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.roots;
18
19import android.content.AsyncTaskLoader;
20import android.content.BroadcastReceiver;
21import android.content.Context;
22import android.content.Intent;
23import android.content.IntentFilter;
24import android.support.v4.content.LocalBroadcastManager;
25
26import com.android.documentsui.base.RootInfo;
27import com.android.documentsui.base.State;
28
29import java.util.Collection;
30
31public class RootsLoader extends AsyncTaskLoader<Collection<RootInfo>> {
32    private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
33        @Override
34        public void onReceive(Context context, Intent intent) {
35            onContentChanged();
36        }
37    };
38
39    private final ProvidersCache mProviders;
40    private final State mState;
41
42    private Collection<RootInfo> mResult;
43
44    public RootsLoader(Context context, ProvidersCache providers, State state) {
45        super(context);
46        mProviders = providers;
47        mState = state;
48
49        LocalBroadcastManager.getInstance(context).registerReceiver(
50                mReceiver, new IntentFilter(ProvidersAccess.BROADCAST_ACTION));
51    }
52
53    @Override
54    public final Collection<RootInfo> loadInBackground() {
55        return mProviders.getMatchingRootsBlocking(mState);
56    }
57
58    @Override
59    public void deliverResult(Collection<RootInfo> result) {
60        if (isReset()) {
61            return;
62        }
63
64        mResult = result;
65
66        if (isStarted()) {
67            super.deliverResult(result);
68        }
69    }
70
71    @Override
72    protected void onStartLoading() {
73        if (mResult != null) {
74            deliverResult(mResult);
75        }
76        if (takeContentChanged() || mResult == null) {
77            forceLoad();
78        }
79    }
80
81    @Override
82    protected void onStopLoading() {
83        cancelLoad();
84    }
85
86    @Override
87    protected void onReset() {
88        super.onReset();
89
90        // Ensure the loader is stopped
91        onStopLoading();
92
93        mResult = null;
94
95        LocalBroadcastManager.getInstance(getContext()).unregisterReceiver(mReceiver);
96    }
97}
98