How to change fragment with the Bottom Navigation Activity?

Question

I created a new project with the "Bottom Navigation Activity":

This is the generated code:

package com.aaron.waller.mrpolitik;

import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v7.app.AppCompatActivity;
import android.view.MenuItem;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    private TextView mTextMessage;

    private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
            = new BottomNavigationView.OnNavigationItemSelectedListener() {

        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            switch (item.getItemId()) {
                case R.id.navigation_home:
                    mTextMessage.setText(R.string.title_home);
                case R.id.navigation_dashboard:
                    mTextMessage.setText(R.string.title_dashboard);
                case R.id.navigation_notifications:
                    mTextMessage.setText(R.string.title_notifications);
            }
            return true;
        }

    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mTextMessage = (TextView) findViewById(R.id.message);
        BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
        navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
    }

}

How can I change to new Fragments with the Bottom Bar? For example I have 3 Fragments: Fragment1 Fragment2 and Fragment3 And I want to change to them with the 3 buttons from the Bottom Bar. Also I want that I can switch the Fragments by swiping my finger left and right how can I do that?

Answer 1

The way I would do it is, I would first add three methods similar to this one (each for a single fragment. Replace the layout name and the fragment object to the appropriate fragment that is being switched to):

public void switchToFragment1() {
    FragmentManager manager = getSupportFragmentManager();
    manager.beginTransaction().replace(R.id.your_fragment_layout_name, new Fragment1()).commit();
}

So your switch statement would end up looking like this:

        switch (item.getItemId()) {
            case R.id.navigation_home:
                mTextMessage.setText(R.string.title_home);
                switchToFragment1();
                break;

            case R.id.navigation_dashboard:
                mTextMessage.setText(R.string.title_dashboard);                    
                switchToFragment2();
                break;

            case R.id.navigation_notifications:
                mTextMessage.setText(R.string.title_notifications);                     
                switchToFragment3();
                break;
        }

As for switching the fragments by swiping to the sides, I believe you would need a ViewPager.