AWS Amplify Android构建失败：ModelConfig注解缺失type/version参数问题

我在跟着AWS Android Amplify第5模块「API与数据库」的实现指南操作时，项目构建失败，原因是Amplify自动生成的NoteData.java文件里存在未解析符号。查了ModelConfig.java文件后发现，这个注解并没有定义type和version参数，想请教这两个参数是不是必须的？能不能直接删掉？

自定义ModelConfig注解代码 #

package com.amplifyframework.core.model.annotations;

import com.amplifyframework.core.model.Model;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * {@link ModelConfig} annotates any {@link Model} with applicable configuration information.
 *
 * The {@link RetentionPolicy#RUNTIME} annotation is added to
 * retain {@link ModelConfig} at runtime for the reflection capabilities to work
 * in order to check if this annotation is present for a field of a Model.
 *
 * {@link ElementType#TYPE} annotation is added to indicate
 * {@link ModelConfig} annotation can be used only on types (class, interface, enum).
 */
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
public @interface ModelConfig {
    /**
     * Specifies the plural version of the model name.
     * @return the plural version of the name.
     */
    String pluralName() default "";

    /**
     * Specifies an array of authorization rules that should apply to this {@link Model}.
     * @return list of {@link AuthRule} annotations.
     */
    AuthRule[] authRules() default {};
}

自动生成的NoteData类注解片段 #

import static com.amplifyframework.core.model.query.predicate.QueryField.field;

/** This is an auto generated class representing the NoteData type in your schema. */
@SuppressWarnings("all")
@ModelConfig(pluralName = "NoteData", type = Model.Type.USER, version = 1, authRules = {
  @AuthRule(allow = AuthStrategy.OWNER, ownerField = "owner", identityClaim = "cognito:username", provider = "userPools", operations = { ModelOperation.CREATE, ModelOperation.UPDATE, ModelOperation.DELETE, ModelOperation.READ })
})

解答 #

• type和version参数不是必须的：从你提供的ModelConfig注解定义来看，它只包含pluralName和authRules两个参数，type和version是Amplify后续版本新增的注解参数，但你的本地注解类并没有实现这两个参数，所以编译器会抛出未解析符号的错误。
• 可以直接删除这两个参数：把@ModelConfig里的type = Model.Type.USER, version = 1这段内容删掉，只保留已定义的参数（pluralName和authRules），就能解决构建失败的问题。
• 额外提示：出现这种情况基本是因为你使用的Amplify CLI版本和项目依赖的Amplify SDK版本不匹配。建议检查CLI版本与项目gradle中的Amplify依赖版本，尽量保持一致，避免后续再出现自动生成代码和本地注解不兼容的问题。

内容的提问来源于stack exchange，提问作者nekomaster88