Living on a green rocket field - GDG Berlin Android meetup

At Google IO 2018 the Android team announced Jetpack for Android, which is an opinionated set of libraries and architecture, which is a recommendation for Android developers. We wanted to share our experience with Jetpack and also give some recommendations for all the library & SDK developers.

Transcript

1. @alosdev GDG Berlin Android 09
   Living on a green rocket
   field
   Hasan Hosgel
   alpha
   

   View Slide

2. @alosdev GDG Berlin Android 09
   The King is dead - long live the king
   

   View Slide

3. @alosdev GDG Berlin Android 09
   History
   

   View Slide

4. @alosdev GDG Berlin Android 09
   Timetable
   2011/03 - 1st version Support Library - ActionBarSherlock
   2012/03 - Notification Compat
   2013/07 - App Compat, Media Router
   2014/10 - RecyclerView, CardView
   2015/08 - bunch of new libraries
   2016/08 - split support libs
   2017/06 - multidex
   …
   source: https://developer.android.com/topic/libraries/support-library/revisions
   

   View Slide

5. @alosdev GDG Berlin Android 09
   What now?
   

   View Slide

6. @alosdev GDG Berlin Android 09
   Welcome Jetpack
   

   View Slide

7. @alosdev GDG Berlin Android 09
   android.support.v4.***
   ->
   androidx.***
   Except
   com.google.android.material.***
   

   View Slide

8. @alosdev GDG Berlin Android 09
   gradle.properties
   android.useAndroidX = true
   android.enableJetifier = true
   

   View Slide

9. @alosdev GDG Berlin Android 09
   Jetpack components
   ● Foundation
   ● Architecture
   ● Behaviour
   ● UI
   

   View Slide

10. @alosdev GDG Berlin Android 09
    Foundation libraries
    ● AppCompat
    ● Android KTX
    ● MultiDex
    ● Test
    NEW
    

    View Slide

11. @alosdev GDG Berlin Android 09
    Android KTX
    Kotlin Extension for a bunch of jetpack libraries:
    ● Core-ktx
    ● Fragment-ktx
    ● Lifecycle-ktx
    ● navigation-ktx
    

    View Slide

12. @alosdev GDG Berlin Android 09
    Architecture libraries
    ● DataBinding
    ● Lifecycles
    ● LiveData
    ● Navigation
    ● Paging
    ● Room
    ● ViewModel
    ● WorkManager
    NEW
    NEW
    NEW
    

    View Slide

13. @alosdev GDG Berlin Android 09
    Navigation
    ● Navigation Controller
    ● “easily” update in a wysiwyg editor, also via xml
    ● new resource type navigation
    

    View Slide

14. @alosdev GDG Berlin Android 09
    Navigation graph
    app:startDestination="@id/blankFragment">
    android:id="@+id/blankFragment"
    android:name="com.example.cashdog.cashdog.BlankFragment"
    android:label="fragment_blank"
    tools:layout="@layout/fragment_blank" />
    android:id="@+id/blankFragment2"
    android:name="com.example.cashdog.cashdog.BlankFragment2"
    android:label="Blank2"
    tools:layout="@layout/fragment_blank_fragment2" />
    
    

    View Slide

15. @alosdev GDG Berlin Android 09
    Layout file
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/my_nav_host_fragment"
    android:name="androidx.navigation.fragment.NavHostFragment"
    app:navGraph="@navigation/nav_graph"
    app:defaultNavHost="true"/>
    
    

    View Slide

16. @alosdev GDG Berlin Android 09
    Using NavigationController
    view.findNavController().navigate(R.id.viewTransactionsAction)
    button.setOnClickListener(Navigation.createNavigateOnClickListener(R.id.next_fragment, null))
    val navigationView = findViewById(R.id.nav_view)
    navigationView.setupWithNavController(navController)
    

    View Slide

17. @alosdev GDG Berlin Android 09
    Parameterized navigation
    android:id="@+id/confirmationFragment"
    android:name="com.example.cashdog.cashdog.ConfirmationFragment"
    android:label="fragment_confirmation"
    tools:layout="@layout/fragment_confirmation">
    
    var bundle = bundleOf("amount" to amount)
    view.findNavController().navigate(R.id.confirmationAction, bundle)
    

    View Slide

18. @alosdev GDG Berlin Android 09
    Parameterized navigation with TypeSafety
    Build.gradle:
    …
    apply plugin: 'androidx.navigation.safeargs'
    …
    Caller side:
    val action = SpecifyAmountFragmentDirections.confirmationAction(amount)
    action.amount = amount
    v.findNavController().navigate(action)
    Consumer side:
    ConfirmationFragmentArgs.fromBundle(arguments).amount
    

