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/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.gallery3d.gadget;
import android.content.ContentResolver;
import android.content.Context;
import android.database.ContentObserver;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Environment;
import android.os.Handler;
import android.provider.MediaStore.Images.Media;
import com.android.gallery3d.app.GalleryApp;
import com.android.gallery3d.common.Utils;
import com.android.gallery3d.data.ContentListener;
import com.android.gallery3d.data.DataManager;
import com.android.gallery3d.data.MediaItem;
import com.android.gallery3d.data.Path;
import com.android.gallery3d.util.GalleryUtils;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Random;
public class LocalPhotoSource implements WidgetSource {
@SuppressWarnings("unused")
private static final String TAG = "LocalPhotoSource";
private static final int MAX_PHOTO_COUNT = 128;
/* Static fields used to query for the correct set of images */
private static final Uri CONTENT_URI = Media.EXTERNAL_CONTENT_URI;
private static final String DATE_TAKEN = Media.DATE_TAKEN;
private static final String[] PROJECTION = {Media._ID};
private static final String[] COUNT_PROJECTION = {"count(*)"};
/* We don't want to include the download directory */
private static final String SELECTION =
String.format("%s != %s", Media.BUCKET_ID, getDownloadBucketId());
private static final String ORDER = String.format("%s DESC", DATE_TAKEN);
private Context mContext;
private ArrayList<Long> mPhotos = new ArrayList<Long>();
private ContentListener mContentListener;
private ContentObserver mContentObserver;
private boolean mContentDirty = true;
private DataManager mDataManager;
private static final Path LOCAL_IMAGE_ROOT = Path.fromString("/local/image/item");
public LocalPhotoSource(Context context) {
mContext = context;
mDataManager = ((GalleryApp) context.getApplicationContext()).getDataManager();
mContentObserver = new ContentObserver(new Handler()) {
@Override
public void onChange(boolean selfChange) {
mContentDirty = true;
if (mContentListener != null) mContentListener.onContentDirty();
}
};
mContext.getContentResolver()
.registerContentObserver(CONTENT_URI, true, mContentObserver);
}
@Override
public void close() {
mContext.getContentResolver().unregisterContentObserver(mContentObserver);
}
@Override
public Uri getContentUri(int index) {
if (index < mPhotos.size()) {
return CONTENT_URI.buildUpon()
.appendPath(String.valueOf(mPhotos.get(index)))
.build();
}
return null;
}
@Override
public Bitmap getImage(int index) {
if (index >= mPhotos.size()) return null;
long id = mPhotos.get(index);
MediaItem image = (MediaItem)
mDataManager.getMediaObject(LOCAL_IMAGE_ROOT.getChild(id));
if (image == null) return null;
return WidgetUtils.createWidgetBitmap(image);
}
private int[] getExponentialIndice(int total, int count) {
Random random = new Random();
if (count > total) count = total;
HashSet<Integer> selected = new HashSet<Integer>(count);
while (selected.size() < count) {
int row = (int)(-Math.log(random.nextDouble()) * total / 2);
if (row < total) selected.add(row);
}
int values[] = new int[count];
int index = 0;
for (int value : selected) {
values[index++] = value;
}
return values;
}
private int getPhotoCount(ContentResolver resolver) {
Cursor cursor = resolver.query(
CONTENT_URI, COUNT_PROJECTION, SELECTION, null, null);
if (cursor == null) return 0;
try {
Utils.assertTrue(cursor.moveToNext());
return cursor.getInt(0);
} finally {
cursor.close();
}
}
private boolean isContentSound(int totalCount) {
if (mPhotos.size() < Math.min(totalCount, MAX_PHOTO_COUNT)) return false;
if (mPhotos.size() == 0) return true; // totalCount is also 0
StringBuilder builder = new StringBuilder();
for (Long imageId : mPhotos) {
if (builder.length() > 0) builder.append(",");
builder.append(imageId);
}
Cursor cursor = mContext.getContentResolver().query(
CONTENT_URI, COUNT_PROJECTION,
String.format("%s in (%s)", Media._ID, builder.toString()),
null, null);
if (cursor == null) return false;
try {
Utils.assertTrue(cursor.moveToNext());
return cursor.getInt(0) == mPhotos.size();
} finally {
cursor.close();
}
}
@Override
public void reload() {
if (!mContentDirty) return;
mContentDirty = false;
ContentResolver resolver = mContext.getContentResolver();
int photoCount = getPhotoCount(resolver);
if (isContentSound(photoCount)) return;
int choosedIds[] = getExponentialIndice(photoCount, MAX_PHOTO_COUNT);
Arrays.sort(choosedIds);
mPhotos.clear();
Cursor cursor = mContext.getContentResolver().query(
CONTENT_URI, PROJECTION, SELECTION, null, ORDER);
if (cursor == null) return;
try {
for (int index : choosedIds) {
if (cursor.moveToPosition(index)) {
mPhotos.add(cursor.getLong(0));
}
}
} finally {
cursor.close();
}
}
@Override
public int size() {
reload();
return mPhotos.size();
}
/**
* Builds the bucket ID for the public external storage Downloads directory
* @return the bucket ID
*/
private static int getDownloadBucketId() {
String downloadsPath = Environment
.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS)
.getAbsolutePath();
return GalleryUtils.getBucketId(downloadsPath);
}
@Override
public void setContentListener(ContentListener listener) {
mContentListener = listener;
}
}
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