CardView shadow not appearing in Lollipop after obfuscate with proguard

Question

My CardView's shadows have disappeared on Lollipop devices after applying Proguard. I haven't defined any rule to protect this library, because I haven't read it was necessary at all.

I attach you a couple of screenshots, first without running proguard, and secon after running it.

Screenshot without proguard

Screenshot with proguard

And this is my xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
            xmlns:app="http://schemas.android.com/apk/res-auto"
            xmlns:tools="http://schemas.android.com/tools"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical"
            android:paddingLeft="@dimen/activity_horizontal_margin"
            android:paddingRight="@dimen/activity_horizontal_margin"
            android:paddingTop="@dimen/activity_vertical_margin"
            android:paddingBottom="@dimen/activity_vertical_margin"
            tools:context=".MainActivity">

    <android.support.v7.widget.CardView
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        android:layout_margin="4dp"
        app:contentPadding="10dp"
        app:cardUseCompatPadding="true">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Text 1"/>
    </android.support.v7.widget.CardView>

    <android.support.v7.widget.CardView
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        android:layout_margin="4dp"
        app:contentPadding="10dp"
        app:cardUseCompatPadding="false">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Text 2"/>
    </android.support.v7.widget.CardView>

</LinearLayout>

Activity only sets the xml as content and does nothing more. As you can see, I'm using the two possibilities of cardUseCompatPadding, but it doesn't solve the issue as it's defined in this thread.

Does anybody know why proguard is breaking my shadows?

Answer 1

After some diving in the library packages, I wrote a rule that protected everything at android.support.** and now I'm finally protecting just android.support.v7.widget.RoundRectDrawable.

So if you are having troubles with this, just add the next rule at your proguard config:

-keep class android.support.v7.widget.RoundRectDrawable { *; }

Answer 2

FYI, there are some good online collections of the Proguard rules required for each library, e.g. https://github.com/krschultz/android-proguard-snippets/

It looks like your Proguard rule has already been absorbed into that project, and it links back to this Stackoverflow question. :-)
https://github.com/krschultz/android-proguard-snippets/blob/master/libraries/proguard-support-v7-cardview.pro