Android-practice-6-Fragment

Creating and adding a fragment to the main layout

Fragment is reusable portion of UI. In other words, a modular section of an activity. Multiple fragments can be in a single activity for a multi-pane UI, also one fragment can be reused in multiple activities.

When we want to make two different screens, and if they have some navigational relationship, we would go for fragment-fragment rather than activity-activity.

Adding a Fragment class

• When you add a Fragment class, a class that extends Fragment class will be generated. Take a look at the overriden onCreateView(..) method.

  override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?)
      : View? {
      // Inflate the layout for this fragment
      return inflater.inflate(R.layout.fragment_title, container, false)
  }
  

  This method returns the root view of inflated view hierarchy for the fragment. We are going to replace this method with DataBindingUtil.inflate(..) so we can use the binding object to the layout.

Creating a binding object to Fragment layout

• DataBinding.inflate(..) method will inflate the layout and return the binding object. binding.root contains the inflated view.

  override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?)
      : View? {
      val binding = DataBindingUtil.inflate<FragmentTitleBinding>(inflater, R.layout.fragment_title, container, false)
      return binding.root
  }
  

Adding fragment to the main layout

• Use <fragment> element in layout file to add the fragment. The name attribute is going to be the name of the Fragment class with it's full path.

  <fragment
      android:id="@+id/titleFragment"
      android:name="com.example.fragmentpractice.TitleFragment"
      .. />