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url if (cursor.moveToFirst()) { path = cursor.getString(cursor.getColumnIndex(Media.DATA)); } cursor.close(); return path; }

未完，待续