1 /* 2 * Copyright (C) 2013 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 18 package com.android.mail.providers; 19 20 import com.android.mail.ui.AccountController; 21 import com.android.mail.utils.LogTag; 22 import com.android.mail.utils.LogUtils; 23 24 import android.database.DataSetObserver; 25 26 /** 27 * A simple extension of {@link android.database.DataSetObserver} to provide all Accounts in 28 * {@link #onChanged(Account[])} when the list of Accounts changes. Initializing the object 29 * registers with the observer with the {@link com.android.mail.ui.AccountController} provided. 30 * The object will then begin to receive {@link #onChanged(Account[])} till {@link 31 * #unregisterAndDestroy()} is called. <p> To implement an {@link com.android.mail.providers 32 * .AllAccountObserver}, you need to implement the {@link #onChanged(Account[])} method. 33 */ 34 public abstract class AllAccountObserver extends DataSetObserver { 35 /** 36 * The AccountController that the observer is registered with. 37 */ 38 private AccountController mController; 39 40 private static final String LOG_TAG = LogTag.getLogTag(); 41 42 /** 43 * The no-argument constructor leaves the object unusable till 44 * {@link #initialize(com.android.mail.ui.AccountController)} is called. 45 */ 46 public AllAccountObserver() { 47 } 48 49 /** 50 * Initializes an {@link com.android.mail.providers.AllAccountObserver} object that receives 51 * a call to {@link #onChanged(Account[])} when the controller changes the list of accounts. 52 * 53 * @param controller 54 */ 55 public Account[] initialize(AccountController controller) { 56 if (controller == null) { 57 LogUtils.wtf(LOG_TAG, "AllAccountObserver initialized with null controller!"); 58 } 59 mController = controller; 60 mController.registerAllAccountObserver(this); 61 return mController.getAllAccounts(); 62 } 63 64 @Override 65 public final void onChanged() { 66 if (mController == null) { 67 return; 68 } 69 onChanged(mController.getAllAccounts()); 70 } 71 72 /** 73 * Callback invoked when the list of Accounts changes. 74 * The updated list is passed as the argument. 75 * @param allAccounts the array of all accounts in the current application. 76 */ 77 public abstract void onChanged(Account[] allAccounts); 78 79 /** 80 * Return the array of existing accounts. 81 * @return the array of existing accounts. 82 */ 83 public final Account[] getAllAccounts() { 84 if (mController == null) { 85 return null; 86 } 87 return mController.getAllAccounts(); 88 } 89 90 /** 91 * Unregisters for list of Account changes and makes the object unusable. 92 */ 93 public void unregisterAndDestroy() { 94 if (mController == null) { 95 return; 96 } 97 mController.unregisterAllAccountObserver(this); 98 } 99 } 100
