The previous code generally started an activity by having the activity
provide a method in a companion object that returns the relevant intent,
possibly taking additional parameters that will be included in the
intent as extras.
E.g., if A wants to start B, B provides the method that returns the
intent that starts B.
This introduces a dependency between A and B.
This is worse if B also wants to start A.
For example, if A is `StatusListActivity` and B is`ViewThreadActivity`.
The user might click a status in `StatusListActivity` to view the
thread, starting `ViewThreadActivity`. But from the thread they might
click a hashtag to view the list of statuses with that hashtag. Now
`StatusListActivity` and `ViewThreadActivity` have a circular
dependency.
Even if that doesn't happen the dependency means that any changes to B
will trigger a rebuild of A, even if the changes to B are not relevant.
Break this dependency by adding a `:core:navigation` module with an
`app.pachli.core.navigation` package that contains `Intent` subclasses
that should be used instead. The `quadrant` plugin is used to generate
constants that can be used to launch activities by name instead of by
class, breaking the dependency chain.
The plugin uses the `Activity` names from the manifest, so when an
activity is moved in the future the constant will automatically update
to reflect the new package name.
If the activity's intent requires specific extras those are passed via
the constructor, with companion object methods to extract them from the
intent.
Using the intent classes from this package is enforced by a lint
`IntentDetector` which will warn if any intents are created using a
class literal.
See #291
Nik Clayton