package com.example.navigationdemo
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.navigation.fragment.NavHostFragment
import androidx.navigation.NavController
class MainActivity : AppCompatActivity() {
private lateinit var navController: NavController
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val navHostFragment = supportFragmentManager
.findFragmentById(R.id.nav_host_fragment) as NavHostFragment
navController = navHostFragment.navController
}
}
// WelcomeFragment.kt
package com.example.navigationdemo
import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.fragment.app.Fragment
import androidx.navigation.fragment.findNavController
import android.widget.Button
class WelcomeFragment : Fragment() {
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?
): View? {
val view = inflater.inflate(R.layout.fragment_welcome, container, false)
val button = view.findViewById<Button>(R.id.button_go_to_details)
button.setOnClickListener {
findNavController().navigate(R.id.action_welcomeFragment_to_detailsFragment)
}
return view
}
}
// DetailsFragment.kt
package com.example.navigationdemo
import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.fragment.app.Fragment
import androidx.navigation.fragment.findNavController
import android.widget.Button
class DetailsFragment : Fragment() {
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?
): View? {
val view = inflater.inflate(R.layout.fragment_details, container, false)
val button = view.findViewById<Button>(R.id.button_back_to_welcome)
button.setOnClickListener {
findNavController().navigate(R.id.action_detailsFragment_to_welcomeFragment)
}
return view
}
}
// activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<fragment
android:id="@+id/nav_host_fragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:navGraph="@navigation/nav_graph"
app:defaultNavHost="true" />
</androidx.constraintlayout.widget.ConstraintLayout>
// fragment_welcome.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="16dp">
<Button
android:id="@+id/button_go_to_details"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Go to Details"
android:layout_gravity="center" />
</FrameLayout>
// fragment_details.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="16dp">
<Button
android:id="@+id/button_back_to_welcome"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Back to Welcome"
android:layout_gravity="center" />
</FrameLayout>
// nav_graph.xml (in res/navigation)
<?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"
android:id="@+id/nav_graph"
app:startDestination="@id/welcomeFragment">
<fragment
android:id="@+id/welcomeFragment"
android:name="com.example.navigationdemo.WelcomeFragment"
android:label="Welcome">
<action
android:id="@+id/action_welcomeFragment_to_detailsFragment"
app:destination="@id/detailsFragment" />
</fragment>
<fragment
android:id="@+id/detailsFragment"
android:name="com.example.navigationdemo.DetailsFragment"
android:label="Details">
<action
android:id="@+id/action_detailsFragment_to_welcomeFragment"
app:destination="@id/welcomeFragment" />
</fragment>
</navigation>This solution uses Android's Navigation component to manage navigation between two fragments.
The NavHostFragment is placed in the activity's layout to host the navigation graph. The NavController is obtained from the NavHostFragment in MainActivity.
Two fragments are created: WelcomeFragment and DetailsFragment. Each fragment has a button that triggers navigation actions defined in the navigation graph XML (nav_graph.xml).
When the user taps the button in WelcomeFragment, the app navigates to DetailsFragment. The button in DetailsFragment navigates back to WelcomeFragment.
This setup follows Android best practices for navigation, keeping UI and navigation logic clean and separate.
