Cicerone (a guide, one who conducts sightseers) is a lightweight library that makes the navigation in an Android app easy.
It was designed to be used with the MVP pattern (try Moxy), but will work great with any architecture.
- is not tied to Fragments
- not a framework
- short navigation calls (no builders)
- lifecycle-safe!
- functionality is simple to extend
- suitable for Unit Testing
Add the dependency in your build.gradle:
dependencies {
//Cicerone
compile 'ru.terrakok.cicerone:cicerone:X.X.X'
}Initialize the library (for example in your Application class):
public class SampleApplication extends MvpApplication {
public static SampleApplication INSTANCE;
private Cicerone<Router> cicerone;
@Override
public void onCreate() {
super.onCreate();
INSTANCE = this;
initCicerone();
}
private void initCicerone() {
cicerone = Cicerone.create();
}
public NavigatorHolder getNavigatorHolder() {
return cicerone.getNavigatorHolder();
}
public Router getRouter() {
return cicerone.getRouter();
}
}
Presenter calls navigation method of Router.
public class SamplePresenter extends Presenter<SampleView> {
private Router router;
public SamplePresenter() {
router = SampleApplication.INSTANCE.getRouter();
}
public void onBackCommandClick() {
router.exit();
}
public void onForwardCommandClick() {
router.navigateTo("Some screen");
}
}Router converts the navigation call to the set of Commands and sends them to CommandBuffer.
CommandBuffer checks whether there are "active" Navigator:
If yes, it passes the commands to the Navigator. Navigator will process them to achive the desired transition.
If no, then CommandBuffer saves the commands in a queue, and will apply them as soon as new "active" Navigator will appear.
protected void executeCommand(Command command) {
if (navigator != null) {
navigator.applyCommand(command);
} else {
pendingCommands.add(command);
}
}Navigator processes the navigation commands. Usually it is an anonymous class inside the Activity.
Activity provides Navigator to the CommandBuffer in onResume and removes it in onPause.
Attention: Use onResumeFragments() with FragmentActivity (more info)
@Override
protected void onResume() {
super.onResume();
SampleApplication.INSTANCE.getNavigatorHolder().setNavigator(navigator);
}
@Override
protected void onPause() {
super.onPause();
SampleApplication.INSTANCE.getNavigatorHolder().removeNavigator();
}
private Navigator navigator = new Navigator() {
@Override
public void applyCommand(Command command) {
//implement commands logic
}
};This commands set will fulfill the needs of the most applications. But if you need something special - just add it!
- Forward - Opens new screen
- Back - Rolls back the last transition
- BackTo - Rolls back to the needed screen in the screens chain
- Replace - Replaces the current screen
- SystemMessage - Shows system message (Alert, Toast, Snack, etc.)
The library provides predefined navigators for Fragments to use inside Activity.
To use, just provide it with the container and FragmentManager and override few simple methods.
private Navigator navigator = new SupportFragmentNavigator(
getSupportFragmentManager(), R.id.main_container) {
@Override
protected Fragment createFragment(String screenKey, Object data) {
return SampleFragment.getNewInstance((int) data);
}
@Override
protected void showSystemMessage(String message) {
Toast.makeText(MainActivity.this, message, Toast.LENGTH_SHORT).show();
}
@Override
protected void exit() {
finish();
}
};To see how to add, initialize and use the library and predefined navigators check out the sample.
- idea and code - Konstantin Tskhovrebov (@terrakok)
- architecture advice, documentation and publication - Vasili Chyrvon (@Jeevuz)
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