react native - error: package com.android.annotations does not exist

Question

I have the following class

import com.android.annotations.NonNullByDefault;

@NonNullByDefault
public final class Log {
    ...
}

and here is my build.gradle file (some parts omitted)

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
    buildToolsVersion '24.0.1'

    defaultConfig {
        minSdkVersion 16
        targetSdkVersion 25
        versionCode 2
        versionName "0.2"
    }

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_7
        targetCompatibility JavaVersion.VERSION_1_7
    }

}

dependencies {    
    compile 'com.android.support:appcompat-v7:25.0.0'
    compile 'com.android.support:support-annotations:25.0.0'
    compile 'com.android.support:design:25.0.0'
}

In Android Studio there is no warning raised for my class

However when I try to build and run my app I get this error from gradle

Information:Gradle tasks [:app:clean, :app:generateDebugSources, :app:generateDebugAndroidTestSources, :app:mockableAndroidJar, :app:prepareDebugUnitTestDependencies, :app:assembleDebug]
Warning:[options] bootstrap class path not set in conjunction with -source 1.7
/home/puter/git-repos/TaskManager3/app/src/main/java/com/treemetrics/taskmanager3/util/Log.java
Error:(3, 31) error: package com.android.annotations does not exist
Error:(7, 2) error: cannot find symbol class NonNullByDefault
Error:Execution failed for task ':app:compileDebugJavaWithJavac'.
> Compilation failed; see the compiler error output for details.
Information:BUILD FAILED
Information:Total time: 21.021 secs
Information:3 errors
Information:1 warning
Information:See complete output in console

Answer 1

To automatically fix all android to androidx issues for React Native (prerequisite npx)

Add the following two flags to true in your gradle.properties file at ProjectFolder/android/gradle.properties

android.useAndroidX=true
android.enableJetifier=true

Execute

npm install --save-dev jetifier
npx jetify
npx react-native run-android

In your package.json add the following to scripts

  "postinstall" : "npx jetify"

More info at https://github.com/mikehardy/jetifier

Update: This is now in-built in react-native 0.60. If you migrate to react-native 0.60 you won't need this step. - https://facebook.github.io/react-native/blog/2019/07/03/version-60#androidx-support