Secrets of Android Jetpack

In recent years, Android Jetpack has been developing at an incredible pace and keeping track of all the new products is not easy. The report will provide an overview of the latest API and the future of their AndroidX, which are changing the approach to developing Android apps.

Transcript

1. SECRETS OF ANDROID JETPACK
   KIRILL ROZOV / REPLIKA.AI
   

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2. • Activity
   • Fragment
   • Core
   • ViewModel
   • LiveData
   • Navigation
   AGENDA
   2
   

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3. • Develop Android apps for 8+ years
   • Kotlin Lover
   • Mobile Lead at Replika.ai
   • Author of “Android Broadcast” Project
   • Cohost of Android Dev Virtual Meetups
   • Cohost of Mobile People Talks podcast
   WHO AM I?
   KIRILL ROZOV
   @kirill_rozov @krlrozov
   

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5. ACTIVITY
   

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6. class MainActivity : AppCompatActivity() {
   
   override fun onCreate(savedInstanceState: Bundle?) {
   
   super.onCreate(savedInstanceState)
   
   setContentView(R.layout.activity_main)
   
   }
   
   }
   
   CONTENT VIEW
   6
   

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7. class MainActivity : AppCompatActivity(R.layout.activity_main)
   CONTENT VIEW
   7
   

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8. class MainActivity : AppCompatActivity() {
   
   var pictureUri: Uri? = null
   
   fun onPictureTaken(uri: Uri?, isImageSaved: Boolean) {
   
   "# Process the image
   
   }
   
   fun takePicture() {
   
   val pictureUri: Uri = Uri.fromFile(File.createTempFile("androidx-secrets", System.currentTimeMillis().toString()))
   
   this.pictureUri = pictureUri
   
   val intent = Intent(MediaStore.ACTION_IMAGE_CAPTURE).putExtra(MediaStore.EXTRA_OUTPUT, pictureUri)
   
   startActivityForResult(intent, REQUEST_CODE_TAKE_PHOTO)
   
   }
   
   override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
   
   if (requestCode "$ REQUEST_CODE_TAKE_PHOTO) {
   
   onPictureTaken(pictureUri, resultCode "$ Activity.RESULT_OK)
   
   } else {
   
   super.onActivityResult(requestCode, resultCode, data)
   
   }
   
   }
   
   companion object {
   
   const val REQUEST_CODE_TAKE_PHOTO = 1
   
   }
   
   }
   ACTIVITY RESULT
   8
   

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9. class MainActivity : AppCompatActivity() {
   
   var pictureUri: Uri? = null
   
   val takePhoto = registerForActivityResult(TakePicture()) { isImageSaved "#
   
   onPictureTaken(pictureUri, isImageSaved)
   
   this.pictureUri = null
   
   }
   
   fun onPictureTaken(uri: Uri?, isImageSaved: Boolean) {
   
   "# Process the image
   
   }
   
   fun takePicture() {
   
   val pictureUri =
   
   Uri.fromFile(File.createTempFile("androidx-secrets", System.currentTimeMillis().toString()))
   
   this.pictureUri = pictureUri
   
   takePhoto.launch(pictureUri)
   
   }
   
   ACTIVITY RESULT API
   9
   

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10. class TakePicture : ActivityResultContract() {
    
    override fun createIntent(context: Context, input: Uri): Intent {
    
    return Intent(MediaStore.ACTION_IMAGE_CAPTURE)
    
    .putExtra(MediaStore.EXTRA_OUTPUT, input)
    
    }
    
    override fun getSynchronousResult(
    
    context: Context, input: Uri
    
    ): SynchronousResult? {
    
    return null
    
    }
    
    override fun parseResult(resultCode: Int, intent: Intent?): Boolean {
    
    return resultCode "$ Activity.RESULT_OK
    
    }
    
    }
    ACTIVITY RESULT API
    10
    

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11. • CreateDocument
    • OpenDocument
    • OpenDocumentTree
    • OpenMultipleDocuments
    • GetContent
    • GetMultipleContent
    • PickContact
    • StartActivityForResult
    • StartIntentSenderForResult
    • TakePicture
    • TakePicturePreview
    • TakeVideo
    • RequestPermission
    • RequestMultiplePermissions
    PREDEFINED CONTRACTS
    11
    

