package com.braintreepayments.browserswitch.demo; import android.os.Bundle; import androidx.annotation.Nullable; import androidx.appcompat.app.AppCompatActivity; import androidx.fragment.app.FragmentManager; public class DemoActivity extends AppCompatActivity { private static final String FRAGMENT_TAG = DemoFragment.class.getSimpleName(); @Override protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); FragmentManager fm = getSupportFragmentManager(); if (fm.findFragmentByTag(FRAGMENT_TAG) == null) { fm.beginTransaction() .add(android.R.id.content, new DemoFragment(), FRAGMENT_TAG) .commit(); } } }