There are a few options for sparkling sweet cider in bottles. YMMV, but none of them are really ideal to me.
First, you can backsweeten with a non-nutritive sweetener like sucralose, aspartame, saccharin or erythritol before bottling. These won't ferment and you'll be left with a "diet soda" version of your cider.
Second, if you keg, you can stabilize and backsweeten the cider, force carbonate, then bottle. Most people who are bottling don't necessarily have this option, though.
DISCLAIMER: I have never done the following and don't necessarily recommend it. There are inherent risks of bottle bombs if not done properly. Still, I have read successful reports of others using this method.
Third, you can bottle at your desired sweetness, allow the bottles to hit the proper carbonation level, then pasteurize in a water bath. You would either monitor fermentation and bottle when it is at the desired sweetness level, or let the cider ferment dry and backsweeten with sugar at packaging. You will need to test bottles intermittently to determine when they hit the proper carbonation level. You then pasteurize the remaining bottles in a water bath to kill the yeast and arrest fermentation. I don't have the specifics off the top of my head of how to set up and perform the actual pasteurization, but the information is out there waiting to be Googled.