11f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler/* 21f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * Copyright (C) 2013 Google Inc. 31f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * Licensed to The Android Open Source Project. 41f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * 51f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * Licensed under the Apache License, Version 2.0 (the "License"); 61f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * you may not use this file except in compliance with the License. 71f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * You may obtain a copy of the License at 81f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * 91f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * http://www.apache.org/licenses/LICENSE-2.0 101f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * 111f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * Unless required by applicable law or agreed to in writing, software 121f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * distributed under the License is distributed on an "AS IS" BASIS, 131f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 141f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * See the License for the specific language governing permissions and 151f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * limitations under the License. 161f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler */ 171f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler 181f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantlerpackage com.android.mail.ui; 191f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler 201f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantlerimport android.content.AsyncTaskLoader; 211f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantlerimport android.content.Context; 221f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler 231f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler/** 241f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * This class fills in some boilerplate for AsyncTaskLoader to actually load things. 251f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * 261f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * Subclasses need to implement {@link MailAsyncTaskLoader#loadInBackground()} to perform the actual 271f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * background task, and {@link MailAsyncTaskLoader#onDiscardResult(T)} to clean up previously loaded 281f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * results. 291f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler */ 301f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler 311f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantlerpublic abstract class MailAsyncTaskLoader<T> extends AsyncTaskLoader<T> { 321f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler private T mResult; 331f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler 341f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler public MailAsyncTaskLoader(final Context context) { 351f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler super(context); 361f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler } 371f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler 381f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler @Override 391f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler protected void onStartLoading() { 401f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler if (mResult != null) { 411f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler deliverResult(mResult); 421f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler } 431f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler 441f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler if (takeContentChanged() || mResult == null) { 451f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler forceLoad(); 461f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler } 471f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler } 481f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler 491f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler @Override 501f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler protected void onStopLoading() { 511f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler cancelLoad(); 521f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler } 531f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler 541f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler @Override 551f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler public void deliverResult(final T data) { 561f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler if (isReset()) { 571f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler if (data != null) { 581f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler onDiscardResult(data); 591f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler } 601f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler return; 611f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler } 621f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler 631f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler final T oldResult = mResult; 641f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler mResult = data; 651f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler 661f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler if (isStarted()) { 671f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler super.deliverResult(data); 681f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler } 691f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler 701f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler if (oldResult != null && oldResult != mResult) { 711f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler onDiscardResult(oldResult); 721f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler } 731f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler } 741f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler 751f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler @Override 761f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler protected void onReset() { 771f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler super.onReset(); 781f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler 791f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler onStopLoading(); 801f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler 811f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler if (mResult != null) { 821f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler onDiscardResult(mResult); 831f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler } 841f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler mResult = null; 851f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler } 861f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler 871f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler @Override 881f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler public void onCanceled(final T data) { 891f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler super.onCanceled(data); 901f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler 911f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler if (data != null) { 921f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler onDiscardResult(data); 931f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler } 941f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler } 951f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler 961f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler /** 971f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * Called when discarding the load results so subclasses can take care of clean-up or 981f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * recycling tasks. This is not called if the same result (by way of pointer equality) is 991f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * returned again by a subsequent call to loadInBackground, or if result is null. 1001f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * 1011f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * Note that this may be called concurrently with loadInBackground(), and in some circumstances 1021f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * may be called more than once for a given object. 1031f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * 1041f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * @param result The value returned from {@link MailAsyncTaskLoader#loadInBackground()} which 1051f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler * is to be discarded. 1061f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler */ 1071f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler protected abstract void onDiscardResult(final T result); 1081f1239b94b2417fc9395f7b2139dc2180aaf3578Tony Mantler} 109