AlertDialog vs AlertDialog.Builder

Question

Why would one use the AlertDialog.Builder class rather than the methods directly available to AlertDialog, For example, why use AlertDialog.Builder.setCancellable rather than AlertDialog.setCancellable? Surely this is a case of redundancy?

Answer 1

Because AlertDialog.setCancellable returns void and AlertDialog.Builder.setCancellable returns an AlertDialog.Builder.

This means that the builder allows you to chain a bunch of settings with a little less verbosity. It's just a convenience class

Answer 2

AlertDialog allows you to show a dialog above your activity/fragment. It is usually used for prompting user for interaction including few buttons or notifying for something.

AlertDialog.Builder is an inner static class of AlertDialog which allows you to quickly setup a dialog with its handy methods. Its just like a helper class to AlertDialog. It is used for calling methods in a chain.