My question may look naive but I do not know how to formulate it more correctly. The problem is that I create and use large simple type arrays in my application. And I get errors like:
ERROR/dalvikvm-heap(1763): Out of memory on a 7907344-byte allocation.
Yes, it’s big enough but task management tools claim that my application is using only 30MB of memory, while other at the same time use 50MB and even 110MB (have seen once) and there is still 190MB of free memory in the system (not system applications, just other ordinary applications I have installed). If all applications are provided with the same heap size at startup how can they grow so big?
The maximum heap size of an Android application will depend on the device it is running on. For early devices the maximum heap size was 16MB but for some later devices it can be 24MB or possibly even 32MB.
This is a property of the Dalvik VM on each device and is not something you can change (without rebuilding Android from source).
You can query the “per-application memory class” with
ActivityManager.getMemoryClass()which seems to be a figure which is not entirely unrelated to the Heap Size.Applications can use memory which isn’t on the heap but 100+MB seems like a surprisingly large amount.
If you want to find out about analysing memory usage on Android you can’t do better than this Stack Overflow answer by Dianne Hackborn, who is one of the Android developers at Google. In short it says analysing memory usage is very difficult and you should take any figures you have with a pinch of salt.