The purpose of this document is to give anyone who reads it a quick overview of both the current state and the direction of the code. The community should try and update this document as the code evolves.
- App originally built in Java for Android 1.0/T-Mobile G1
- Written at Google by graduate student interns and then University of Washington
- Designed as a survey application backed by JavaRosa communicating with OpenRosa servers
- Many different contributors/styles/eras over 10 year lifetime
- App wasn't built with a TDD workflow or with automated testing
- Lots of work in the last two years to add more tests and clean up code using coverage measurement and static checks
- App has mixture of unit tests (JUnit), Robolectric tests (Junit + Robolectric) and Espresso tests but coverage is far from complete
- Test style, reasoning and layering is inconsistent
- App still written in Java with min API at 16 so basically targeting Java 7 source
- UI has is "iconic" (old) but with a lot of inconsistencies and quirks and is best adapted to small screens
- A lot of code lives in between one "god" Activity (FormEntryActivity) and a process singleton (FormController)
- Core form entry flow uses custom side-to-side swipe view (in FormEntryActivity made up of ODKView)
- Async/reactivity handled with a mixture of callbacks, LiveData and Rx
- App stores data in flat files indexed in SQLite
- Preferences for the app use Android's Preferences abstraction (for UI also)
- Material Components styles are used in some places but app still uses AppCompat theme
- Dagger is used to inject "black box" objects such as Activity and in some other places but isn't set up in a particularly advanced way
- Http is handled using OkHttp3 and https client abstractions are generally wrapped in Android's AsyncTask (and some Rx)
- Geo activities use three engines (Mapbox, osmdroid, Google Maps) depending on the selected basemap even though Mapbox could do everything osmdroid does
- Code goes through static analysis using CheckStyle, PMD, SpotBugs and Android Lint
- Trying to adopt Material Design's language to make design decisions and conversations easier in the absence of designers and to make the UI more consistent for enumerators (“Typography rework” discussion)
- Moving non UI testing away from Espresso to cut down on long test startup times
- Slowly moving responsibilities out of FormEntryActivity
- Talk of moving to Kotlin but not real plans as of yet (“Using Kotlin for ODK Android apps” discussion)
- General effort to increase test coverage and quality while working on anything and pushing more for tests in PR review