IDE: Android Studio
Build system: Gradle
Programming language: Kotlin
Primary libraries: Jetpack, Realm
- Use DataBinding for displaying simple data. If a more complex expression is required for preparing/formatting the data, set it from code or use a static (
@JvmStatic) utility method in the respective Fragment/Activity/ViewModel/View.
All main content is displayed in fragments that inherit from MainFragment. This base class e.g. handles refresh and sharing actions. Configurations (title, menu items, FAB, etc.) are configured via MainFragment#provideConfig().
Data is managed by so-called repository. They exist as singletons (Kotlin-object) and are invoked to perform any data-manipulating action. Repositories forward requests to a DAO or a storage. DAOs interact with the Realm-database, whereas storages wrap Android's native SharedPreferences.
For an example of Repository + DAO, see the implementation of .models.course.CourseRepository
For an example of Repository + Storage, see the implementation of .models.user.UserRepository
Syncing of data (e.g. to the HPI Schul-Cloud server) is done via sync-methods in the repository. They call a [Job][RequestJob] (inside [.jobs][.jobs]), which itself calls a method of .network.ApiServiceInterface. The retrieved data is then stored in Realm using [Sync][Sync].
For an example of Job + Sync, see the implementation of .jobs.ListUserCoursesJob
Implementing a RecyclerView.Adapter is pretty simple, and we've made it even easier! Just extend BaseAdapter, and most of the boilerplate code is handled for you.
For an example, see the implementation of TopicListAdapter
For displaying HTML-based formatted content, please use either ContentTextView (for unformatted previews up to four lines) or ContentWebView (for longer, formatted content). ContentWebView takes care of loading internal content (using authentication), correct opening of links (external vs internal) and resizes content designed for larger screens.
External links are opened using openUrl, which creates a CustomTab behind the scenes.
If the displayed content should be non-interactive, use PassiveWebView instead. It works the same but doesn't catch any click or scroll events.
For sharing the view of an activity or fragment, just overwrite the property url. That's it! The base classes create a menu item handle the share action, passing the url-String. The current toolbar title is used as the share-Intents subject.
To implement refreshing behaviour in an activity or fragment, simply set the property swipeRefreshLayout to the SwipeRefreshLayout (SRL from now on) instance, and override refresh(). The base classes handle SRL styling, toggle SRL state, add a menu item for refresh and perform the actual refresh.
For an example, see the implementation of CourseListFragment
Indicating a successful action to the user is done by calling showGenericSuccess, passing a string or string resource. This will create a toast.
An error can be shown by calling showGenericError, passing a string or string resource. This will create a toast, and the error message is automagically prefixed with "Error: " for consistency.
If other ways of notifying the user of an error are available, they should generally be preferred. Examples include @style/Content_Text.Empty for empty content, TextView.setError() for inputs, etc.
Showing an indeterminate progress dialog is as simple as wrapping a suspend-function with withProgressDialog, passing a string or string resource shown in the dialog to inform the user.
For an example, see the implementation of FileActivity#loadFile()