1 /*
2  * Copyright (C) 2010 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 package com.android.contacts.list;
17 
18 import android.content.Context;
19 import android.content.CursorLoader;
20 import android.database.Cursor;
21 import android.database.CursorWrapper;
22 import android.net.Uri;
23 
24 /**
25  * A specialized loader for the Join Contacts UI.  It executes two queries:
26  * join suggestions and (optionally) the full contact list.
27  *
28  * This loader also loads the "suggestion" cursor, which can be accessed with:
29  * {@code ((JoinContactLoaderResult) result).suggestionCursor }
30  */
31 public class JoinContactLoader extends CursorLoader {
32 
33     private String[] mProjection;
34     private Uri mSuggestionUri;
35 
36     /**
37      * Actual returned class.  It's guaranteed that this loader always returns an instance of this
38      * class.  This class is needed to tie the lifecycle of the second cursor to that of the
39      * primary one.
40      *
41      * Note we can't change the result type of this loader itself, because CursorLoader
42      * extends AsyncTaskLoader<Cursor>, not AsyncTaskLoader<? extends Cursor>
43      */
44     public static class JoinContactLoaderResult extends CursorWrapper {
45         public final Cursor suggestionCursor;
46 
JoinContactLoaderResult(Cursor baseCursor, Cursor suggestionCursor)47         public JoinContactLoaderResult(Cursor baseCursor, Cursor suggestionCursor) {
48             super(baseCursor);
49             this.suggestionCursor = suggestionCursor;
50         }
51 
52         @Override
close()53         public void close() {
54             try {
55                 if (suggestionCursor != null) {
56                     suggestionCursor.close();
57                 }
58             } finally {
59                 if (super.getWrappedCursor() != null) {
60                     super.close();
61                 }
62             }
63         }
64     }
65 
JoinContactLoader(Context context)66     public JoinContactLoader(Context context) {
67         super(context, null, null, null, null, null);
68     }
69 
setSuggestionUri(Uri uri)70     public void setSuggestionUri(Uri uri) {
71         this.mSuggestionUri = uri;
72     }
73 
74     @Override
setProjection(String[] projection)75     public void setProjection(String[] projection) {
76         super.setProjection(projection);
77         this.mProjection = projection;
78     }
79 
80     @Override
loadInBackground()81     public Cursor loadInBackground() {
82         // First execute the suggestions query, then call super.loadInBackground
83         // to load the entire list
84         final Cursor suggestionsCursor = getContext().getContentResolver()
85                 .query(mSuggestionUri, mProjection, null, null, null);
86         if (suggestionsCursor == null) {
87             return null;
88         }
89         Cursor cursorToClose = suggestionsCursor;
90         try {
91             final Cursor baseCursor = super.loadInBackground();
92             if (baseCursor != null) {
93                 final JoinContactLoaderResult result =
94                         new JoinContactLoaderResult(baseCursor, suggestionsCursor);
95                 cursorToClose = null;
96                 return result;
97             }
98         } finally {
99             if (cursorToClose != null) {
100                 cursorToClose.close();
101             }
102         }
103         return null;
104     }
105 }
106