Simple application of android,jetpack’s Navigation

package com.example.mynavigationdemo;

import android.os.Bundle;

import androidx.appcompat.app.AppCompatActivity;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.navigation.ui.NavigationUI;

public class MainActivity extends AppCompatActivity {<!-- -->

    @Override
    protected void onCreate(Bundle savedInstanceState) {<!-- -->
        super.onCreate(savedInstanceState);
        setContentView(R. layout. activity_main);
        NavController navController = Navigation.findNavController(this, R.id.fragment);
        NavigationUI.setupActionBarWithNavController(this,navController);
    }

    @Override
    public boolean onSupportNavigateUp() {<!-- -->
        NavController navController = Navigation.findNavController(this, R.id.fragment);
        return navController.navigateUp();
    }
}

package com.example.mynavigationdemo;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;

import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;


public class HomeFragment extends Fragment {<!-- -->


    public HomeFragment() {<!-- -->
        // Required empty public constructor
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {<!-- -->
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_home, container, false);
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {<!-- -->
        super.onActivityCreated(savedInstanceState);
        Button button = getView().findViewById(R.id.button);
        button.setOnClickListener((v)->{<!-- -->
            /*Bundle args = new Bundle();
            args. putString("user_name","jack");*/
            Bundle args = new HomeFragmentArgs.Builder()
                    .setUserName("rose")
                    .setAge(18)
                    .build().toBundle();
            NavController navController = Navigation. findNavController(v);
            navController.navigate(R.id.action_homeFragment_to_detailFragment, args);
        });
    }
}

package com.example.mynavigationdemo;

import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;

import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;


public class DetailFragment extends Fragment {<!-- -->


    public DetailFragment() {<!-- -->
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {<!-- -->
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_detail, container, false);
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {<!-- -->
        super.onActivityCreated(savedInstanceState);
        Button button = getView().findViewById(R.id.button2);
        /*Bundle args = getArguments();
        String userName = args. getString("user_name");*/
        //Log.d("ning","userName:" + userName);

        HomeFragmentArgs args = HomeFragmentArgs. fromBundle(getArguments());
        String userName = args. getUserName();
        int age = args. getAge();
        Log.d("ning",userName + "," + age);

        button.setOnClickListener((v)->{<!-- -->
            NavController navController = Navigation. findNavController(v);
            navController.navigate(R.id.action_detailFragment_to_homeFragment);
        });
    }
}

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <fragment
        android:id="@ + id/fragment"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:defaultNavHost="true"
        app:navGraph="@navigation/my_nav_graph" />
</androidx.constraintlayout.widget.ConstraintLayout>

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".DetailFragment">


    <Button
        android:id="@ + id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".HomeFragment">


    <Button
        android:id="@ + id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

<?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/my_nav_graph"
    app:startDestination="@id/homeFragment">

    <fragment
        android:id="@ + id/homeFragment"
        android:name="com.example.mynavigationdemo.HomeFragment"
        android:label="fragment_home"
        tools:layout="@layout/fragment_home" >
        <action
            android:id="@ + id/action_homeFragment_to_detailFragment"
            app:destination="@id/detailFragment"
            app:enterAnim="@anim/nav_default_enter_anim"
            app:exitAnim="@anim/nav_default_exit_anim" />
        <argument
            android:name="user_name"
            app:argType="string"
            android:defaultValue="unknown"/>
        <argument
            android:name="age"
            app:argType="integer"
            android:defaultValue="0"/>
    </fragment>
    <fragment
        android:id="@ + id/detailFragment"
        android:name="com.example.mynavigationdemo.DetailFragment"
        android:label="fragment_detail"
        tools:layout="@layout/fragment_detail" >
        <action
            android:id="@ + id/action_detailFragment_to_homeFragment"
            app:destination="@id/homeFragment" />
    </fragment>
</navigation>

Some notes on adding dependencies are as follows: