1 /* 2 * Copyright (C) 2011 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.gallery3d.gadget; 18 19 import android.content.ContentResolver; 20 import android.content.Context; 21 import android.database.ContentObserver; 22 import android.database.Cursor; 23 import android.graphics.Bitmap; 24 import android.net.Uri; 25 import android.os.Environment; 26 import android.os.Handler; 27 import android.provider.MediaStore.Images.Media; 28 29 import com.android.gallery3d.app.GalleryApp; 30 import com.android.gallery3d.common.Utils; 31 import com.android.gallery3d.data.ContentListener; 32 import com.android.gallery3d.data.DataManager; 33 import com.android.gallery3d.data.MediaItem; 34 import com.android.gallery3d.data.Path; 35 import com.android.gallery3d.util.GalleryUtils; 36 37 import java.util.ArrayList; 38 import java.util.Arrays; 39 import java.util.HashSet; 40 import java.util.Random; 41 42 public class LocalPhotoSource implements WidgetSource { 43 44 @SuppressWarnings("unused") 45 private static final String TAG = "LocalPhotoSource"; 46 47 private static final int MAX_PHOTO_COUNT = 128; 48 49 /* Static fields used to query for the correct set of images */ 50 private static final Uri CONTENT_URI = Media.EXTERNAL_CONTENT_URI; 51 private static final String DATE_TAKEN = Media.DATE_TAKEN; 52 private static final String[] PROJECTION = {Media._ID}; 53 private static final String[] COUNT_PROJECTION = {"count(*)"}; 54 /* We don't want to include the download directory */ 55 private static final String SELECTION = 56 String.format("%s != %s", Media.BUCKET_ID, getDownloadBucketId()); 57 private static final String ORDER = String.format("%s DESC", DATE_TAKEN); 58 59 private Context mContext; 60 private ArrayList<Long> mPhotos = new ArrayList<Long>(); 61 private ContentListener mContentListener; 62 private ContentObserver mContentObserver; 63 private boolean mContentDirty = true; 64 private DataManager mDataManager; 65 private static final Path LOCAL_IMAGE_ROOT = Path.fromString("/local/image/item"); 66 67 public LocalPhotoSource(Context context) { 68 mContext = context; 69 mDataManager = ((GalleryApp) context.getApplicationContext()).getDataManager(); 70 mContentObserver = new ContentObserver(new Handler()) { 71 @Override 72 public void onChange(boolean selfChange) { 73 mContentDirty = true; 74 if (mContentListener != null) mContentListener.onContentDirty(); 75 } 76 }; 77 mContext.getContentResolver() 78 .registerContentObserver(CONTENT_URI, true, mContentObserver); 79 } 80 81 @Override 82 public void close() { 83 mContext.getContentResolver().unregisterContentObserver(mContentObserver); 84 } 85 86 @Override 87 public Uri getContentUri(int index) { 88 if (index < mPhotos.size()) { 89 return CONTENT_URI.buildUpon() 90 .appendPath(String.valueOf(mPhotos.get(index))) 91 .build(); 92 } 93 return null; 94 } 95 96 @Override 97 public Bitmap getImage(int index) { 98 if (index >= mPhotos.size()) return null; 99 long id = mPhotos.get(index); 100 MediaItem image = (MediaItem) 101 mDataManager.getMediaObject(LOCAL_IMAGE_ROOT.getChild(id)); 102 if (image == null) return null; 103 104 return WidgetUtils.createWidgetBitmap(image); 105 } 106 107 private int[] getExponentialIndice(int total, int count) { 108 Random random = new Random(); 109 if (count > total) count = total; 110 HashSet<Integer> selected = new HashSet<Integer>(count); 111 while (selected.size() < count) { 112 int row = (int)(-Math.log(random.nextDouble()) * total / 2); 113 if (row < total) selected.add(row); 114 } 115 int values[] = new int[count]; 116 int index = 0; 117 for (int value : selected) { 118 values[index++] = value; 119 } 120 return values; 121 } 122 123 private int getPhotoCount(ContentResolver resolver) { 124 Cursor cursor = resolver.query( 125 CONTENT_URI, COUNT_PROJECTION, SELECTION, null, null); 126 if (cursor == null) return 0; 127 try { 128 Utils.assertTrue(cursor.moveToNext()); 129 return cursor.getInt(0); 130 } finally { 131 cursor.close(); 132 } 133 } 134 135 private boolean isContentSound(int totalCount) { 136 if (mPhotos.size() < Math.min(totalCount, MAX_PHOTO_COUNT)) return false; 137 if (mPhotos.size() == 0) return true; // totalCount is also 0 138 139 StringBuilder builder = new StringBuilder(); 140 for (Long imageId : mPhotos) { 141 if (builder.length() > 0) builder.append(","); 142 builder.append(imageId); 143 } 144 Cursor cursor = mContext.getContentResolver().query( 145 CONTENT_URI, COUNT_PROJECTION, 146 String.format("%s in (%s)", Media._ID, builder.toString()), 147 null, null); 148 if (cursor == null) return false; 149 try { 150 Utils.assertTrue(cursor.moveToNext()); 151 return cursor.getInt(0) == mPhotos.size(); 152 } finally { 153 cursor.close(); 154 } 155 } 156 157 @Override 158 public void reload() { 159 if (!mContentDirty) return; 160 mContentDirty = false; 161 162 ContentResolver resolver = mContext.getContentResolver(); 163 int photoCount = getPhotoCount(resolver); 164 if (isContentSound(photoCount)) return; 165 166 int choosedIds[] = getExponentialIndice(photoCount, MAX_PHOTO_COUNT); 167 Arrays.sort(choosedIds); 168 169 mPhotos.clear(); 170 Cursor cursor = mContext.getContentResolver().query( 171 CONTENT_URI, PROJECTION, SELECTION, null, ORDER); 172 if (cursor == null) return; 173 try { 174 for (int index : choosedIds) { 175 if (cursor.moveToPosition(index)) { 176 mPhotos.add(cursor.getLong(0)); 177 } 178 } 179 } finally { 180 cursor.close(); 181 } 182 } 183 184 @Override 185 public int size() { 186 reload(); 187 return mPhotos.size(); 188 } 189 190 /** 191 * Builds the bucket ID for the public external storage Downloads directory 192 * @return the bucket ID 193 */ 194 private static int getDownloadBucketId() { 195 String downloadsPath = Environment 196 .getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS) 197 .getAbsolutePath(); 198 return GalleryUtils.getBucketId(downloadsPath); 199 } 200 201 @Override 202 public void setContentListener(ContentListener listener) { 203 mContentListener = listener; 204 } 205 } 206
