1 /* 2 * Copyright (C) 2012 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.example.android.bitmapfun.util; 18 19 import android.os.Bundle; 20 import android.support.v4.app.Fragment; 21 import android.support.v4.app.FragmentManager; 22 23 /** 24 * A simple non-UI Fragment that stores a single Object and is retained over configuration changes. 25 * In this sample it will be used to retain the ImageCache object. 26 */ 27 public class RetainFragment extends Fragment { 28 private static final String TAG = "RetainFragment"; 29 private Object mObject; 30 31 /** 32 * Empty constructor as per the Fragment documentation 33 */ RetainFragment()34 public RetainFragment() {} 35 36 /** 37 * Locate an existing instance of this Fragment or if not found, create and 38 * add it using FragmentManager. 39 * 40 * @param fm The FragmentManager manager to use. 41 * @return The existing instance of the Fragment or the new instance if just 42 * created. 43 */ findOrCreateRetainFragment(FragmentManager fm)44 public static RetainFragment findOrCreateRetainFragment(FragmentManager fm) { 45 // Check to see if we have retained the worker fragment. 46 RetainFragment mRetainFragment = (RetainFragment) fm.findFragmentByTag(TAG); 47 48 // If not retained (or first time running), we need to create and add it. 49 if (mRetainFragment == null) { 50 mRetainFragment = new RetainFragment(); 51 fm.beginTransaction().add(mRetainFragment, TAG).commit(); 52 } 53 54 return mRetainFragment; 55 } 56 57 @Override onCreate(Bundle savedInstanceState)58 public void onCreate(Bundle savedInstanceState) { 59 super.onCreate(savedInstanceState); 60 61 // Make sure this Fragment is retained over a configuration change 62 setRetainInstance(true); 63 } 64 65 /** 66 * Store a single object in this Fragment. 67 * 68 * @param object The object to store 69 */ setObject(Object object)70 public void setObject(Object object) { 71 mObject = object; 72 } 73 74 /** 75 * Get the stored object. 76 * 77 * @return The stored object 78 */ getObject()79 public Object getObject() { 80 return mObject; 81 } 82 83 } 84