Safe Args

The recommended way to navigate between destinations is to use the Safe Args Gradle plugin. This plugin generates object and builder classes that enable type-safe navigation between destinations. Use Safe Args for navigating and passing data between destinations.

Enable Safe Args

To add Safe Args to your project, include the following classpath in your top level build.gradle file:

Groovy

buildscript {
    repositories {
        google()
    }
    dependencies {
        def nav_version = "2.9.0"
        classpath "androidx.navigation:navigation-safe-args-gradle-plugin:$nav_version"
    }
}

Kotlin

buildscript {
    repositories {
        google()
    }
    dependencies {
        val nav_version = "2.9.0"
        classpath("androidx.navigation:navigation-safe-args-gradle-plugin:$nav_version")
    }
}

You must also apply one of two available plugins.

To generate Java language code suitable for Java or mixed Java and Kotlin modules, add this line to your app or module's build.gradle file:

Groovy

plugins {
  id 'androidx.navigation.safeargs'
}

Kotlin

plugins {
    id("androidx.navigation.safeargs")
}

Alternatively, to generate Kotlin code suitable for Kotlin-only modules add:

Groovy

plugins {
  id 'androidx.navigation.safeargs.kotlin'
}

Kotlin

plugins {
    id("androidx.navigation.safeargs.kotlin")
}

You must have android.useAndroidX=true in your gradle.properties file as per Migrating to AndroidX.

Generated code

After enabling Safe Args, your generated code contains classes and methods for each action you've defined as well as classes that correspond to each sending and receiving destination.

Safe Args generates a class for each destination where an action originates. The generated class name adds "Directions" to the originating destination class name. For example, if the originating destination is named SpecifyAmountFragment, the generated class is named SpecifyAmountFragmentDirections.

The generated class contains a static method for each action defined in the originating destination. This method takes any defined action parameters as arguments and returns a NavDirections object that you can pass directly to navigate().

Safe Args example

For example, consider a navigation graph with a single action that connects two destinations, SpecifyAmountFragment and ConfirmationFragment. The ConfirmationFragment takes a single float parameter that you provide as part of the action.

Safe Args generates a SpecifyAmountFragmentDirections class with a single method, actionSpecifyAmountFragmentToConfirmationFragment(), and an inner class called ActionSpecifyAmountFragmentToConfirmationFragment. The inner class is derived from NavDirections and stores the associated action ID and float parameter. The returned NavDirections object can then be passed directly to navigate(), as shown in the following example:

Kotlin

override fun onClick(v: View) {
    val amount: Float = ...
    val action =
        SpecifyAmountFragmentDirections
            .actionSpecifyAmountFragmentToConfirmationFragment(amount)
    v.findNavController().navigate(action)
}

Java

@Override
public void onClick(View view) {
    float amount = ...;
    action =
        SpecifyAmountFragmentDirections
            .actionSpecifyAmountFragmentToConfirmationFragment(amount);
    Navigation.findNavController(view).navigate(action);
}

For more information about passing data between destinations with Safe Args, see Use Safe Args to pass data with type safety.

Ensure type safety by using Safe Args

Navigate between destinations using the Safe Args Gradle plugin. This plugin generates simple object and builder classes that enable type-safe navigation and argument passing between destinations.

To add Safe Args to your project, include the following classpath in your top level build.gradle file:

Groovy

buildscript {
    repositories {
        google()
    }
    dependencies {
        def nav_version = "2.9.0"
        classpath "androidx.navigation:navigation-safe-args-gradle-plugin:$nav_version"
    }
}

Kotlin

buildscript {
    repositories {
        google()
    }
    dependencies {
        val nav_version = "2.9.0"
        classpath("androidx.navigation:navigation-safe-args-gradle-plugin:$nav_version")
    }
}

You must also apply one of two available plugins.

To generate Java language code suitable for Java or mixed Java and Kotlin modules, add this line to your app or module's build.gradle file:

Groovy

plugins {
  id 'androidx.navigation.safeargs'
}

Kotlin

plugins {
    id("androidx.navigation.safeargs")
}

Alternatively, to generate Kotlin code suitable for Kotlin-only modules add:

Groovy

plugins {
  id 'androidx.navigation.safeargs.kotlin'
}

Kotlin

plugins {
    id("androidx.navigation.safeargs.kotlin")
}

You must have android.useAndroidX=true in your gradle.properties file as per Migrating to AndroidX.

After you enable Safe Args, the plugin generates code that contains classes and methods for each action you've defined. For each action, Safe Args also generates a class for each originating destination, which is the destination from which the action originates. The generated class name is a combination of the originating destination class name and the word "Directions". For example, if the destination is named SpecifyAmountFragment, the generated class is named SpecifyAmountFragmentDirections. The generated class contains a static method for each action defined in the originating destination. This method takes any defined action parameters as arguments and returns a NavDirections object that you can pass to navigate().

As an example, assume we have a navigation graph with a single action that connects the originating destination, SpecifyAmountFragment, to a receiving destination, ConfirmationFragment.

Safe Args generates a SpecifyAmountFragmentDirections class with a single method, actionSpecifyAmountFragmentToConfirmationFragment(), which returns a NavDirections object. This returned NavDirections object can then be passed directly to navigate(), as shown in the following example:

Kotlin

override fun onClick(view: View) {
    val action =
        SpecifyAmountFragmentDirections
            .actionSpecifyAmountFragmentToConfirmationFragment()
    view.findNavController().navigate(action)
}

Java

@Override
public void onClick(View view) {
    NavDirections action =
        SpecifyAmountFragmentDirections
            .actionSpecifyAmountFragmentToConfirmationFragment();
    Navigation.findNavController(view).navigate(action);
}

For more information on passing data between destinations with Safe Args, see Use Safe Args to pass data with type safety in Pass data between destinations.