应用程序打开的文件太多 - Android

I have a method called calcDays() which loops through a database over and over again until a certain condition is met. The problem is that Android studio is telling me that I've run out of files. I realize that I'm opening databases and not closing them, which is why I have the error. However, I cannot seem to fix this error.I have a method called calcDays() which loops t