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.DocumentsActivity.State; 23 import com.android.documentsui.model.RootInfo; 24 25 import java.util.Collection; 26 27 public class RootsLoader extends AsyncTaskLoader<Collection<RootInfo>> { 28 private final ForceLoadContentObserver mObserver = new ForceLoadContentObserver(); 29 30 private final RootsCache mRoots; 31 private final State mState; 32 33 private Collection<RootInfo> mResult; 34 RootsLoader(Context context, RootsCache roots, State state)35 public RootsLoader(Context context, RootsCache roots, State state) { 36 super(context); 37 mRoots = roots; 38 mState = state; 39 40 getContext().getContentResolver() 41 .registerContentObserver(RootsCache.sNotificationUri, false, mObserver); 42 } 43 44 @Override loadInBackground()45 public final Collection<RootInfo> loadInBackground() { 46 return mRoots.getMatchingRootsBlocking(mState); 47 } 48 49 @Override deliverResult(Collection<RootInfo> result)50 public void deliverResult(Collection<RootInfo> result) { 51 if (isReset()) { 52 return; 53 } 54 Collection<RootInfo> oldResult = mResult; 55 mResult = result; 56 57 if (isStarted()) { 58 super.deliverResult(result); 59 } 60 } 61 62 @Override onStartLoading()63 protected void onStartLoading() { 64 if (mResult != null) { 65 deliverResult(mResult); 66 } 67 if (takeContentChanged() || mResult == null) { 68 forceLoad(); 69 } 70 } 71 72 @Override onStopLoading()73 protected void onStopLoading() { 74 cancelLoad(); 75 } 76 77 @Override onReset()78 protected void onReset() { 79 super.onReset(); 80 81 // Ensure the loader is stopped 82 onStopLoading(); 83 84 mResult = null; 85 86 getContext().getContentResolver().unregisterContentObserver(mObserver); 87 } 88 } 89