Java tutorial
package com.silmood.beatbox; import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentManager; import android.support.v7.app.AppCompatActivity; import android.support.v7.widget.Toolbar; /** * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. * */ public abstract class FragmentContainerActivity extends AppCompatActivity { protected abstract Fragment createFragment(); @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_fragment); FragmentManager fm = getSupportFragmentManager(); Fragment fragment = fm.findFragmentById(R.id.fragment_container); if (fragment == null) { fragment = createFragment(); fm.beginTransaction().add(R.id.fragment_container, fragment).commit(); } } }