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12. class MainActivity : AppCompatActivity() {
    
    val requestPermissionForTrackUserResult =
    
    registerForActivityResult(RequestPermission()) { permissionGranted "#
    
    if (permissionGranted) {
    
    trackUser()
    
    }
    
    }
    
    @RequiresPermission(Manifest.permission.ACCESS_FINE_LOCATION)
    
    fun trackUser() {
    
    "# Start track user
    
    }
    
    fun requestPermissionForTrackUser() {
    
    requestPermissionForTrackUserResult.launch(Manifest.permission.ACCESS_FINE_LOCATION)
    
    }
    
    }
    ACTIVITY RESULT API FOR PERMISSIONS
    12
    

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13. FRAGMENT
    

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14. class MainFragment : Fragment() {
    
    override fun onCreateView(
    
    inflater: LayoutInflater,
    
    container: ViewGroup?,
    
    savedInstanceState: Bundle?
    
    ): View? {
    
    return inflater.inflate(R.layout.fragment_main, container, false)
    
    }
    
    }
    FRAGMENT’S VIEW
    14
    

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15. class MainFragment : Fragment(R.layout.fragment_main)
    FRAGMENT’S VIEW
    15
    

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16. • Callback via parent Fragment/Activity
    • Target Fragment
    • Shared View Model
    SHARE RESULT
    BETWEEN FRAGMENTS
    16
    

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17. class FromFragment : Fragment() {
    
    override fun onCreate(savedInstanceState: Bundle?) {
    
    super.onCreate(savedInstanceState)
    
    childFragmentManager.setFragmentResultListener(
    
    EndFragment.REQUEST_KEY, this
    
    ) { requestKey: String, result: Bundle "#
    
    val isSuccess = result.getBoolean(EndFragment.KEY_SUCCESS)
    
    "# Do something with the result"%
    
    }
    
    }
    
    fun startFragment() {
    
    childFragmentManager.commit { add(android.R.id.content, EndFragment(), FRAGMENT_END) }
    
    }
    
    }
    FRAGMENT RESULT API
    17
    

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18. class EndFragment : Fragment() {
    
    fun updateResult(success: Boolean) {
    
    val result = bundleOf(KEY_SUCCESS to success)
    
    parentFragmentManager.setFragmentResult(REQUEST_KEY, result)
    
    }
    
    }
    FRAGMENT RESULT API
    18
    

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19. class MainFragment : Fragment() {
    
    @Inject
    
    lateinit var deps: Deps
    
    }
    DI IN FRAGMENT
    19
    

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20. class MainFragment : Fragment() {
    
    @Inject
    
    private lateinit var deps: Deps
    
    }
    DI IN FRAGMENT
    20
    

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21. class MainFragment : Fragment() {
    
    @Inject
    
    private var deps: Deps
    
    }
    DI IN FRAGMENT
    21
    

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22. class MainFragment : Fragment() {
    
    @Inject
    
    private val deps: Deps
    
    }
    DI IN FRAGMENT
    22
    

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23. class MainFragment @Inject constructor(
    
    private val deps: Deps
    
    ) : Fragment()
    DI IN FRAGMENT
    23
    

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24. class FragmentFactory {
    
    open fun instantiate(
    
    classLoader: ClassLoader,
    
    className: String
    
    ): Fragment
    
    }
    FRAGMENT FACTORY
    24
    

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25. class InjectFragmentFactory(
    
    providers: Map, Provider
    ) : FragmentFactory() {
    
    private val providers =
    
    providers.mapKeys { (fragmentClass, _) "# fragmentClass.name }
    
    override fun instantiate(
    
    classLoader: ClassLoader, className: String
    
    ): Fragment {
    
    return providers[className]"'get()
    
    "( super.instantiate(classLoader, className)
    
    }
    
    }
    FRAGMENT FACTORY
    25
    

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26. "# Set the fragmentFactory as default for every FragmentActivity in the app
    
    class SetFragmentFactory(
    
    private val fragmentFactory: FragmentFactory
    
    ) : Application.ActivityLifecycleCallbacks {
    
    override fun onActivityCreated(
    
    activity: Activity, savedInstanceState: Bundle?
    
