content: /*
   * Copyright 2017, The Android Open Source Project
   *
   * Licensed 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.
   */
  
  package com.example.android.persistence.ui;
  
  import android.os.Bundle;
  import androidx.annotation.Nullable;
  import androidx.appcompat.app.AppCompatActivity;
  
  import com.example.android.persistence.R;
  import com.example.android.persistence.model.Product;
  
  public class MainActivity extends AppCompatActivity {
      @Override
      protected void onCreate(@Nullable Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.main_activity);
  
          // Add product list fragment if this is first creation
          if (savedInstanceState == null) {
              ProductListFragment fragment = new ProductListFragment();
  
              getSupportFragmentManager().beginTransaction()
                      .add(R.id.fragment_container, fragment, ProductListFragment.TAG).commit();
          }
      }
  
      /** Shows the product detail fragment */
      public void show(Product product) {
  
          ProductFragment productFragment = ProductFragment.forProduct(product.getId());
  
          getSupportFragmentManager()
                  .beginTransaction()
                  .addToBackStack("product")
                  .replace(R.id.fragment_container,
                          productFragment, null).commit();
      }
  }
  