Navigation refers to the interactions that allow users to navigate across, into, and back out from the different pieces of content within your app. Android Jetpack’s Navigation component helps you implement navigation, from simple button clicks to more complex patterns, such as app bars and the navigation drawer.
Source: developer.android.com
The navigation component provides a flexible solution to handle the fragments and maintain the backstack.
Features
- Easy to implement.
- Handling Up and Back actions correctly by default.
- Handling fragment transactions.
- Safe Args – a Gradle plugin that provides type safety when navigating and passing data between destinations.
- ViewModel support – you can scope a ViewModel to a navigation graph to share UI-related data between the graph’s destinations.
Implementation
Add to build.gradle(project)
classpath "androidx.navigation:navigation-safe-args-gradle-plugin:2.1.0"
apply the plugin to app-level build.gradle
apply plugin: "androidx.navigation.safeargs.kotlin"
Add dependencies
dependencies {
def nav_version = "2.1.0"
// Kotlin
implementation "androidx.navigation:navigation-fragment-ktx:$nav_version"
implementation "androidx.navigation:navigation-ui-ktx:$nav_version"
}
Navigation without Arguments
Create 2 fragments MainFragment and BasicFragment.
We will navigate to BasicFragment from MainFragment
Create nav_basic.xml
<?xml version="1.0" encoding="utf-8"?>
<navigation xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/nav_basic"
app:startDestination="@id/mainFragment">
<fragment
android:id="@+id/mainFragment"
tools:layout="@layout/fragment_main"
android:name="com.techpaliyal.androidnavigationcomponent.MainFragment">
<action android:id="@+id/startBasicFragment"
app:destination="@id/basicFragment">
</action>
</fragment>
<fragment
android:id="@+id/basicFragment"
tools:layout="@layout/fragment_basic"
android:name="com.techpaliyal.androidnavigationcomponent.BasicFragment"/>
</navigation>
app:startDestination=”@id/mainFragment” this will be the entry point.
action this is used for navigation from mainFragment to basicFragment
Add Navigation fragment to MainActivity
<fragment
android:id="@+id/nav_host_fragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:defaultNavHost="true"
app:navGraph="@navigation/nav_basic" />
Navigate from mainFragment to basicFragment using action id
inside MainFragment.kt on button click
findNavController().navigate(R.id.basicFragment)
findNavController() will give reference to the controller in which the fragment is attached.
Navigation with Arguments
Define arguments in nav_basic.xml
<fragment
android:id="@+id/argumentedFragment"
tools:layout="@layout/fragment_argumented"
android:name="com.techpaliyal.androidnavigationcomponent.ArgumentedFragment">
<argument
android:name="first_name"
app:argType="string" />
</fragment>
Send argument from BasicFragment to ArgumentedFragment
val action = MainFragmentDirections.startArgumentedFragment("Yogesh")
findNavController().navigate(action)
Get arguments in ArgumentedFragment
val params : ArgumentedFragmentArgs by navArgs()
You can check the full code on Github.
Comment for suggestions and issues.
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