This page explains best practices for interacting with the Navigation map in your app.
Use SupportNavigationFragment instead of NavigationView, whenever possible
SupportNavigationFragment is a wrapper for the convenience of handling the
NavigationView lifecycle callbacks, so you don't need to manage these
callbacks themselves. This method is less error-prone and the preferred way to
use Navigation in your app. When using SupportNavigationFragment, be sure not
to invoke NavigationView lifecycle events.
If using NavigationView, use strict ordering when invoking lifecycle methods
NavigationView hosts the Navigation map and closely follows the lifecycle
events as Android activities and fragments, taking specific actions when these
lifecycle events are invoked. NavigationView executes multiple initializations
on NavigationView#onCreate and NavigationView#onStart, and cleanups on
NavigationView#onStop and NavigationView#onDestroy, as well as when other
lifecycle events are processed.
NavigationView lifecycle methods have the same meaning as they do for Android
activities or fragments. For example, onCreate() of NavigationView roughly
translates to and should be invoked by lifecycle callbacks from the Android
activity or fragment. Since the NavigationView lifecycle callbacks are based
on and invoked in the same order as the Android lifecycle callbacks, strong
ordering of these NavigationView methods is required. Otherwise, you may
experience memory
leaks, UI
errors, location not being updated, and other issues.
For more information about the Android activity lifecycle, see the Activity-lifecycle concepts section in the Android developer documentation.
The following table shows when other lifecycle methods should be invoked, after specified lifecycle methods:
| Lifecycle method | Invoked where in the activity lifecycle | Invoked after which lifecycle method |
|---|---|---|
onConfigurationChanged()
|
Invoked when the UI is in the foreground and the configuration changes. | Always after onStart()
|
onTrimMemory()
|
Invoked when an activity is in the background. | Always after onPause()
|
onSaveInstance()
|
Invoked before an activity is destroyed. | Always after onStop()
|
Don't call these lifecycle methods multiple times without calling the
corresponding closing method first. In addition, keep in mind that if some of
these Android lifecycle callbacks are managed by the app itself, and the
NavigationView is added to the fragment after creation or start, the app
should call the specific methods themselves in proper order in order to
correctly initialize the Navigation SDK.
For additional guidance on using these methods, see the Navigation SDK demo app.
If using NavigationView, invoke lifecycle events from the activity or fragment, not both
To keep the strict ordering of the lifecycle methods, invoke these events from either the activity or fragment lifecycle callbacks, which receive these events in order. This approach ensures that apps don't need to coordinate between fragments and activities and cause duplicate calls.