Can't set color filter to overflow icon in Toolbar

Question

Why does Kotlin not allow me to apply a color filter to the overflow icon in my Toolbar?

Expression 'colorFilter' of type 'ColorFilter' cannot be invoked as a function. The function 'invoke()' is not found

XML

<?xml version="1.0" encoding="utf-8"?>
<androidx.appcompat.widget.Toolbar
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/my_toolbar"
    android:layout_width="match_parent"
    android:layout_height="?android:attr/actionBarSize"
    android:minHeight="?android:attr/actionBarSize"
    app:contentInsetStartWithNavigation="0dp"
    app:contentInsetStart="0dp">

    <LinearLayout
        android:id="@+id/toolbar_textLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center_vertical"
        android:layout_marginStart="16dp"
        android:orientation="vertical">

        <TextView
            android:id="@+id/toolbar_title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
          style="@android:style/TextAppearance.Material.Widget.ActionBar.Title"/>
    </LinearLayout>
</androidx.appcompat.widget.Toolbar>

Kotlin

    mToolbar.overflowIcon?.colorFilter(Color.RED, PorterDuff.Mode.SRC_ATOP)

    // 
    val myAttr = intArrayOf(R.attr.tintColor)
    val taAttr = this.theme.obtainStyledAttributes(myAttr)
    val colorAttr = taAttr.getColor(0, Color.BLACK)

Answer 1

TL;DR: Change colorFilter() to setColorFilter().

---

There are two setColorFilter() methods on Drawable.

One takes a ColorFilter. That matches a corresponding getColorFilter() method. Kotlin treats those as being syntactically equal to a var named colorFilter. So, if you had a ColorFilter object, you could write:

 mToolbar.overflowIcon?.colorFilter = myReallyCoolColorFilterNoReallyItAddsBlueTintToEverything

The other setColorFilter() call takes the two parameters that you are specifying: the color and the PorterDuff.Mode. However, that method is setColorFilter(), not colorFilter(). So, either switch to setColorFilter() or:

 mToolbar.overflowIcon?.colorFilter = BlendModeColorFilter(Color.RED, BlendMode.SRC_ATOP)

Since you are trying to reference colorFilter, Kotlin assumes that you mean the colorFilter property, and that is not a function type and cannot be called like one.