    View Slide

19. @alosdev GDG Berlin Android 09
    Navigation in Multi Modules
    ● Include existing navigation graph
    ● Module dependency on the navigation
    graph you want to use
    ● If you don’t want to depend on the other
    module, define the resource id in the base
    ○ no TypeSafety
    

    View Slide

20. @alosdev GDG Berlin Android 09
    Paging
    ● PagedList as data object
    ● DataSource to serve PageList
    ● PagedListAdapter for RecyclerView
    Attention: if you want to manipulate the List itself that is not the way to go
    

    View Slide

21. @alosdev GDG Berlin Android 09
    WorkManager
    ● Successor of JobScheduler, JobDispatcher & AlarmManager
    ● Not depending on Google play services (GMS)
    ○ Usage outside of Google ecosystem
    ● Defining constraints, when to run them ( charging, network, etc.)
    

    View Slide

22. @alosdev GDG Berlin Android 09
    Worker
    class CompressWorker(context : Context, params : WorkerParameters)
    : Worker(context, params) {
    override fun doWork(): Result {
    // Do the work here--in this case, compress the stored images.
    // In this example no parameters are passed; the task is
    // assumed to be "compress the whole library."
    myCompress()
    // Indicate success or failure with your return value:
    return Result.SUCCESS
    // (Returning RETRY tells WorkManager to try this task again
    // later; FAILURE says not to try again.)
    }
    }
    

    View Slide

23. @alosdev GDG Berlin Android 09
    Constraint
    // Create a Constraints object that defines when the task should run
    val myConstraints = Constraints.Builder()
    .setRequiresDeviceIdle(true)
    .setRequiresCharging(true)
    // Many other constraints are available, see the
    // Constraints.Builder reference
    .build()
    

    View Slide

24. @alosdev GDG Berlin Android 09
    Running them
    // ...then create a OneTimeWorkRequest that uses those constraints
    val compressionWork = OneTimeWorkRequestBuilder()
    .setConstraints(myConstraints)
    .build()
    OR
    val compressionWork =
    PeriodicWorkRequestBuilder(12, TimeUnit.HOURS)
    .setConstraints(myConstraints)
    .build()
    // Then enqueue the recurring task:
    WorkManager.getInstance().enqueue(compressionWork)
    

    View Slide

25. @alosdev GDG Berlin Android 09
    Worker chains
    val chain1 = WorkManager.getInstance()
    .beginWith(workA)
    .then(workB)
    val chain2 = WorkManager.getInstance()
    .beginWith(workC)
    .then(workD)
    val chain3 = WorkContinuation
    .combine(chain1, chain2)
    .then(workE)
    chain3.enqueue()
    

    View Slide

26. @alosdev GDG Berlin Android 09
    Behaviour libraries
    ● Download Manager
    ● Media & Playback
    ● Notifications
    ● Permission
    ● Sharing
    ● Slices NEW
    

    View Slide

27. @alosdev GDG Berlin Android 09
    Slices
    ● Currently not visible for users, but you can be first movers
    ● Like widgets for the home screen, just in other apps
    ● Supported API level 19 (KitKat) onwards
    ● Can be used with Actions
    

    View Slide

28. @alosdev GDG Berlin Android 09
    UI libraries
    ● Animation & transitions
    ● Auto
    ● Emoji
    ● Fragment
    ● Layout
    ● Palette
    ● TV
    ● Wear OS by Google
    

    View Slide

29. @alosdev GDG Berlin Android 09
    Jetpack - sample app
    https://github.com/googlesamples/android-sunflower
    

    View Slide

30. @alosdev GDG Berlin Android 09
    Wishlist for libraries/ SDKs
    ● Don’t force your user to a specific marshaller (GSON, Jackson, Moshi)
    ○ Offer the functionality like Retrofit and the ConverterFactory
    ● Don’t force your user to use Rx- there is a cool guy around => Coroutine
    ○ Droidcon Panel discussion “Rx must die!?”
    ○ From Rx monolith to Coroutines + multi modules
    by Ivan Morgillo
    ● Don’t depend on bigger libraries, especially if just use a small part of it
    ● Add proguard config in your Jar/ Aar and don’t widen it to much
    

    View Slide

31. @alosdev GDG Berlin Android 09
    Any Questions
    

    View Slide