Android Studio app doing double + double or double + int

so I have an app where I wanna make people able to type fx 1.1 in the first box and 2 in the second box soi will plus the two boxes and it also having support for 1 decimal but it gives wrong answers and only works the first time (see video) youtu.be/vawL_bFBV-k

here is the code pastebin.com/raw/nwis8JUZ

I have been trying to fix it for the last few months