
* {@literal @OnUpdateState}
* static void increment(StateValue<Integer> count, @Param int counterId) {
* count.set(count.get() + 1);
* }
* }
*
* 
*
* If you want to create a component that mounts its own content, then use {@link MountSpec}
* instead. See more docs at https://fblitho.com
*
* @see Prop
* @see TreeProp
* @see InjectProp
* @see State
* @see Param
* @deprecated Use {@link com.facebook.litho.KComponent}s for new derived components instead of
* {@code LayoutSpec}s. Specs should only be used in Java.
*
*
If you're new to Kotlin API, read
* Migrating to the Kotlin API docs.
*
If you're familiar with it, you can go straight to the APIs matching
* cheatsheet.
*/
@Deprecated
@Retention(RetentionPolicy.RUNTIME)
public @interface LayoutSpec {
/**
* Class name of the generated component. When not provided defaults to name of the annotated
* class sans the "Spec" suffix. E.g. "MyComponentSpec" to "MyComponent".
*
*
In order to avoid confusion, this should only be used if you have a very good reason for it.
* For instance to avoid naming collisions.
*/
String value() default "";
/**
* @return Boolean indicating whether the generated class should be public. If not, it will be
* package-private.
*/
boolean isPublic() default true;
/**
* @return List of event POJOs this component can dispatch. Used to generate event dispatch
* methods.
*/
Class[] events() default {};
/**
* @return List of trigger POJOs this component can dispatch. Used to generate trigger creation
* methods.
*/
Class[] triggers() default {};
/**
* @return the prop name of the Component this component will delegate getSimpleName calls to.
* This will cause getSimpleName to include the name of that component in its return. This is
* useful for seeing better debug information when using generic wrapping components (like
* error boundary wrappers).
*/
String simpleNameDelegate() default "";
}