Fragment in Android can be found through

Fragment in Android can be found through

Asked on January 18, 2019 in Android.
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  • 9 Answer(s)

    Using FragmentManager.findFragmentByID(R.id.fragment), we can find the fragment/fragments which are placed on the layout

    Answered on January 18, 2019.
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    Fragments:

    A fragment is a reusable class implementing a portion of an activity. A Fragment typically defines a part of a user interface. Fragments must be embedded in activities; they cannot run independently of activities.

    Looking Up a Fragment Instance

    Often we need to lookup or find a fragment instance within an activity layout file. There are a few methods for looking up an existing fragment instance:

    1. ID – Lookup a fragment by calling findFragmentById on the FragmentManager
    2. Tag – Lookup a fragment by calling findFragmentByTag on the FragmentManager
    3. Pager – Lookup a fragment by calling getRegisteredFragment on a PagerAdapter

    Each method is outlined in more detail below.

    Finding Fragment By ID

    If the fragment was statically embedded in the XML within an activity and given an android:id such as fragmentDemo then we can lookup this fragment by id by calling findFragmentById on the FragmentManager:

    public class MainActivity extends AppCompatActivity {
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            if (savedInstanceState == null) {
              DemoFragment fragmentDemo = (DemoFragment) 
                  getSupportFragmentManager().findFragmentById(R.id.fragmentDemo);
            }
        }
    }

    Finding Fragment By Tag

    If the fragment was dynamically added at runtime within an activity then we can lookup this fragment by tag by calling findFragmentByTag on the FragmentManager:

    public class MainActivity extends AppCompatActivity {
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            if (savedInstanceState == null) {
              // Let's first dynamically add a fragment into a frame container
              getSupportFragmentManager().beginTransaction(). 
                  replace(R.id.flContainer, new DemoFragment(), "SOMETAG").
                  commit();
              // Now later we can lookup the fragment by tag
              DemoFragment fragmentDemo = (DemoFragment) 
                  getSupportFragmentManager().findFragmentByTag("SOMETAG");
            }
        }
    }

    Finding Fragment Within Pager

    If the fragment was dynamically added at runtime within an activity into a ViewPager using a FragmentPagerAdapter then we can lookup the fragment by upgrading to a SmartFragmentStatePagerAdapter as described in the ViewPager guide. Now with the adapter in place, we can also easily access any fragments within the ViewPager using getRegisteredFragment:

    // returns first Fragment item within the pager
    adapterViewPager.getRegisteredFragment(0); 

    Note that the ViewPager loads the fragment instances lazily similar to the a ListView recycling items as they appear on screen. If you attempt to access a fragment that is not on screen, the lookup will return null.

    Answered on February 4, 2019.
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    Fragments are tiny independent sets of functionality. They are widgets which can be used to be displayed in any part of the code.

    A fragment has capability to perform every action that can be done in an activity other than just few. These fragments can be placed in any activity.

    Interaction with fragments is done through FragmentManager.

    The following lifecycle events come into play when you add a fragment

     onAttach

     onCreate

     onCreateView

     onActivityCreated

     onStart

     onResume

     onPause

     onStop

     onDestroyView

     onDestroy

     onDetach

    When and where are Fragments used?

    Fragments are used whenever there is a need to write a specific piece of code to show the same UI.

    It can be independently developed and can be placed in different Activities.

    Answered on February 6, 2019.
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    in an Activity. Interaction with fragments is done through FragmentManager, which can be obtained via Activity.getFragmentManager() and Fragment.getFragmentManager().

    FragmentManager.findFragmentById(int id)

    Finds a fragment that was identified by the given id either when inflated from XML or as the container ID when added in a transaction.

    Answered on February 24, 2019.
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    Fragments are tiny independent sets of functionality. They are widgets which can be used to be displayed in any part of the code.

    A fragment has capability to perform every action that can be done in an activity other than just few. These fragments can be placed in any activity.

    Interaction with fragments is done through FragmentManager.

    The following lifecycle events come into play when you add a fragment

     onAttach

     onCreate

     onCreateView

     onActivityCreated

     onStart

     onResume

     onPause

     onStop

     onDestroyView

     onDestroy

     onDetach

    When and where are Fragments used?

    Fragments are used whenever there is a need to write a specific piece of code to show the same UI.

    It can be independently developed and can be placed in different Activities.

    InteractiveUX is a leading company in Mobile Development Services, you could explore more at their website.

    Answered on February 24, 2019.
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    Fragment is a combination of an XML layout file and a java class much like an Activity . Using the support library, fragments are supported back to all relevantAndroid versions. Fragments encapsulate views and logic so that it is easier to reuse within activities.

    Answered on February 24, 2019.
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    fragment is usually used as part of an activity’s user interface and contributes its own layout to the activity. To provide a layout for a fragment, you must implement the onCreateView() callback method, which the Android system calls when it’s time for the fragment to draw its layout.

    Answered on February 24, 2019.
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    Fragment represents a behavior or a portion of user interface in a FragmentActivity. You can combine multiple fragments in a single activity to build a multi-pane UI and reuse a fragment in multiple activities. You can think of a fragment as a modular section of an activity, which has its own lifecycle, receives its own input events, and which you can add or remove while the activity is running (sort of like a “sub activity” that you can reuse in different activities).

    Answered on February 24, 2019.
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    A fragment must always be hosted in an activity and the fragment’s lifecycle is directly affected by the host activity’s lifecycle. For example, when the activity is paused, so are all fragments in it, and when the activity is destroyed, so are all fragments. However, while an activity is running (it is in the resumed lifecycle state), you can manipulate each fragment independently, such as add or remove them. When you perform such a fragment transaction, you can also add it to a back stack that’s managed by the activity—each back stack entry in the activity is a record of the fragment transaction that occurred.

    Answered on February 24, 2019.
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