PrefixTree Performance and Memory Impact
I’ve done some measuring, on my Nexus 7. Using the PrefixTree “string packing” on large forms with many strings is costly, as you can see here:
The getLocalData method, which creates and loads the PrefixTree, takes 20 times as long when the packing is enabled for eIMCI, and 706 times as long for Nigeria Wards.
Not packing the strings requires more space. According to the Android Studio Profiler, the “shallow size” of a PrefixTreeNode is about 32 bytes. Add in a List of references to children, and the character array size, and you have the size of the node. A rough estimate for the not-packed Nigeria Wards PrefixTree, with its root node, and all descendants being immediate children, is 2 MB.