Is it possible to get the amount of free memory on an Android device (not on the SD CARD) via the Android SDK?
If so, how?
this post might fit well to your question.
also check this thread. there is so much info here on SO.
googled a bit and here is the solution (found at android git)
File path = Environment.getDataDirectory();
StatFs stat = new StatFs(path.getPath());
long blockSize = stat.getBlockSize();
long availableBlocks = stat.getAvailableBlocks();
return Formatter.formatFileSize(this, availableBlocks * blockSize);