How to open a Fragment on button click from a fragment in Android

You can replace the fragment using FragmentTransaction on button click. Something like this:

  Fragment someFragment = new SomeFragment(); 
    FragmentTransaction transaction = getFragmentManager().beginTransaction();
    transaction.replace(R.id.fragment_container, someFragment ); // give your fragment container id in first parameter
    transaction.addToBackStack(null);  // if written, this transaction will be added to backstack
    transaction.commit(); 

Learn about performing fragment transactions here.

code:

  package com.rupomkhondaker.sonalibank;

import android.app.Fragment;
import android.app.FragmentTransaction;
import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;

public class HomeFragment extends Fragment implements View.OnClickListener {

    public HomeFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        View rootView = inflater.inflate(R.layout.fragment_home, container, false);

        Button aboutBtn = (Button) rootView.findViewById(R.id.aboutusButton);
        Button phonebookBtn = (Button) rootView.findViewById(R.id.phbookButton);

        aboutBtn.setOnClickListener(this);
        phonebookBtn.setOnClickListener(this);


        return rootView;
    }

    @Override
    public void onClick(View view) {
        Fragment fragment = null;
        switch (view.getId()) {
            case R.id.aboutusButton:
                fragment = new AboutFragment();
                replaceFragment(fragment);
                break;

            case R.id.phbookButton:
                fragment = new PhoneBookFragment();
                replaceFragment(fragment);
                break;
        }
    }

    public void replaceFragment(Fragment someFragment) {
        FragmentTransaction transaction = getFragmentManager().beginTransaction();
        transaction.replace(R.id.frame_container, someFragment);
        transaction.addToBackStack(null);
        transaction.commit();
    }


}

I have a simple trick to it! This is the code in MainActivity:

Intent intent=new Intent(getApplicationContext(),Main2Activity.class);
        intent.putExtra("pos",1);
        startActivity(intent);

Intent intent1=new Intent(getApplicationContext(),Main2Activity.class);
        intent1.putExtra("pos",2);
        startActivity(intent1);

In Main2Activity which is a NavigationDrawer with fragments

Bundle extras;
  extras=getIntent().getExtras();
        if(extras!=null)
        {
            position=extras.getInt("pos");
            if(position==1)
            {
                fragment=new FragmentOne();

                if(fragment !=null)
                {
                    android.support.v4.app.FragmentManager fragmentManager=getSupportFragmentManager();
                    FragmentTransaction fragmentTransaction=fragmentManager.beginTransaction();
                    fragmentTransaction.replace(R.id.screen_area,fragment);
                    fragmentTransaction.commit();
                }
            }
            if(position==2)
            {
                fragment=new FragmentTwo();

                if(fragment !=null)
                {
                    android.support.v4.app.FragmentManager fragmentManager=getSupportFragmentManager();
                    FragmentTransaction fragmentTransaction=fragmentManager.beginTransaction();
                    fragmentTransaction.replace(R.id.screen_area,fragment);
                    fragmentTransaction.commit();
                }
            }
        }

Kotlin example:

fun FragmentActivity.replaceFragment(fragment: Fragment, frameId: Int = R.id.fragment_container, addToStack: Boolean) {
val doesFragmentAlreadyExists = supportFragmentManager.findFragmentByTag(fragment.javaClass.simpleName) != null
if (!doesFragmentAlreadyExists) {
    supportFragmentManager.inTransaction {
        if (addToStack) replace(frameId, fragment, fragment.javaClass.simpleName)
            .addToBackStack(fragment.javaClass.simpleName)
        else
            replace(frameId, fragment, fragment.javaClass.simpleName)
    }
}}