At the beginning of this year, we released offline read-only beta for Android devices. Today we rolled it out to the general public, so you are now able to read your tasks on your Android device while offline.
We’re still planning a native Android app. We’re sorry it’s taking longer than you are expecting.mo lohaus commented
Great that you are doing a mobile website with local caching not a device-specific app: think cross-platform! Plan to use with both an iPhone and Chromebook.