    ) {
    
    if (activity is FragmentActivity) {
    
    activity.supportFragmentManager.fragmentFactory =
    
    this.fragmentFactory
    
    }
    
    }
    
    }
    FRAGMENT FACTORY
    26
    

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27. • Injection in Fragment constructor
    • No more Component.inject(*Fragment)
    • Less re lection/more performance
    • Possibility to obfuscate Fragments
    FRAGMENT FACTORY
    BONUSES
    27
    

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28. fragmentManager.commit {
    
    add(android.R.id.content, NextFragment(), FRAGMENT_TAG)
    
    }
    FRAGMENT TRANSCATION
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29. fragmentManager.commit {
    
    add(
    
    android.R.id.content,
    
    fragmentClass = NextFragment")class.java,
    
    args = null,
    
    tag = FRAGMENT_TAG
    
    )
    
    }
    FRAGMENT TRANSCATION
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30. fragmentManager.commit {
    
    add(
    
    android.R.id.content,
    
    args = null,
    
    tag = FRAGMENT_TAG
    
    )
    
    }
    
    FRAGMENT TRANSCATION
    30
    

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31. ANDROIDX CORE
    

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32. val builder = SpannableStringBuilder()
    
    builder.append("Hello")
    
    builder.setSpan(
    
    StyleSpan(Typeface.ITALIC), 0, builder.length, SPAN_INCLUSIVE_EXCLUSIVE
    
    )
    
    builder.append(",")
    
    val start = builder.length
    
    builder.append("World!")
    
    builder.setSpan(
    
    StyleSpan(Typeface.BOLD), start, builder.length, SPAN_INCLUSIVE_EXCLUSIVE
    
    )
    BUILD SPANNED STRING
    33
    

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33. buildSpannedString {
    
    italic { append("Hello") }
    
    append(",")
    
    bold { append("World!") }
    
    }
    BUILD SPANNED STRING
    34
    

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34. val activityManager = context.getSystemService(Context.ACTIVITY_SERVICE)
    
    val activityManager = context.getSystemService()
    SYSTEM SERVICES
    35
    

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35. val activityManager: Any? = context.getSystemService(Context.ACTIVITY_SERVICE)
    
    val activityManager: ActivityManager? = context.getSystemService()
    SYSTEM SERVICES
    36
    

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36. val attrs = context.obtainStyledAttributes(
    
    attributes, R.styleable.CustomView, defStyleAttr, 0
    
    )
    
    main = attrs.getBoolean(R.styleable.CustomView_main, false)
    
    attrs.recycle()
    
    CUSTOM VIEW ATTRIBUTES
    37
    

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37. context.withStyledAttributes(
    
    set = attributes,
    
    attrs = R.styleable.CustomView,
    
    defStyleAttr = defStyleAttr
    
    ) {
    
    main = attrs.getBoolean(R.styleable.CustomView_main, false)
    
    }
    
    CUSTOM VIEW ATTRIBUTES
    38
    

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38. fun makeArgs(): Bundle {
    
    val args = Bundle()
    
    args.putString(KEY1, "value")
    
    args.putInt(KEY2, 1)
    
    return args
    
    }
    BUNDLE
    39
    

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39. fun makeArgs(): Bundle {
    
    return Bundle().apply {
    
    putString(KEY1, "value")
    
    putInt(KEY2, 1)
    
    }
    
    }
    BUNDLE
    40
    

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40. fun makeArgs(): Bundle {
    
    return Bundle(2).apply {
    
    putString(KEY1, "value")
    
    putInt(KEY2, 1)
    
    }
    
    }
    BUNDLE
    41
    

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41. fun makeArgs(): Bundle {
    
    return bundleOf(KEY1 to "value", KEY2 to 1)
    
    }
    BUNDLE
    42
    

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42. fun bundleOf(vararg pairs: Pair) = Bundle(pairs.size).apply {
    
    for ((key, value) in pairs) {
    
    when (value) {
    
    null "* putString(key, null)
    
    is Boolean "* putBoolean(key, value)
    
    is Byte "* putByte(key, value)
    
    is Char "* putChar(key, value)
    
    is Double "* putDouble(key, value)
    
    is Float "* putFloat(key, value)
    
    is Int "* putInt(key, value)
    
    is Long "* putLong(key, value)
    
    is Short "* putShort(key, value)
    
