How to dump views definition in one schema?

Good morning,

Can pg_dump or other command could dump all views definition in one schema.

I was trying to alter column types for several tables, and I have very 
complicated view dependencies.

What I try to do is:
(1). Back all views def
(2). alter columns
(3). re-create views from (1)

I'd like to know how to dump all views in one schema?

Thanks,

--
Lu Ying