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 17package com.android.documentsui; 18 19import android.content.AsyncTaskLoader; 20import android.content.Context; 21 22import com.android.documentsui.DocumentsActivity.State; 23import com.android.documentsui.model.RootInfo; 24 25import java.util.Collection; 26 27public class RootsLoader extends AsyncTaskLoader<Collection<RootInfo>> { 28 private final RootsCache mRoots; 29 private final State mState; 30 31 private Collection<RootInfo> mResult; 32 33 public RootsLoader(Context context, RootsCache roots, State state) { 34 super(context); 35 mRoots = roots; 36 mState = state; 37 } 38 39 @Override 40 public final Collection<RootInfo> loadInBackground() { 41 return mRoots.getMatchingRootsBlocking(mState); 42 } 43 44 @Override 45 public void deliverResult(Collection<RootInfo> result) { 46 if (isReset()) { 47 return; 48 } 49 Collection<RootInfo> oldResult = mResult; 50 mResult = result; 51 52 if (isStarted()) { 53 super.deliverResult(result); 54 } 55 } 56 57 @Override 58 protected void onStartLoading() { 59 if (mResult != null) { 60 deliverResult(mResult); 61 } 62 if (takeContentChanged() || mResult == null) { 63 forceLoad(); 64 } 65 } 66 67 @Override 68 protected void onStopLoading() { 69 cancelLoad(); 70 } 71 72 @Override 73 protected void onReset() { 74 super.onReset(); 75 76 // Ensure the loader is stopped 77 onStopLoading(); 78 79 mResult = null; 80 } 81} 82