passive voice - I am being hungry

We are being robbed.

Being means right now happening.

Can I say "I am being hungry"?

Answer

In English, adjectives can't form predicates on their own. We need a verb, so we add the copular verb be, which links the adjective to the subject:

I am hungry.

Adjectival predicates like be hungry are stative. In other words, they express a state rather than an event. In English, stative predicates generally appear in the simple present; they don't appear in the progressive be V-ing construction, because the progressive requires a dynamic predicate.

Most so-called stative verbs can actually have some dynamic meaning added to them, so it's usually possible to use them in the progressive, but these progressive uses are fairly limited. We wouldn't usually say:

I am being hungry.

When is adding dynamic meaning possible? That depends on the verb. In the case of be forming an adjectival predicate, the progressive is seems to add an element of volitionality to the predicate:

My little brother is annoying.　←　stative
My little brother is being annoying.　←　dynamic, volitional

The former example expresses a general trait about a little brother, while the latter expresses something about the little brother's behavior. This is possible because little brothers are capable of volition – that is, capable of doing something annoying on purpose. Compare the following:

The river is noisy.　←　stative
^#The river is being noisy.　←　dynamic, but doesn't make sense in most contexts

Rivers are not capable of volition, but the progressive marks the river as volitional, so this predicate doesn't really make sense; a volitional predicate cannot predicate on a non-volitional subject. The only way to make sense of this sentence is to interpret the river as an entity capable of volition, for example in a fantasy scenario with a living river, or by anthropomorphizing the river as a figure of speech.

Now what about be hungry? That predicate is a lot harder to add dynamic meaning to! Adjectival predicates can be cast in the progressive if they're volitional, but be hungry is usually non-volitional, so you'd have to come up with an interpretation that adds volition to it. A native speaker might be able to figure out a way to reconcile the meaning, but it's a bit of a stretch, and normally people wouldn't say this sort of thing.

Now let's take a look at your other example:

We are being robbed.

In this example we find two different bes. The first is the progressive auxiliary be, in the progressive be V-ing construction; the second is the passive auxiliary be, in the passive be V-ed construction.

However, this is not an adjectival predicate with copular be. In fact, the passive be robbed is dynamic in meaning, expressing an event rather than a state, and so it most naturally appears in the progressive be V-ing construction rather than the simple present.

In other words, your two examples are very different, and be plays different roles in them.