How to add CardView attributes to app theme?

Question

My question is similar to \"How to put a CardView attribute in a style\", but I need to go deeper.

I\'m using AppCompat theme, and my styles looks like

Answer 1

public View(Context context, AttributeSet attrs, int defStyleAttr)

@param defStyleAttr An attribute in the current theme that contains a reference to a style resource that supplies default values for the view. Can be 0 to not look for defaults.

So you have to do

attrs.xml

<attr name="myCardViewStyle"/>

styles.xml

<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
    <item name="myCardViewStyle">@style/CustomCardView</item>
</style>

<style name="CustomCardView" parent="CardView">
    <item name="cardBackgroundColor">@android:color/holo_red_dark</item>
</style>

MyCardView.java

public MyCardView(Context context, AttributeSet attrs) {
    this(context, attrs, R.attr.myCardViewStyle);
}

public MyCardView(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
}

That's it.