Android studio fragment set and get android#
We shall assume that we are writing for post-3.0 Android devices and not concern ourselves with the issue of support for older devices. The Fragment API was introduced with Android 3.0 (Honeycomb), but it is possible toĭeploy fragments on older platforms through special In addition, we shall see that fragments define pieces of the user interface that we can interact with dynamically, programatically adding them, removing them, or replacing them with other fragments, thereby providing even more flexibility in implementing user interfaces. This gives us considerable leeway in using fragments to alter the user interface in differing circumstances, such as when the same application is displayed in vertical or horizontal mode on a device, or when the same application is deployed on a phone with a smaller screen or on a tablet with a larger screen. The utility of fragments derives from their flexibility: while a fragment must be paired with an activity, it doesn't have to be paired with the same activity each time it is instantiated, and an activity can contain more than one fragment. For example, if the activity is stopped no fragments inside of it can be started, and when the activity is destroyed all fragments that it contains will be destroyed. The most fundamental is that a fragment runs within a larger activity: a fragment cannot exist apart from an activity, and the fragment lifecycle is dependent on the lifecycle of the activity. In that sense it is like an Activity, but with some important differences. On the ON_DESTROYevent, sent when onDestroyView is about to be called, we null out our backing property.This project introduces the basic idea of Fragments, which are an essential part of modern Android programming and will be used in various ways for some of the following projects.Ī Fragment is basically a piece of the user interface or a behavior that has its own lifecycle (see this Finally, when the View’s Lifecycle Owner changes, we observe the new Lifecycle.AndroidX Fragment makes it easy for us, by including viewLifecycleOwnerLiveData, which emits the new Lifecycle Owner when the View is recreated. A Fragment’s View can be created and destroyed many times, so it may have more than one Lifecycle. In the init block, we observe the Fragments viewLifecycleOwner.We construct an anonymous class which implements ReadWriteProperty and LifecycleObserver, allowing us to listen to Lifecycle Events.viewLifecycle() returns a ReadWriteProperty, an implementation of a property of a Fragment, which is of the generic type T.viewLifecycle() is an extension function of Fragment, meaning we can use Fragment-related properties.For example: override fun onCreateView( inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle? ): View? Using this binding in a Fragment takes one more step - inflating it in onCreateView, and returning the root view. This class contains two fields, name and button, which refer to the views in our layout file. This then generates a “binding” class, ResultProfileBinding. Let’s take a look at the example from the View Binding Documentation. Let’s explore how we can use it, in a safe and easy way! View Binding in Fragments We’re likely all going to be using it in Fragments. It’s quick and easy to enable, and allows for type-safe view access. View Binding is an upcoming feature in Android, available in Android Studio 3.6 Canary 11+ which allows you to more easily interact with Views.