Why is Samsung Galaxy S6 (Lollipop) allocating 4 times the memory of older devices for bitmaps
I just started testing my game app on a new Samsung Galaxy S6. It kept crashing with out of memory errors in the log. My app normally uses about 215M and worked fine with the Galaxy S4 mini, Galaxy Tab S3, and Galaxy Tab S4, which have heaps of 256+M, 512+M and 512+M respectively. The Galaxy S6 has a heap of 536M. After cutting down my bitmap sizes to where I could get the Galaxy S6 to run the app, I got the following on the device monitor for heap use of the various devices.
Galaxy S4 mini, Galaxy Tab S3, and Galaxy Tab S4:
Galaxy S6 (Lollipop):
Why does the newer device use 4 times the heap of the other devices?
It turns out the issue was something being done on the device end, not mentioned in the documentation on supporting different screen sizes here: http://developer.android.com/training/multiscreen/screensizes.html. According to an insightful article by Gokhan Arik, 'Android background image high memory usage issue' at http://gokhanarik.com/android-background-image-high-memory-usage-issue/, referencing a CommonsWare answer to a question similar to mine here: Why does my 160kb app background become 49 MB at run time?, high density devices will resize images stored in a generic 'drawable' folder to a much greater size to match the higher screen resolution, by 4x in my case.
The simple solution was to put all my bitmaps (many several hundred KB in size) into a folder named 'drawable-nodpi', and deleting the old 'drawable' folder. I wish I knew about this issue before I could finally afford a density 3 device to test on.
One drawback to this I recently found is that Google Play will no longer consider your device 'designed for tablets' when you don't have several drawable folders for different screen densities. So incredibly, you may have to create empty ones to not lose this designation.