Which to use? Null v Empty

On first use of my app, I want to direct user to ScnIntro, on subsequent uses I want to direct user to ScnBuy. Obviously on first use no data has been input, so is non-existant. Do I use if value is null then do, or, if value is empty? Maybe it is too simple for me, but here are my blocks…


Check it


Yes, I did it your way and it worked. However another problem has surfaced. On the next page a user has to enter a phone number, and that is saved. Using a similar technique, I check that the number is saved, and call/put it in a label on another page.

I then have to force stop the live app to go back to the first page to check everything has worked, and the phone number is not there. I downloaded an apk and installed it, all works well and number is resaved, but on next start, it is not there…


To start, try to make everything easier. Create an application in which a Local Storage is stored some value. Then restart the app and try to retrieve the stored value from the LocalStorade. If that works, then the problem with your algorithm.