how to start fragment from activity code example

Example 1: how to start a fragment

HomeFragment fragment1 = new HomeFragment();
        FragmentTransaction ft1 = getSupportFragmentManager().beginTransaction();
        ft1.replace(R.id.content, fragment1, "");
        ft1.commit();

Example 2: start fragment from activity

FragmentManager manager = getFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.add(R.id.container,YOUR_FRAGMENT_NAME,YOUR_FRAGMENT_STRING_TAG);
transaction.addToBackStack(null);
transaction.commit();

Example 3: change fragment in android studio

// put the following code in onClickListner
// public void onClickListner(View view){
Navigation.findNavController(view).navigate(R.id.action_fromFragment_toFragment);
// action_fromFragment_toFragment is the id of transformatino, look in fragment map.
// }