TextContrastCheck not handling TextInputLayout.boxStrokeColor correctly

[jozuasijsling-ing]

A false positive warning by TextContrastCheck is observed when using TextInputLayout from com.google.android.material:material. The check treats box stroke color as a foreground color. By default the box stroke color is transluscent, making it likely to trigger the warning.

Reproduction

Given a blank project from Android Studio's Empty Activity template and the following layout:

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <com.google.android.material.textfield.TextInputLayout
        android:padding="24dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Hello World!">

        <com.google.android.material.textfield.TextInputEditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:singleLine="true" />

    </com.google.android.material.textfield.TextInputLayout>

</FrameLayout>

A warning is produced with the following output:

📝 accessibility-test-framework 4.1.1

AccessibilityViewCheckResult check=AccessibilityHierarchyCheckResult WARNING TextContrastCheck 11 [ViewHierarchyElement class=com.google.android.material.textfield.TextInputEditText bounds=Rect(0, 96 - 1080, 423)] {KEY_BACKGROUND_COLOR=-67585, KEY_CONTRAST_RATIO=4.33, KEY_FOREGROUND_COLOR=-8817538, KEY_IS_LARGE_TEXT=false, KEY_REQUIRED_CONTRAST_RATIO=4.5} num_answers:0 view=com.google.android.material.textfield.TextInputEditText{2f293a2 VFED..CL. ........ 0,0-936,167}

📝 Accessibility Scanner 2.4.1.58312255

Accessibility Scanner result

Share text

The following is a list of opportunities to improve the accessibility of My Application. Each item corresponds to an outlined area on the attached screenshot. Contrast tekst [72,184][1008,351] Overweeg de contrastverhouding tussen de voorgrond en achtergrond van deze afbeeldingstekst te verhogen. De contrastverhouding van de itemtekst is 4,33. Deze verhouding is gebaseerd op de geschatte voorgrondkleur #79747E en de geschatte achtergrondkleur #FEF7FF. Overweeg de contrastverhouding van de itemtekst te verhogen naar 4,50 of hoger.

^*For some reason the share text mixes English and Dutch? 🙈 Out of scope.

Negative case

Overriding the default box stroke color with a high contrast color, the warning disappears.

Layout	Accessibility Scanner result