CheckBoxPreference & SwitchPreference have no animation on pre-Lollipop

[ferrannp]

As we can read in the README.txt, in order to create a Material looking SwitchPreference we actually use this trick:

<CheckBoxPreference
    android:key="some_key"
    android:title="Hooray!"
    android:widgetLayout="@layout/mp_preference_switch"/>

It works pretty good with just one drawback: There is no animation for pre-Lollipop devices (Switch switches instantly).

There is a post in StackOverflow about it: http://stackoverflow.com/questions/30336635/extending-preference-classes-in-android-lollipop-losing-animation

In the same way, this also happens with a pure CheckBoxPreference:

<CheckBoxPreference
    android:key="some_key"
    android:title="Hooray!" />

There is an opened and forgotten bug about it here: https://code.google.com/p/android/issues/detail?id=85392