    …
    
    }
    
    }
    
    }
    ⚠ UNDER THE HOOD
    43
    

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43. LIFECYCLE
    

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44. class MainFragment : Fragment() {
    
    private val viewModel: MainViewModel =
    
    ViewModelProvider(
    
    this,
    
    MainViewModel.Factory()
    
    ).get(MainViewModel")class.java)
    
    }
    VIEW MODEL CREATION
    45
    

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45. class MainFragment : Fragment() {
    
    private val viewModel: MainViewModel by viewModels {
    MainViewModel.Factory()
    }
    
    }
    VIEW MODEL CREATION
    46
    

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46. class MainFragment @Inject constructor(
    
    private val viewModelFactory: Provider
    
    ) : Fragment() {
    
    private val viewModel: MainViewModel by viewModels {
    viewModelFactory.get()
    }
    
    }
    VIEW MODEL CREATION
    47
    

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47. VIEWMODEL. SAVING STATE
    48
    

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48. "# androidx.lifecycle:lifecycle-viewmodel-savedstate"+version>
    
    class MainViewModel(savedStateHandle: SavedStateHandle) : ViewModel() {
    
    val text: MutableLiveData =
    
    savedStateHandle.getLiveData(STATE_TEXT)
    
    }
    VIEW MODEL. SAVING STATE
    49
    

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49. class MainViewModel(private val githubService: GithubService) : ViewModel() {
    
    val users: LiveData
    while (true) {
    
    var delayDuration = 5_000L "# Ms
    
    try {
    
    emit(githubService.fetchUsers())
    
    break
    
    } catch (e: Exception) {
    
    delay(delayDuration)
    
    delayDuration *= 2
    
    }
    
    }
    
    }
    
    }
    LIVEDATA BUILDER + COROUTINE
    50
    

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50. NAVIGATION
    

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51. 
    
    
    android:name=“HomeViewPagerFragment >
    
    
    app:destination=“@id/plant_detail_fragment" ",
    
    "-fragment>
    
    
    android:name="PlantDetailFragment"
    
    android:label=“@string/plant_detail_title" >
    
    
    "-fragment>
    
    "-navigation>
    NAVIGATION GRAPH. XML
    52
    

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52. navHostFragment.navController.apply {
    
    graph = createGraph(AppNavGraph.id, AppNavGraph.Dest.home) {
    
    fragment(AppNavGraph.Dest.home) {
    
    label = getString(R.string.home_title)
    
    action(AppNavGraph.Action.toPlantDetail) {
    
    destinationId = AppNavGraph.Dest.plantDetail
    
    }
    
    }
    
    fragment(AppNavGraph.Dest.plantDetail) {
    
    label = getString(R.string.plant_detail_title)
    
    argument(AppNavGraph.Args.plantId) {
    
    type = NavType.StringType
    
    }
    
    }
    
    }
    
    }
    
    NAVIGATION GRAPH. KOTLIN DSL
    53
    object AppNavGraph {
    
    const val id = 1
    
    object Dest {
    
    const val home = 2
    
    const val plantDetail = 3
    
    }
    
    object Action {
    
    const val toPlantDetail = 4
    
    }
    
    object Args {
    
    const val plantId = "plantId"
    
    }
    
    }
    

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53. • No preview
    • All ids by your hands
    • No “safe args” plugins
    NAVIGATION GRAPH.
    KOTLIN DSL
    54
    

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54. • Hilt for Dagger 2 (Alpha)
    • Paging 3.0 (Alpha)
    • Benchmark
    • Startup (Alpha)
    • CameraX (Beta)
    • AsyncLayoutIn later
    • Constraint Layout 2.0 (Beta)
    • MotionLayout (Beta)
    • Vector Drawable
    • SavedState
    • Exif Interface
    • RecyclerView
    • and many more…
    MORE JETPACK LIBRARIES
    55
    

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55. THANKS YOU!
    QUESTIONS TIME
    KIRILL ROZOV / REPLIKA.AI
    @kirill_rozov
    @krlrozov
    youtube.com/c/androidbroadcast
    

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