1 /* 2 * Copyright (C) 2012 Google Inc. 3 * Licensed to The Android Open Source Project. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package com.android.mail.ui; 19 20 import android.app.Activity; 21 import android.content.AsyncTaskLoader; 22 import android.net.Uri; 23 24 import com.android.mail.browse.ConversationCursor; 25 import com.android.mail.providers.Account; 26 import com.android.mail.providers.UIProvider.AccountCapabilities; 27 import com.android.mail.utils.LogUtils; 28 29 import java.util.ArrayList; 30 31 public class ConversationCursorLoader extends AsyncTaskLoader<ConversationCursor> { 32 private static final String TAG = "ConversationCursorLoader"; 33 private final Uri mUri; 34 private final ConversationCursor mConversationCursor; 35 private boolean mInit = false; 36 private boolean mClosed = false; 37 private boolean mRetain = false; 38 private boolean mRetained = false; 39 private final String mName; 40 41 /** Only used for debugging. Turn {@link #DEBUG} on to make this useful. */ 42 private static final boolean DEBUG = false; 43 private static final ArrayList<ConversationCursorLoader> sLoaders = 44 new ArrayList<ConversationCursorLoader>(); 45 ConversationCursorLoader(Activity activity, Account account, Uri uri, String name, boolean ignoreInitialConversationLimit)46 public ConversationCursorLoader(Activity activity, Account account, 47 Uri uri, String name, boolean ignoreInitialConversationLimit) { 48 super(activity); 49 mUri = uri; 50 mName = name; 51 final boolean useInitialConversationLimit = ignoreInitialConversationLimit ? false : 52 account.supportsCapability(AccountCapabilities.INITIAL_CONVERSATION_LIMIT); 53 // Initialize the state of the conversation cursor 54 mConversationCursor = new ConversationCursor( 55 activity, mUri, useInitialConversationLimit, name); 56 addLoader(); 57 } 58 dumpLoaders()59 private static void dumpLoaders() { 60 if (DEBUG) { 61 LogUtils.d(TAG, "Loaders: "); 62 for (ConversationCursorLoader loader: sLoaders) { 63 LogUtils.d(TAG, " >> " + loader.mName + " (" + loader.mUri + ")"); 64 } 65 } 66 } 67 addLoader()68 private void addLoader() { 69 if (DEBUG) { 70 LogUtils.d(TAG, "Add loader: " + mUri); 71 sLoaders.add(this); 72 if (sLoaders.size() > 1) { 73 dumpLoaders(); 74 } 75 } 76 } 77 78 /** 79 * Indicate whether the loader's cursor should be retained after reset 80 * @param state whether this laoder's cursor should be retained 81 */ retainCursor(boolean state)82 public void retainCursor(boolean state) { 83 mRetain = state; 84 } 85 86 @Override onReset()87 public void onReset() { 88 if (!mRetain) { 89 // Mark the cursor as disabled 90 mConversationCursor.disable(); 91 mClosed = true; 92 if (DEBUG) { 93 LogUtils.d(TAG, "Reset loader/disable cursor: " + mName); 94 sLoaders.remove(this); 95 if (!sLoaders.isEmpty()) { 96 dumpLoaders(); 97 } 98 } 99 } else { 100 if (DEBUG) { 101 LogUtils.d(TAG, "Reset loader/retain cursor: " + mName); 102 mRetained = true; 103 } 104 } 105 } 106 107 @Override loadInBackground()108 public ConversationCursor loadInBackground() { 109 if (!mInit) { 110 mConversationCursor.load(); 111 mInit = true; 112 } 113 return mConversationCursor; 114 } 115 116 @Override onStartLoading()117 protected void onStartLoading() { 118 if (mClosed) { 119 mClosed = false; 120 mConversationCursor.load(); 121 addLoader(); 122 if (DEBUG) { 123 LogUtils.d(TAG, "Restarting reset loader: " + mName); 124 } 125 } else if (mRetained) { 126 mRetained = false; 127 if (DEBUG) { 128 LogUtils.d(TAG, "Resuming retained loader: " + mName); 129 } 130 } 131 forceLoad(); 132 mConversationCursor.resume(); 133 } 134 135 @Override onStopLoading()136 protected void onStopLoading() { 137 cancelLoad(); 138 mConversationCursor.pause(); 139 } 140 } 141