Question

The suggested way of implementing menus in Android is to use XML to define a menu, which works for static menus. I’m currently trying to create a dynamic sub-menu, though, and I’d like to associate unique item ids with each of the items in a submenu so that I can store metadata with them.

There’s an answer here that suggests using an autoincrementing id, but I also have existing item ids being used for other parts of the menu that look like this (in R.java)

public static final int item2=0x7f070002;

I’m sure I can start at id = 1 and then increment, but if the id generation scheme ever changes for R.java, I’m worried I’ll start seeing collisions. Is there a better way of generating these ids? Or do I just need to keep track of the max id, then start incrementing from there?

Answer 1

The “correct” solution would be to traverse the objects that describe the menus to find all of the ids that are in use, then use a different one.

But, if you are prepared to live with a small chance of a problem, you could simply generate your dynamic menu ids using a random number generator. Assuming you have 32 bit ids, the probablility of a single collision menu item colliding is N / 2^32 where N is the number of existing menu ids. If we assume a reasonable value for N, that’s a pretty small number …