how to select from resources randomly (R.drawable.xxxx)

Question

I want to display a random image from the bunch of images i have stored in res/drawable.

The only technique that I know is to access a particular image if you know its r

Answer 1

You can also access resources by name, which may be a viable approach to solving your problem if you know the names of the resources or can derive them according to some pre-defined naming scheme.

You have to map the name to the identifier using the getIdentifier method of the Resources class.

String name = "resource" + rng.nextInt(count);
int resource = getResources().getIdentifier(name, "drawable", "com.package");

The documentation for this method says:

Note: use of this function is discouraged. It is much more efficient to retrieve resources by identifier than by name.

This is true but need not be a problem if you are doing it in code that isn't performance sensitive.

Alternatively, if you don't mind listing the resources in XML, you could create a typed array that you can then randomly select from.

Answer 2

The items in res/drawable are enumerated in the R.drawable class at compile time. You could probably use reflection to get a list of the members of that class, and then select from that list randomly.