View Binding got released with v3.6.
Docs: https://developer.android.com/topic/libraries/view-binding
My question is, does anyone know how to use view binding with included layouts?
Given Layout that includes another Layout
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<include
android:id="@+id/my_header"
layout="@layout/item_header"
android:layout_width="match_parent"
android:layout_height="100dp" />
</LinearLayout>
I am trying to reference items inside of the item_header layout.
binder.my_header (<-- this just returns back the view)
binder.root (<-- this just returns back the root view)
Even if I add an id to the root of the item_header, such as id="@+id/parent_id" and try to reference that, I receive null pointer exceptions
binder.parentId (<-- I have access to views inside of the item_header, however, I receive exceptions. Says that "parentId" cannot be found)
How to reference the layout, item_header
?
Let's suppose that the layout in your question is activity_main.xml
. The generated view binding class for it is ActivityMainBinding
. Similarly, for item_header.xml
, the generated view binding is ItemHeaderBinding
.
If we pretend that item_header.xml
has a TextView
named @+id/foo
, then you wind up with this chunk of Kotlin:
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
val mainBinding = ActivityMainBinding.inflate(layoutInflater)
setContentView(mainBinding.root)
mainBinding.myHeader.foo.text = "this is a test"
}
}
So, the ActivityMainBinding
object should have a property with the android:id
that you gave to the <include>
— myHeader
in this case. That should be an ItemHeaderBinding
, as view binding appears to set up the nested binding object for the <include>
. Since myHeader
is an ItemHeaderBinding
, you can then reference widgets on it just as you would if you directly inflated ItemHeaderBinding
yourself.
Note that view binding appears to convert lower_snake_case
into lowerCamelCase
, so the my_header
ID turns into myHeader
in terms of the generated code.