Override Android-L CardView state_pressed for Older versions of Android

Question

In the latest Android SDK we now have the new CardView, I have replaced my old CustomCardView with the new version, but when running with this on older versions of Android I see that the state_pressed & state_focused are ugly squares which show up above the CardView...

does anyone know how I could emulate the following in the new CardView but only when using older versions of Android?

<selector xmlns:android="http://schemas.android.com/apk/res/android"
    android:enterFadeDuration="150"
    android:exitFadeDuration="150" >

    <item android:state_pressed="true"
          android:drawable="@drawable/card_on_press"/>
    <item android:state_focused="true" android:state_enabled="true"
          android:drawable="@drawable/card_on_focus"/>
    <item android:state_enabled="true"
          android:drawable="@drawable/card_default"/>
    <item android:state_enabled="false"
          android:drawable="@drawable/card_on_press"/>

</selector>

And for those of you interested here is the CardView that I am using now:

<android.support.v7.widget.CardView
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    android:id="@+id/CardView"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginLeft="10dp"
    android:layout_marginRight="10dp"
    android:layout_marginTop="10dp"
    android:foreground="?android:attr/selectableItemBackground"
    android:onClick="RunSomeMethod"
    card_view:cardCornerRadius="4dp"
    android:focusable="true"
    android:elevation="2dp">

    <LinearLayout
        android:id="@+id/LinearLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:focusable="false"
        android:visibility="visible">

    </LinearLayout>
</android.support.v7.widget.CardView>

Answer 1

Here is the code that I used in the card_on_press.xml file which is stored in the drawable folder of the project:

<item>
    <shape>
        <padding
            android:bottom="0dp"
            android:left="0dp"
            android:right="0dp"
            android:top="0dp" />
        <solid android:color="@color/transparent" />
    </shape>
</item>

<item>
    <shape>
        <padding
            android:bottom="0dp"
            android:left="0dp"
            android:right="0dp"
            android:top="0dp" />
        <solid android:color="@color/card_shadow_1_on_press" />
        <corners android:radius="8dp" />
    </shape>
</item>
<item>
    <shape>
        <padding
            android:bottom="0dp"
            android:left="0dp"
            android:right="0dp"
            android:top="0dp" />
        <solid android:color="@color/card_shadow_2_on_press" />
        <corners android:radius="8dp" />
    </shape>
</item>
<!-- Background -->
<item>
    <shape>
        <solid android:color="@color/card_background_on_press" />
        <corners android:radius="8dp" />
    </shape>
</item>

Answer 2

Maybe the library has been updated but when I use the following it looks fine on older versions of Android.

You can use the 'CardView.Dark' and CardView.Light' (will auto-generate with the card support library)

In your values/styles.xml

<style name="CardViewStyle.Light" parent="CardView.Light">
    <item name="android:foreground">?android:attr/selectableItemBackground</item>
</style>

<style name="CardViewStyle.Dark" parent="CardView.Dark">
    <item name="android:foreground">?android:attr/selectableItemBackground</item>
</style>

---

Layouts for CardView

Create two layouts, one for dark and one for light. They will include the card views like this:

<android.support.v7.widget.CardView
        android:id="@+id/my_card_view"
        style="@style/CardViewStyle.Light"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:orientation="vertical"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginBottom="8dp"
        app:cardCornerRadius="2dp"
        android:elevation="2dp">

    ... other layout stuff ...

</android.support.v7.widget.CardView>

---

<android.support.v7.widget.CardView
        android:id="@+id/my_card_view"
        style="@style/CardViewStyle.Dark"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:orientation="vertical"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginBottom="8dp"
        app:cardCornerRadius="2dp"
        android:elevation="2dp">

    ... other layout stuff ...

</android.support.v7.widget.CardView>

Take note to switching the style in each CardView.

Other customizations

If you want to customize the color rather than just having black or white, you can use the following:

To get the CardView drawable you can use:

View cardView = findViewById(R.id.my_card_view);
Drawable cardViewDrawable cardView.getBackground();
convertIcon(setViewBackground(cardView, cardViewDrawable));

---

My 'convertIcon' is simply the following:

/**
 *
 * @param drawable e.g. "getResources().getDrawable(R.drawable.my_drawable)"
 * @param tint e.g. "Color.parseColor(lightTitlebarFg)"
 * @return Drawable
 *
 */
public static Drawable convertIcon(Drawable drawable, int tint) {
    ColorFilter filter = new PorterDuffColorFilter(tint, PorterDuff.Mode.SRC_ATOP);
    drawable.setColorFilter(filter);
    return drawable;
}

My 'setViewBackground' is simply the following:

@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
@SuppressWarnings("deprecation")
public static void setViewBackground(View view, Drawable drawable){
    if (UIUtils.isJB()) {
        view.setBackground(drawable);
    } else {
        view.setBackgroundDrawable(drawable);
    }
}

StateListDrawable

If you want to create a StateListDrawable programmatically can use the following:

StateListDrawable states = new StateListDrawable();
states.addState(new int[] { android.R.attr.state_focused }, focusedDrawable);
states.addState(new int[] { android.R.attr.state_activated }, activatedDrawable);
states.addState(new int[] { android.R.attr.state_enabled }, defaultDrawable);
states.addState(new int[] {}, defaultDrawable);