Android Studio更新后无法解析符号"NonNull" [英] Cannot resolve symbol 'NonNull' after Android Studio update

问题描述

我最近更新了Android Studio.之后，似乎不再能够解析某些支持注释，例如@NonNull或@Nullable.在更新之前，它确实工作正常.但是，所有内容仍在编译中，并且我能够执行Code，但仍然显示在导入时符号无法解析的消息.

I recently updated Android Studio. Afterwards it seems to no longer being able to resolve some support annotations, such as @NonNull or @Nullable. It did work just fine before updating. However, everything is still compiling and I am able to execute Code, but still it shows the symbol cannot be resolved message at my imports.

到目前为止我已经尝试过的:

What I have already tried so far:

1. 在build.gradle中包含了依赖项(模块:应用程序):

1. Included the dependency in build.gradle (Module: Application):

compile 'com.android.support:support-annotations:27.0.0'

我已使缓存无效并重新启动

清洁和重建项目

(编辑)同步Gradle

我不知道为什么这不起作用，非常感谢您的帮助.

I have no idea why this is not working and would really appreciate your help.

推荐答案

从android api 29('targetSdkVersion'29)开始，com.android.support已移至"androidx"库.

As of android api 29 ('targetSdkVersion' 29) com.android.support has been moved to 'androidx' library.

在您的build.gradle文件(应用级别)中，依赖项被阻止使用...

In your build.gradle file(app level), dependencies block use...

dependencies{ 
    ...
    implementation 'androidx.annotation:annotation:1.1.0' 
}

在您的.java文件中，使用import，如下所示:

And in your .java files use import as follows:

import androidx.annotation.NonNull;

再次构建您的项目！

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