| /* |
| * Copyright (C) 2013 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.dreams.phototable; |
| |
| import android.content.Context; |
| import android.content.SharedPreferences; |
| import android.database.Cursor; |
| |
| /** |
| * Common implementation for sources that load images from a cursor. |
| */ |
| public abstract class CursorPhotoSource extends PhotoSource { |
| |
| // An invalid cursor position to represent the uninitialized state. |
| protected static final int UNINITIALIZED = -1; |
| // An invalid cursor position to represent the error state. |
| protected static final int INVALID = -2; |
| |
| public CursorPhotoSource(Context context, SharedPreferences settings) { |
| super(context, settings); |
| } |
| |
| public CursorPhotoSource(Context context, SharedPreferences settings, PhotoSource fallback) { |
| super(context, settings, fallback); |
| } |
| |
| @Override |
| protected ImageData naturalNext(ImageData current) { |
| if (current.cursor == null || current.cursor.isClosed()) { |
| openCursor(current); |
| } |
| findPosition(current); |
| current.cursor.moveToPosition(current.position); |
| current.cursor.moveToNext(); |
| ImageData data = null; |
| if (!current.cursor.isAfterLast()) { |
| data = unpackImageData(current.cursor, null); |
| data.cursor = current.cursor; |
| data.position = current.cursor.getPosition(); |
| } |
| return data; |
| } |
| |
| @Override |
| protected ImageData naturalPrevious(ImageData current) { |
| if (current.cursor == null || current.cursor.isClosed()) { |
| openCursor(current); |
| } |
| findPosition(current); |
| current.cursor.moveToPosition(current.position); |
| current.cursor.moveToPrevious(); |
| ImageData data = null; |
| if (!current.cursor.isBeforeFirst()) { |
| data = unpackImageData(current.cursor, null); |
| data.cursor = current.cursor; |
| data.position = current.cursor.getPosition(); |
| } |
| return data; |
| } |
| |
| @Override |
| protected void donePaging(ImageData current) { |
| if (current.cursor != null && !current.cursor.isClosed()) { |
| current.cursor.close(); |
| } |
| } |
| |
| protected abstract void openCursor(ImageData data); |
| protected abstract void findPosition(ImageData data); |
| protected abstract ImageData unpackImageData(Cursor cursor, ImageData data); |
| } |
| |