Android tutorial - Android Fragments - android app development - android studio - android development tutorial
What is Fragments?
- A Fragment is a piece of an activity which enable more modular activity design. It will not be wrong if we say, a fragment is a kind of sub-activity. A fragment has its own layout and its own behavior with its own life cycle callbacks.
- You can add or remove fragments in an activity while the activity is running.
- You can combine multiple fragments in a single activity to build a multi-plane UI.
- Android Fragment is the part of activity, it is also known as sub-activity. There can be more than one fragment in an activity. Fragments represent multiple screen inside one activity.
- Android fragment lifecycle is affected by activity lifecycle because fragments are included in activity.
- Each fragment has its own life cycle methods that is affected by activity life cycle because fragments are embedded in activity.
- The Fragment Manager class is responsible to make interaction between fragment objects.
Android Fragment Lifecycle
- The lifecycle of android fragment is like the activity lifecycle. There are 12 lifecycle methods for fragment.
|1.||onAttach(Activity)||it is called only once when it is attached with activity.|
|2.||onCreate(Bundle)||It is used to initialize the fragment.|
|3.||onCreateView(LayoutInflater, ViewGroup, Bundle)||creates and returns view hierarchy.|
|4.||onActivityCreated(Bundle)||It is invoked after the completion of onCreate() method.|
|5.||onViewStateRestored(Bundle)||It provides information to the fragment that all the saved state of fragment view hierarchy has been restored.|
|6.||onStart()||makes the fragment visible.|
|7.||onResume()||makes the fragment interactive.|
|8.||onPause()||is called when fragment is no longer interactive.|
|9.||onStop()||is called when fragment is no longer visible.|
|10.||onDestroyView()||allows the fragment to clean up resources.|
|11.||onDestroy()||allows the fragment to do final clean up of fragment state.|
|12.||onDetach()||It is called immediately prior to the fragment no longer being associated with its activity.|
Android Fragment Example
- Let's have a look at the simple example of android fragment.