Kotlin databinding does not work and I dont know why

Question

I am new to Android development and have been working through an Android development course online. The last lesson taught me how to use fragments. I was able to follow along with the lesson using the provided framework project file. However when I tried to implement the principles in my own project to practice the data binding wouldn't work. There are two errors. The last import gives the error: "unresolved reference: databinding", and then another error is "unresolved reference: FragmentLoginBinding". I have spent the last 5 hours combing through forum posts and documentation but I cannot find my error. Any help would be greatly appreciated thank you.

*Edit: There is no databinding file in my generated java project file

My code is as follows: fragment_login.kt:

package com.example.project2019
import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.databinding.DataBindingUtil
import com.example.project2019.databinding.FragmentLoginBinding

class fragment_login : Fragment() {
    override fun onCreateView(
    inflater: LayoutInflater, container: ViewGroup?,
    savedInstanceState: Bundle?
    ): View? {
    val binding = DataBindingUtil.inflate<FragmentLoginBinding>(inflater,R.layout.fragment_login,container,false)
    return binding.root
    }
}

fragment_login.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:layout_gravity="center_vertical"
        tools:context="com.example.project2019.fragment_login">

    <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/hello_blank_fragment"
            android:layout_gravity="center_horizontal"
    />
    <Button
            android:id="@+id/loginbtn"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:text="Log In"
    />
</LinearLayout>

Build.Gradle:

apply plugin: 'com.android.application'

apply plugin: 'kotlin-android'

apply plugin: 'kotlin-kapt'
apply plugin: 'kotlin-android-extensions'

android {
    compileSdkVersion 29
    dataBinding {
        enabled = true
    }
    buildToolsVersion "29.0.1"
    defaultConfig {
        applicationId "com.example.project2019"
        minSdkVersion 19
        targetSdkVersion 29
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'androidx.appcompat:appcompat:1.1.0'
    implementation 'androidx.core:core-ktx:1.1.0'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
    implementation "com.google.android.material:material:$version_material"
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test:runner:1.2.0'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
}

Answer 1

Try adding the following lines to the build.gradle file

buildFeatures {
     viewBinding true
}
dataBinding.enabled=true

Answer 2

You have to enclose your fragment_login.xml with layout to work data binding

<?xml version="1.0" encoding="utf-8"?>
<layout>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
         xmlns:tools="http://schemas.android.com/tools"  
         android:layout_width="match_parent"  
         android:layout_height="match_parent"  
         android:orientation="vertical"  
         android:layout_gravity="center_vertical"  
         tools:context="com.example.project2019.fragment_login">  
        <TextView  
             android:layout_width="wrap_content"  
             android:layout_height="wrap_content"  
             android:text="@string/hello_blank_fragment"  
             android:layout_gravity="center_horizontal" />   
        <Button  
             android:id="@+id/loginbtn"  
             android:layout_width="wrap_content"  
             android:layout_height="wrap_content"  
             android:layout_gravity="center_horizontal"  
             android:text="Log In" />  
    </LinearLayout>  
</layout>