What I gather from the article is that you don't need to do anything to reclaim memory, but you can make garbage collection happen quicker and at specific times. What this means to me is that any arrays, Lists, large objects, etc. should be set to null
when you are done with it. Granted, this should be done automatically when you leave a method or a View, but in case you are in a long running loop or staying on a page with lots of data hanging around, you can clean it up a little faster.
The Android Runtime (ART) and Dalvik virtual machine use paging and memory-mapping (mmapping) to manage memory. This means that any memory an app modifies—whether by allocating new objects or touching mmapped pages—remains resident in RAM and cannot be paged out. The only way to release memory from an app is to release object references that the app holds, making the memory available to the garbage collector. That is with one exception: any files mmapped in without modification, such as code, can be paged out of RAM if the system wants to use that memory elsewhere.
https://developer.android.com/topic/performance/memory-overview
You can also check your memory usage to see if that's really the problem. This is linked in the article above, but I thought I'd pop it out so it's easier to notice.
https://developer.android.com/reference/android/app/ActivityManager.html#getMemoryClass()