![]() With Up navigation, each Activity is arranged in a hierarchy, and each "child" Activity shows a left-facing arrow in the app bar Up button (in app bar) that returns the user to the "parent" Activity. Up navigation, sometimes referred to as ancestral or logical navigation, is used to navigate within an app based on the explicit hierarchical relationships between screens. There may, however, be times where you may want to override the default behavior for tasks or for the back stack. ![]() In most cases you don't have to worry about managing either tasks or the back stack for your app-the system keeps track of these things for you, and the back button is always available on the device. Android enables the user to navigate between tasks with the overview or recent tasks screen, accessible with the square button on lower right corner of the device. Navigating with the Back button returns only to the Activity in the current task, not for all tasks running on the device. If the user returns to the first app, that first task's back stack returns. If the user uses an app for a while, taps home, and starts a new app, that new app launches in its own task and has its own back stack. Most tasks start from the Android home screen, and tapping an app icon starts a task (and a new back stack) for that app. A task is an organizing concept for each Activity the user interacts with when performing an operation, whether they are inside your app or across multiple apps. TasksĪndroid provides a back stack for each task. Each time the user presses the Back button, each Activity in the stack is popped off to reveal the previous one, until the user returns to the Home screen. The previous Activity is stopped but is still available in the back stack.īecause an app can start an Activity both inside and outside a single app, the back stack contains each Activity that has been launched by the user in reverse order. Each time a new Activity starts, it is pushed onto the back stack and takes user focus. The back stack is the set of each Activity that the user has visited and that can be returned to by the user with the back button. Back navigation is also called temporal navigation because the back button navigates the history of recently viewed screens, in reverse chronological order. Up (ancestral) navigation, provided by you as an option in the app bar.īack navigation allows your users to return to the previous Activity by tapping the device back button.Back (temporal) navigation, provided by the device Back button, and the back stack.Thoughtfully designing your app's navigation will make using your app predictable and reliable for your users.Īndroid system supports two different forms of navigation strategies for your app. Few things frustrate users more than basic navigation that behaves in inconsistent and unexpected ways. As your users move around your app and from one Activity to another, consistent navigation becomes more important to the app's user experience. Protected override void OnCreate ( Bundle savedInstanceState ) Īny app of any complexity that you build will include more than one Activity. When you create a new activity from the wizard, you get the code as follows: To create an Activity in Visual Studio, Add New file, choose Android and choose Activity and give a name to the class. Implement a basic UI for the Activity in an XML layout file.Create a class that inherits from the AppCompatActivity or Activity.To implement an Activity in your app, do the following: The activity is notified of each state by the system using life cycle methods. ![]() ![]() The system maintains the previous activity state.
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