android SQLite （Cursor SQLiteDatabase SQLiteOpenHelper ContentValues ContentProvider）总结

一直在零零碎碎的用着SQLite，包括什么Cursor SQLiteDatabase SQLiteOpenHelper ContentValues ContentProvider等等
但是每次回头使用总是觉得有点乱，今天总结一下，献给和我一样的小菜鸟。

先来一个引子：

在android DDMS里面data\data\com.android.providers.media的数据库external-cef1c12.db里面存放了两个table，

其中Media放的是真正地图片，Thumbnails放的是图片的缩略图，缩略图是android系统自动生成的

下面两段代码时读取缩略图和图片

              /*        *
 * 读取缩略图
         */        
         private         ArrayList        <        PhotoItem        >         getPhotosInfo()
 {
 ArrayList        <        PhotoItem        >         photolist         =                 new         ArrayList        <        PhotoItem        >        ();
 Cursor cursor         =         getContentResolver().query(
 Thumbnails.EXTERNAL_CONTENT_URI,         null        ,         null        ,         null        ,         null        );
         //        Thumbnails.EXTERNAL_CONTENT_URI存放的是缩略图的url        
                 if         (cursor.moveToFirst())
 {
         do        
 {
 PhotoItem pi         =                 new         PhotoItem();
 pi.ImageID         =         cursor.getInt(cursor
 .getColumnIndex(Thumbnails.IMAGE_ID));
 pi.photoPath         =         cursor.getString(cursor
 .getColumnIndex(Thumbnails.DATA));
 photolist.add(pi);
 }
         while         (cursor.moveToNext());
 }
 cursor.close();
         return         photolist;
 }

/** * 读取缩略图 */private ArrayList<PhotoItem> getPhotosInfo(){ArrayList<PhotoItem> photolist = new ArrayList<PhotoItem>();Cursor cursor = getContentResolver().query(Thumbnails.EXTERNAL_CONTENT_URI, null, null, null, null);//Thumbnails.EXTERNAL_CONTENT_URI存放的是缩略图的urlif (cursor.moveToFirst()){do{PhotoItem pi = new PhotoItem();pi.ImageID = cursor.getInt(cursor.getColumnIndex(Thumbnails.IMAGE_ID));pi.photoPath = cursor.getString(cursor.getColumnIndex(Thumbnails.DATA));photolist.add(pi);}while (cursor.moveToNext());}cursor.close();return photolist;}

/** * 读取缩略图 */private ArrayList<PhotoItem> getPhotosInfo(){ArrayList<PhotoItem> photolist = new ArrayList<PhotoItem>();Cursor cursor = getContentResolver().query(Thumbnails.EXTERNAL_CONTENT_URI, null, null, null, null);//Thumbnails.EXTERNAL_CONTENT_URI存放的是缩略图的urlif (cursor.moveToFirst()){do{PhotoItem pi = new PhotoItem();pi.ImageID = cursor.getInt(cursor.getColumnIndex(Thumbnails.IMAGE_ID));pi.photoPath = cursor.getString(cursor.getColumnIndex(Thumbnails.DATA));photolist.add(pi);}while (cursor.moveToNext());}cursor.close();return photolist;}

/** * 读取图片 */private String getRealPath(int id){String path = null;Cursor cursor = getContentResolver().query(Media.EXTERNAL_CONTENT_URI,null, Media._ID + " = " + id, null, null);//Media.EXTERNAL_CONTENT_URI存放的是图片的urlif (cursor.moveToFirst()){path = cursor.getString(cursor.getColumnIndex(Media.DATA));}cursor.close();return path;}

未完，待续

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