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 package com.android.documentsui; 18 19 import android.content.AsyncTaskLoader; 20 import android.content.Context; 21 22 import com.android.documentsui.model.RootInfo; 23 24 import java.util.Collection; 25 26 public class RootsLoader extends AsyncTaskLoader<Collection<RootInfo>> { 27 private final ForceLoadContentObserver mObserver = new ForceLoadContentObserver(); 28 29 private final RootsCache mRoots; 30 private final State mState; 31 32 private Collection<RootInfo> mResult; 33 RootsLoader(Context context, RootsCache roots, State state)34 public RootsLoader(Context context, RootsCache roots, State state) { 35 super(context); 36 mRoots = roots; 37 mState = state; 38 39 getContext().getContentResolver() 40 .registerContentObserver(RootsCache.sNotificationUri, false, mObserver); 41 } 42 43 @Override loadInBackground()44 public final Collection<RootInfo> loadInBackground() { 45 return mRoots.getMatchingRootsBlocking(mState); 46 } 47 48 @Override deliverResult(Collection<RootInfo> result)49 public void deliverResult(Collection<RootInfo> result) { 50 if (isReset()) { 51 return; 52 } 53 54 mResult = result; 55 56 if (isStarted()) { 57 super.deliverResult(result); 58 } 59 } 60 61 @Override onStartLoading()62 protected void onStartLoading() { 63 if (mResult != null) { 64 deliverResult(mResult); 65 } 66 if (takeContentChanged() || mResult == null) { 67 forceLoad(); 68 } 69 } 70 71 @Override onStopLoading()72 protected void onStopLoading() { 73 cancelLoad(); 74 } 75 76 @Override onReset()77 protected void onReset() { 78 super.onReset(); 79 80 // Ensure the loader is stopped 81 onStopLoading(); 82 83 mResult = null; 84 85 getContext().getContentResolver().unregisterContentObserver(mObserver); 86 } 87 } 88