Laudate is the most popular free Android app for Catholics.

Laudate is the most comprehensive Catholocism app available on the market. It is multilingual, available in sixteen different languages. The app has a minimalist, intuitive user interface that allows you to easily tab between different aspects of Catholocism. You can also personalize the app to suit your unique needs and practice.

Laudate has many different features that make being a practicing Catholic easy. You can access daily mass readings and the order of mass, as well as Latin mass, the liturgy of hours, the Latin liturgy of hours, the rosary, the Chaplet of Divine Mercy, and several other rosaries and chaplets. There are various prayers available in both the app's native language and Latin. Also included are daily prayers and meditations, along with podcasts of daily readings with associated meditations. The second Vatican documents, papal encyclical letters, and Code of Canon Law are all available for perusal.

You can bookmark prayers and customize your own prayers. There's an Export/Import function for prayers; you can edit prayers on your PC or Mac and then import them to the app. It's easy to track your prayers and your readings using the interface.