如何对自定义视图使用视图绑定

To use the view binding, you need to use the generated binding class not the LayoutInflater, for example, if the layout name is result_profile.xml then you need to use ResultProfileBinding as:

class CustomView @kotlin.jvm.JvmOverloads constructor(
context: Context,
attrs: AttributeSet? = null,
defStyleAttr: Int = 0
) : FrameLayout(context, attrs, defStyleAttr) {


private lateinit var binding: ResultProfileBinding


init { // inflate binding and add as view
binding = ResultProfileBinding.inflate(LayoutInflater.from(context))
addView(binding.root)
}


}

1. Auto generated class : result_profile.xml -> ResultProfileBinding(name of layout, appended with Binding )

2. Inflate the binding

   ResultProfileBinding.inflate(LayoutInflater.from(context))
   

3. Use addView to add the view in the hierarchy as:

   addView(binding.root)
   

Note: If you are extending from ConstraintLayout(is the parent class) then use constraint set

If you are trying to use View Binding with the root view, this is working for me:

class CustomView @JvmOverloads constructor(
context: Context,
attrs: AttributeSet? = null,
defStyleAttr: Int = 0
) : ConstraintLayout(context, attrs, defStyleAttr) {


private lateinit var binding: CustomViewBinding


override fun onFinishInflate() {
super.onFinishInflate()
binding = CustomViewBinding.bind(this)
}
}

Just inform the root, and whether you want to attach to it

init { // inflate binding and add as view
binding = ResultProfileBinding.inflate(LayoutInflater.from(context), this)
}

or

init { // inflate binding and add as view
binding = ResultProfileBinding.inflate(LayoutInflater.from(context), this, true)
}

which inflate method to use will depend on the root layout type in xml.

This is the simplest kotlin answer I can think of. It's a custom view that just wraps a single TextView and provides an update(s:String) function to update the text.

<!-- view_stub.xml -->
<layout xmlns:android="http://schemas.android.com/apk/res/android">
<TextView android:id="@+id/myTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</layout>


// StubView.kt
class StubView @JvmOverloads constructor(
context: Context,
attrs: AttributeSet? = null,
defStyleAttr: Int = 0
) : FrameLayout(context,attrs,defStyleAttr) {


val binding = ViewStubBinding.inflate(context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater)
.also { addView(it.root) }


fun update(updatedText: String) {
binding.myTextView.text = updatedText
}
}

The two things I like about this answer are:

1. binding is a val instead of a var. I try to limit the number of vars as much as possible.
2. The addView is closely associated with the val binding using the also {} scope function instead of an init {} clause, making the instantiation of the View feel much more declarative.

One could argue that the addView() is really a side effect and should be in the init {} section so that it is separate from the declaration of the binding val. I would argue the opposite -- declaring a val then feeding it to a section of code that needs it does not feel like a side effect to me.

You can initialize the view binding property right away

private val binding = CustomViewBinding.inflate(LayoutInflater.from(context), this)