Hi guys. May I know what's the difference between

findViewById()

and

findViewById<>()

?

findViewById<>()

is not valid syntax in Kotlin, are you asking about Java?

I'm writing it in Kotlin.

You cannot write

findViewById<>()

in Kotlin

recyclerView = findViewById(R.id.vibe_recycler_view).apply{}

Not valid

Only something like

findViewById<SomeView>()

recyclerView = findViewById<RecyclerView>(R.id.vibe_recycler_view).apply{}

Valid.

Because findViewById can returns different type

I place

<RecyclerView>

just to tell the compiler i am confirm this

findViewByID

is

RecyclerView

?

Yes, because compiler dont’ know type which you want

My case is

private lateinit var recyclerView: RecyclerView

recyclerView = findViewById<RecyclerView>(R.id.vibe_recycler_view)

but this is not:

val recyclerView = findViewById()

because compiler doesn’t know type that you want, function findViewById is parameterized

I see.

I see you problem

I tried requireViewById also require to pass in explicitly argument.

Works for me

You mean the

.apply

?

no, requireViewById

So it does not matter for me to use

requireViewById

or

findViewById

right?

you can write own extension function

💡 I get it now.

You can write something like this to have requireViewById without passing additional param

fun <T : View> Activity.requireViewById(id: Int) = findViewById<T>(id) ?: error("View with id $id not found")

Let me try it out.