how to call fun from another class in xml OnClick attribute

i need to run testPrint from NavbarActions.kt

class NavbarActions {

    fun testPrint(view: View) {
        Log.i("check", "success")
    }
    
}

from activity_navbar.xml without using NavbarActivity.kt in TW

<TextView
    android:onClick="?????"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:text="TEST"
/>

You can achieve this by using a custom binding adapter. Here's how you can do it:

1. Create a file named BindingAdapters.kt (if it doesn't exist) in your project's source directory and add the following code:

import android.view.View
import androidx.databinding.BindingAdapter

@BindingAdapter("onClickTestPrint")
fun View.setTestPrintClickListener(navbarActions: NavbarActions) {
    setOnClickListener { navbarActions.testPrint(this) }
}

2. In your activity_navbar.xml, add the onClickTestPrint attribute to the TextView:

<TextView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:text="TEST"
    app:onClickTestPrint="@{navbarActions}" />

Note that you need to replace @{navbarActions} with the actual instance of NavbarActions that you want to use.

3. Finally, when you set up the data binding in your activity (e.g., MainActivity.kt), make sure to set the navbarActions variable with an instance of NavbarActions:

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.databinding.DataBindingUtil
import com.yourpackage.databinding.ActivityNavbarBinding

class MainActivity : AppCompatActivity() {

    private lateinit var binding: ActivityNavbarBinding

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        binding = DataBindingUtil.setContentView(this, R.layout.activity_navbar)
        binding.navbarActions = NavbarActions()
    }
}

Make sure to replace com.yourpackage with the actual package name of your project.

Now, when the "TEST" TextView is clicked, it will directly call the testPrint function from the NavbarActions instance specified in the navbarActions variable in your activity.

You can't. The onClick attribute will only translate to a function in the Activity that it's in. You will need to call the other function from the activity.