I would like to use safeargs in Android for navigation. Unfortunately I always get an error from the grandle files telling "Could not get unknown property 'nav_version' for object of type org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler".

Actually I think the problem might be because of mixing Java and Kotlin? There were some kotlin files that I converted into Java but I received this error message when inserting the arguments for the safeargs in the build.gradle file. So actually I don't need any Kotlin related stuff anymore in the build.grandl files and I tried to remove them but then I receivede the same error messages. Do you know how I can solve this problem?

Here are my build.gradle files:

// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
    ext.kotlin_version = "1.4.10"
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath "com.android.tools.build:gradle:4.1.1"
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        classpath "androidx.navigation:navigation-safe-args-gradle-plugin:$nav_version"

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

Here the second one:

plugins {
    id 'com.android.application'
    id 'kotlin-android'
}


apply plugin: "androidx.navigation.safeargs"

android {
    compileSdkVersion 30
    buildToolsVersion "30.0.3"

    defaultConfig {
        applicationId "com.nikhiljain.canvasdrawingsample"
        minSdkVersion 21
        targetSdkVersion 30
        versionCode 1
        versionName "1.0"
        viewBinding {
            enabled = true
        }

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = '1.8'
    }
}

dependencies {

    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
    implementation 'androidx.core:core-ktx:1.3.2'
    implementation 'androidx.appcompat:appcompat:1.2.0'
    implementation 'com.google.android.material:material:1.3.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
    implementation 'androidx.navigation:navigation-fragment-ktx:2.3.5'
    implementation 'androidx.navigation:navigation-ui-ktx:2.3.5'
    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
    testImplementation 'junit:junit:4. '
    androidTestImplementation 'androidx.test.ext:junit:1.1.2'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
    implementation "androidx.navigation:navigation-fragment:$nav_version"
    implementation "androidx.navigation:navigation-ui:$nav_version"
}

CodePudding user response：

I think you need to add this just below this line ext.kotlin_version = "1.4.10"

ext.nav_version = "2.3.5"

where 2.3.5 is the desired version , but am not pretty sure about this .

and am not sure that you posted the whole gradle file , but you missing this with the part you posted .

the same way you used ext.kotlin_version = "1.4.10" and then in dependency section you called

classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"

its totally equal too

classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.4.10"

You can also do it like this

buildscript {
    repositories {
        google()
    }
    dependencies {
        val nav_version = "2.3.5"
        classpath("androidx.navigation:navigation-safe-args-gradle-plugin:$nav_version")
    }
}

or just remove all the $kotlin_version in your build.gradle and replace with 2.3.5 for example .