Q:

change background color on android buttons

I want to have my buttons to have the colors I specified, but otherwise still look and behave like the standard buttons.  So I searched and found this.  I followed the advice given there, but the background color stays the standard grey.  Any Idea where I´m going wrong? 
In my styles.xml I put this:
<style name="AppTheme. Button" parent="Widget. AppCompat. Button. Borderless. Colored">
<item name="android:colorButtonNormal">@color/colorButtonDark</item>
<item name="android:textColor">@color/colorAccent</item>
</style>

My colors are these:
<resources>
[...]
<color name="colorAccent">#ffffff</color>
<color name="colorButtonDark">#300a03</color>
</resources>

And one example Button looks like this:
<Button
        android:text="exampleButton"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:id="@+id/button7" android:layout_marginTop="8dp"
        app:layout_constraintTop_toTopOf="@+id/guideline19" android:layout_marginBottom="8dp"
        app:layout_constraintBottom_toBottomOf="parent" 
        app:layout_constraintStart_toStartOf="@+id/guideline"
        android:layout_marginStart="8dp" app:layout_constraintEnd_toEndOf="parent"
        android:layout_marginEnd="8dp" android:theme="@style/AppTheme. Button"/>

A:

Try to use android.support.v7.widget. AppCompatButton instead of Button in xml. 
<android.support.v7.widget. AppCompatButton
    android:text="exampleButton"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:id="@+id/button7" android:layout_marginTop="8dp"
    app:layout_constraintTop_toTopOf="@+id/guideline19" 
    android:layout_marginBottom="8dp"
    app:layout_constraintBottom_toBottomOf="parent" 
    app:layout_constraintStart_toStartOf="@+id/guideline"
    android:layout_marginStart="8dp" app:layout_constraintEnd_toEndOf="parent"
    android:layout_marginEnd="8dp" android:theme="@style/AppTheme. Button"/>

