src/com/android/camera/PhotoAppWidgetProvider.java

/*
 * Copyright (C) 2009 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.camera;

import com.android.gallery.R;

import android.appwidget.AppWidgetManager;
import android.appwidget.AppWidgetProvider;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;
import android.widget.RemoteViews;

import java.io.ByteArrayOutputStream;
import java.io.IOException;

/**
 * Simple widget to show a user-selected picture.
 */
public class PhotoAppWidgetProvider extends AppWidgetProvider {
    private static final String TAG = "PhotoAppWidgetProvider";
    private static final boolean LOGD = true;

    @Override
    public void onUpdate(Context context, AppWidgetManager appWidgetManager,
                         int[] appWidgetIds) {
        // Update each requested appWidgetId with its unique photo
        PhotoDatabaseHelper helper = new PhotoDatabaseHelper(context);
        for (int appWidgetId : appWidgetIds) {
            int[] specificAppWidget = new int[] { appWidgetId };
            RemoteViews views = buildUpdate(context, appWidgetId, helper);
            if (LOGD) {
                Log.d(TAG, "sending out views=" + views
                        + " for id=" + appWidgetId);
            }
            appWidgetManager.updateAppWidget(specificAppWidget, views);
        }
        helper.close();
    }

    @Override
    public void onDeleted(Context context, int[] appWidgetIds) {
        // Clean deleted photos out of our database
        PhotoDatabaseHelper helper = new PhotoDatabaseHelper(context);
        for (int appWidgetId : appWidgetIds) {
            helper.deletePhoto(appWidgetId);
        }
        helper.close();
    }

    /**
     * Load photo for given widget and build {@link RemoteViews} for it.
     */
    static RemoteViews buildUpdate(Context context, int appWidgetId,
                                   PhotoDatabaseHelper helper) {
        RemoteViews views = null;
        Bitmap bitmap = helper.getPhoto(appWidgetId);
        if (bitmap != null) {
            views = new RemoteViews(context.getPackageName(),
                                    R.layout.photo_frame);
            views.setImageViewBitmap(R.id.photo, bitmap);
        }
        return views;
    }

    static class PhotoDatabaseHelper extends SQLiteOpenHelper {
        private static final String DATABASE_NAME = "launcher.db";

        private static final int DATABASE_VERSION = 2;

        static final String TABLE_PHOTOS = "photos";
        static final String FIELD_APPWIDGET_ID = "appWidgetId";
        static final String FIELD_PHOTO_BLOB = "photoBlob";

        PhotoDatabaseHelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }

        @Override
        public void onCreate(SQLiteDatabase db) {
            db.execSQL("CREATE TABLE " + TABLE_PHOTOS + " (" +
                    FIELD_APPWIDGET_ID + " INTEGER PRIMARY KEY," +
                    FIELD_PHOTO_BLOB + " BLOB" +
                    ");");
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion,
                              int newVersion) {
            int version = oldVersion;

            if (version != DATABASE_VERSION) {
                Log.w(TAG, "Destroying all old data.");
                db.execSQL("DROP TABLE IF EXISTS " + TABLE_PHOTOS);
                onCreate(db);
            }
        }

        /**
         * Store the given bitmap in this database for the given appWidgetId.
         */
        public boolean setPhoto(int appWidgetId, Bitmap bitmap) {
            boolean success = false;
            try {
                // Try go guesstimate how much space the icon will take when
                // serialized to avoid unnecessary allocations/copies during
                // the write.
                int size = bitmap.getWidth() * bitmap.getHeight() * 4;
                ByteArrayOutputStream out = new ByteArrayOutputStream(size);
                bitmap.compress(Bitmap.CompressFormat.PNG, 100, out);
                out.flush();
                out.close();

                ContentValues values = new ContentValues();
                values.put(PhotoDatabaseHelper.FIELD_APPWIDGET_ID, appWidgetId);
                values.put(PhotoDatabaseHelper.FIELD_PHOTO_BLOB,
                           out.toByteArray());

                SQLiteDatabase db = getWritableDatabase();
                db.insertOrThrow(PhotoDatabaseHelper.TABLE_PHOTOS, null,
                                 values);

                success = true;
            } catch (SQLiteException e) {
                Log.e(TAG, "Could not open database", e);
            } catch (IOException e) {
                Log.e(TAG, "Could not serialize photo", e);
            }
            if (LOGD) {
                Log.d(TAG, "setPhoto success=" + success);
            }
            return success;
        }

        static final String[] PHOTOS_PROJECTION = {
            FIELD_PHOTO_BLOB,
        };

        static final int INDEX_PHOTO_BLOB = 0;

        /**
         * Inflate and return a bitmap for the given appWidgetId.
         */
        public Bitmap getPhoto(int appWidgetId) {
            Cursor c = null;
            Bitmap bitmap = null;
            try {
                SQLiteDatabase db = getReadableDatabase();
                String selection = String.format("%s=%d", FIELD_APPWIDGET_ID,
                                                 appWidgetId);
                c = db.query(TABLE_PHOTOS, PHOTOS_PROJECTION, selection, null,
                        null, null, null, null);

                if (c != null && LOGD) {
                    Log.d(TAG, "getPhoto query count=" + c.getCount());
                }

                if (c != null && c.moveToFirst()) {
                    byte[] data = c.getBlob(INDEX_PHOTO_BLOB);
                    if (data != null) {
                        bitmap = BitmapFactory.decodeByteArray(data, 0,
                                data.length);
                    }
                }
            } catch (SQLiteException e) {
                Log.e(TAG, "Could not load photo from database", e);
            } finally {
                if (c != null) {
                    c.close();
                }
            }
            return bitmap;
        }

        /**
         * Remove any bitmap associated with the given appWidgetId.
         */
        public void deletePhoto(int appWidgetId) {
            try {
                SQLiteDatabase db = getWritableDatabase();
                String whereClause = String.format("%s=%d", FIELD_APPWIDGET_ID,
                                                   appWidgetId);
                db.delete(TABLE_PHOTOS, whereClause, null);
            } catch (SQLiteException e) {
                Log.e(TAG, "Could not delete photo from database", e);
            }
        }
    }

}