Smashing your Android App Into Fragments

Tom Opgenorth | tom@opgenorth.net

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1. Whats the Problem? 2. What Are Fragments? 3. How Do I Use Fragments 4. Look at Code! 5. What about Backwards

Compatibility?

Things We’ll Talk About

What Involved

What’s the Problem?

Screen Sizes & Densities

Fragments To The Rescue!

What is Fragment?

A Fragment represents a behaviour or portion of user

interface in an Activity.

❖ User Interface “modules” ❖ Can share Fragments across different

activity ❖ On Activity can have many

fragments ❖ Different screen sizes have different

layouts

What are Fragments?

❖ Android 3.0 or Higher (well, sort of/not really) ❖ Subclass the Fragment base class ❖ They can load Layout files / Create it’s UI similar to an Activity ❖ There are specialized fragments ❖ Fragments have a lifecycle, just like Activities

Fragment Basics

Fragment Lifecycle

Start

OnInflate OnAttach

OnCreate

OnCreateView

OnActivityCreated

OnStart

OnResumeOnPause

OnStop

OnDestroyView

OnDestroy

OnDetachRunning

End

Fragment Lifecycle (Realistically)

Start

OnInflate OnAttach

OnCreate

OnCreateView

OnActivity

CreatedOnStart

OnResumeOnPause

OnStop

OnDestroyView

OnDestroy

OnDetachRunning

End

How Do I Create Fragments?

Fragments Need Help❖ Must be hosted in an Activity ❖ Activities are Not Directly Aware of

their Fragments ❖ Fragments are aware of their host

Activity ❖ Fragments are not aware of other

Fragments ❖ FragmentManager is the middle man

Fragment Manager

Activity

FragmentManager

FragmentFragmentFragmentFragment Find Fragment

1. Activity looking for a Fragment

2. Searches Fragments

3. Found the request Fragment

Adding a Static Fragment<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="fill_parent"> <fragment class="net.opgenorth.shakespeare.TitlesFragment" android:id="@+id/titles_fragment" android:layout_width="fill_parent" android:layout_height="fill_parent" /> </LinearLayout>

Adding a Dynamic Fragment

// Make new fragment to show this selection. DetailsFragment details = new DetailsFragment();

// Execute a transaction, adding the fragment to the FrameLayout. FragmentTransaction ft = FragmentManager.beginTransaction(); ft.add(Resource.Id.details, details, "details_fragment"); ft.commit();

Show Me The Code!

Backwards Compatibility

Android Support Libraries❖ A set of code libraries that provide

backwards compatibility and features to older API levels

❖ Building a Dynamic UI with Fragments - http://developer.android.com/training/basics/fragments/index.html

❖ Support Libraries - http://developer.android.com/tools/support-library/index.html

Links / References

Thank You!Questions?