findViewById is giving me an ulcer

I'm trying to make a login page but the error message that i get is that there's no value passed for parameter "ID" what ever that means.

Here's the code for LoginActivity.kt:

override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_login)

        val username = findViewById<"username">(R.id.username)
        val password = findViewById<"password">(R.id.password)
        val loginButton = findViewById<"login_button">(R.id.login_button)

        loginButton.setOnClickListener {
            val username = username.text.toString()
            val password = password.text.toString()

            if (username == "lukejjones" && password == "test123") {
                Toast.makeText(this, "Access Granted", Toast.LENGTH_SHORT).show()
            } else {
                Toast.makeText(this, "Access Denied!", Toast.LENGTH_SHORT).show()
            }
        }

Here is the activity_login.xml code related to this:

EditText
            android:id="@+id/username"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:ems="10"
            android:inputType="textPersonName"
            android:padding="20dp"
            android:hint="@+string/Username" />

        <EditText
            android:id="@+id/password"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:ems="10"
            android:inputType="textPassword"
            android:padding="20dp"
            android:hint="@+string/Password" />

        <Button
            android:id="@+id/login_button"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="20dp"
            android:background="@color/black"
            android:text="Login"
            android:textColor="@color/white"
            android:onClick="handleLoginClick"
            />

The thing that goes between the angle brackets is the type of View you are requesting it to look for. It has to be the concrete class (or a superclass) of the View. For example:

val username = findViewById<EditText>(R.id.username)

Alternatively, you can write it like:

val username: EditText = findViewById(R.id.username)

I recommend you read these two pages of the Java documentation, because you need a basic understanding of generics to be able to do much of anything in Kotlin. The Kotlin documentation doesn't cover this for some reason:

• Why Use Generics? But with this one, be aware that their example without generics, where they have to cast, cannot exist in Kotlin because Kotlin enforces generics (no raw types). But it still illustrates why generics are used in the first place.
• Generic Types

Beyond those two pages, it starts to get more into Java-specific stuff so maybe don't confuse yourself by reading those for now. When you're more comfortable with the concept, read the Kotlin documentation on generics and variance.