Why does the generated view binding .inflate() method requires root parameter?

Question

I was following the example from the documentation on a personal project.

I have a layout called activity_main.xml, for which an ActivityMainBinding class is generated. When I call ActivityMainBinding.inflate(layoutInflater), I get an error saying that the method requires the "root" parameter of type ViewGroup.

Why isn't the method with only one argument (the inflater) available?

I've tried cleaning and rebuilding the project.

build.gradle (app)

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'

android {
    compileSdkVersion 29
    buildToolsVersion "29.0.3"

    defaultConfig {
        applicationId "com.example.teddy"
        minSdkVersion 22
        targetSdkVersion 29
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }

    kotlinOptions {
        jvmTarget = JavaVersion.VERSION_1_8.toString()
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }

    viewBinding {
        enabled = true
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'androidx.appcompat:appcompat:1.1.0'
    implementation 'androidx.core:core-ktx:1.2.0'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
    implementation 'androidx.navigation:navigation-fragment-ktx:2.2.2'
    implementation 'androidx.navigation:navigation-ui-ktx:2.2.2'
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <androidx.drawerlayout.widget.DrawerLayout
        android:id="@+id/drawer_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true">

        <fragment
            android:id="@+id/nav_host_fragment"
            android:name="androidx.navigation.fragment.NavHostFragment"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:defaultNavHost="true"
            app:navGraph="@navigation/navigation" />

        <com.google.android.material.navigation.NavigationView
            android:id="@+id/navView"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_gravity="start"
            app:headerLayout="@layout/nav_header"
            app:menu="@menu/navdrawer" />
    </androidx.drawerlayout.widget.DrawerLayout>
</merge>

MainActivity.kt

package com.example.teddy

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.drawerlayout.widget.DrawerLayout
import androidx.navigation.findNavController
import androidx.navigation.ui.AppBarConfiguration
import androidx.navigation.ui.setupWithNavController
import com.example.teddy.databinding.ActivityMainBinding
import com.google.android.material.navigation.NavigationView

class MainActivity : AppCompatActivity() {
    private lateinit var drawerLayout: DrawerLayout
    private lateinit var binding: ActivityMainBinding

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

        binding = ActivityMainBinding.inflate(layoutInflater)
        val view = binding.root
        setContentView(view)

        val navController = this.findNavController(R.id.nav_host_fragment)
        drawerLayout = binding.drawerLayout

        val appBarConfiguration = AppBarConfiguration(navController.graph, drawerLayout)
        findViewById<NavigationView>(R.id.navView)
            .setupWithNavController(navController)
    }
}

Does anyone know what I am missing?

EDIT The exact error from the failed build output:

No value passed for parameter 'parent’

The tooltip on the underlined error in the code says

No value passed for parameter 'root'

Answer 1

I might have solved the problem by changing the merge tag by a layout tag in the activity_main.xml. Not really sure why I had a merge there... Probably legacy of a template.

Thank you for looking into it !

Answer 2

You should use the setContentView method in DataBindingUtil.

Change this

    binding = ActivityMainBinding.inflate(layoutInflater)
    val view = binding.root
    setContentView(view)

to this

    binding = DataBindingUtil.setContentView(this, R.layout.activity_main)