Fragments are modular sections of an activity that have their own lifecycle and can be added or removed dynamically. Fragments are embedded within activities and use the activity's lifecycle. They allow building reusable UI components and supporting multi-pane layouts on larger screens. Fragments should be used when building multi-pane UIs or when wanting to reuse certain UI components across multiple activities. The document provides details on how to define fragments in XML layouts, add them programmatically, communicate between fragments and activities, and best practices for using fragments.

1. Easy to understand
Fragment

2. What is fragment?
Is it another type of Activity?
Does it replace Activity?
Or is it a new component ?

3. What is fragment?
Is it another type of Activity?
Does it replace Activity?
Or is it a new component ?
It is a modular section of an activity!!

4. Relationship with Activity
Embedded in an activity surely
Depend on activity lifecycle
Inside activity’s view hierarchy

5. Fragment advantage
Multi-pane UI support
Reuse component
Add or remove component dynamically

6. When to use fragment

7. Multi-pane UI support

13. How to use fragment
1 <fragment
2 android:id="@+id/list"
3 android:name=“com.new.ExampleFragment"
4 android:layout_width="match_parent"
5 android:layout_height="match_parent" />
Inside the activity’s layout

14. Add fragment programmatically
1 FragmentManager fm = getFragmentManager();
2 FragmentTransaction ft = fm.beginTransaction();
3 ExampleFragment fragment = new ExampleFragment();
4 ft.add(R.id.fragment_container, fragment);
5 ft.commit();
1 <FrameLayout
2 android:id="@+id/fragment_container"
3 android:layout_width="wrap_content"
4 android:layout_height=“wrap_content"/>

15. Fragment Transactions
1 FragmentTransaction ft = fm.beginTransaction();
2 ft.add(R.id.fragment_container, fragment);
3 ft.replace(R.id.fragment_container, fragment);
Modify fragment
4 ft.show(fragment)
5 ft.hide(fragment)
6 ft.remove(fragment)
Modify fragment already in activity
Set transition style
7 ft.setTransition(TRANSIT_FRAGMENT_CLOSE)
8 ft.setCustomAnimations(entet,exit)

16. Fragment Communication
Just like activity communication directly?

17. Fragment Communication
Just like activity communication directly?
Communicate through activity !

18. Main Activity
fragment
Controller

19. Main Activity
fragment
Controller

20. 1 public class ChannelDetailFragment extends Fragment {
2 private OnChannelClickListener mCallback;
3
4 public interface OnChannelClickListener {
5 public void onChannelClick(int channelNumber);
6 }
7 @Override
8 public void onAttach(Activity activity) {
9 super.onAttach(activity);
10 try {
11 mCallback = (OnChannelClickListener) activity;
12 } catch (ClassCastException e) {
13 throw new ClassCastException(activity.toString()
14 + " must implement OnChannelClickListener");
15 }
16 }
17 public boolean onClick(View v) {
18 mCallback.onChannelClick(channelNumber);
19 }
In fragment file

21. In activity file
1 public class Activity extends Activity
2 implements OnChannelClickListener {
3
4 @Override
5 public void onChannelClick(int channelNumber){
6 // do something or open another fragment.
7 }
8 }

22. Fragment view
Use setContentView() to set view?

23. Fragment view
Use setContentView() to set view?
1 @Override
2 public View onCreateView(LayoutInflater inflater, ViewGroup
3 container, Bundle savedInstanceState) {
4 View root = inflater.inflate(R.layout.fragment_layout,
5 container, false);
6 //init other view
7 return root;
8 }
Use onCreateView callback to set view !

24. Fragment tips
Toast.makeText(getActivity(), "Mission complete",
Toast.LENGTH_LONG);
Get context from activity
Add to BackStack
1 FragmentManager fm = getFragmentManager();
2 FragmentTransaction ft = fm.beginTransaction();
3 ft.replace(R.id.fragment_container, fragment);
4 ft.addToBackStack(null);

25. Import v4 or origin version
1 import android.support.v4.app.FragmentActivity;
2 import android.support.v4.app.FragmentManager;
3 import android.support.v4.app.FragmentTransaction;
4 import android.support.v4.app.Fragment;
1 import android.app.Activity;
2 import android.app.FragmentManager;
3 import android.app.FragmentTransaction;
4 import android.app.Fragment;

26. Use new Fragment() or
Fragment.newInstance()?
1 ChannelFragment fragment = new ChannelFragment();
2 Bundle args = new Bundle();
3 args.putInt(CHANNEL_PAGE_INDEX, index);
4 fragment.setArguments(args);

27. 1 public static ChannelFragment newInstance(int index) {
2 ChannelFragment fragment = new ChannelFragment();
3 Bundle args = new Bundle();
4 args.putInt(CHANNEL_PAGE_INDEX, index);
5 fragment.setArguments(args);
6 return fragment;
7 }
ChannelFragment.newInstance(index);
Use static factory method for better!

28. Thank you!
Fantasy