package com.tecent.bottomnavigationviewexample;
 
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v4.app.Fragment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MenuItem;
 
public class MainActivity extends AppCompatActivity {
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        BottomNavigationView bottomNav = findViewById(R.id.bottom_navigation_view);
        bottomNav.setOnNavigationItemSelectedListener(navListener);
 
        //I added this if statement to keep the selected fragment when rotating the device
        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
                    new HomeFragment()).commit();
        }
    }
 
    private BottomNavigationView.OnNavigationItemSelectedListener navListener =
            new BottomNavigationView.OnNavigationItemSelectedListener() {
                @Override
                public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                    Fragment selectedFragment = null;
 
                    switch (item.getItemId()) {
                        case R.id.nav_home:
                            selectedFragment = new HomeFragment();
                            break;
                        case R.id.nav_dashboard:
                            selectedFragment = new DashBoardFragment();
                            break;
                        case R.id.nav_test_series:
                            selectedFragment = new TestSeriesFragment();
                            break;
                        case R.id.nav_doubt:
                            selectedFragment = new DoubtsFragment();
                            break;
                    }
 
                    getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
                            selectedFragment).commit();
 
                    return true;
                }
            };
}