Wcast is an open-source (MIT license) Android app that lets you search Wikipedia, read a clutter-free version of any article, and have it read aloud — the whole article or a single section at a time — using the Android text-to-speech service. That service can be either the default one that ships with your device, or can be replaced to use other TTS services that allow use of other models.
I use Marmelade-TTS https://github.com/maxwhipw/marmalade-tts-android using PocketTTS for a high-quality, offline TTS engine. Supertonic TTS
by Brahmadeo (in the App store) is also open source and good.
Articles can be manually bookmarked, or are bookmarked when you first start playing them. With bookmarked articles, the app saves your location where you were listening, and it also keeps an offline copy so that if you go offline, you can still listen to them using an offline TTS engine.
Listen to Wikipedia articles using the Android TTS service