Cause: androidx.navigation.safeargs can only be used with an androidx project

I am facing issue with navigation component called safeargs.

I have used classpath 'androidx.navigation:navigation-safe-args-gradle-plugin:2.0.0' in build gradle.

While applying plugin androidx.navigation.safeargs.kotlin in app/build.gradle, I am getting following error:

Cause: androidx.navigation.safeargs can only be used with an androidx project

app/build.gradle

apply plugin: 'com.android.application'

apply plugin: 'kotlin-android'

apply plugin: 'kotlin-android-extensions'

apply plugin: 'androidx.navigation.safeargs.kotlin'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.test.navigationexample"
        minSdkVersion 14
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation"org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'androidx.appcompat:appcompat:1.1.0-alpha04'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.0-alpha4'
    implementation 'com.google.android.material:material:1.1.0-alpha05'
    implementation 'androidx.navigation:navigation-fragment-ktx:2.0.0'
    implementation 'androidx.navigation:navigation-ui-ktx:2.0.0'
}

As per the Migrate to AndroidX, your gradle.properties file must contain the following lines:

android.useAndroidX=true
android.enableJetifier=true

That first line, android.useAndroidX=true, is what the androidx.navigation.safeargs.kotlin uses to ensure you are using an AndroidX project (it is also used by other tools in Android Studio to generate the right classes, such as when you are using any of the templates).

One other thing to remember is that apply plugin:"androidx.navigation.safeargs.kotlin" shouldn't be the top most apply on build.gradle.

This doesn't work:

apply plugin: 'androidx.navigation.safeargs.kotlin'
apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
apply plugin: 'kotlin-kapt'

This works:

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
apply plugin: 'kotlin-kapt'
apply plugin: 'androidx.navigation.safeargs.kotlin'

Put classpath "androidx.navigation:navigation-safe-args-gradle-plugin:2.3.0" to your project build.gradle in buildscript.dependencies section.

But put apply plugin: 'androidx.navigation.safeargs' to your app build.gradle.

I think there is a bug. If your problem continues, you can try it like this. It worked for me too.

id 'com.android.application'
id 'kotlin-android'
id 'kotlin-android-extensions'
id 'androidx.navigation.safeargs.kotlin'

If you have added the below lines in Gradle properties file then its okay

android.useAndroidX=true
android.enableJetifier=true

Please add this line to your project-level build.gradle

classpath "androidx.navigation:navigation-safe-args-gradle-plugin:2.3.5"

or current updated version.