Inside Jetpack

Transcript

1. Inside Jetpack
   Architecture Components
   Hiroyuki Mori
   @moridroid
   

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2. • Started as a Venture between Softbank and Yahoo
   • One of biggest search in Japan
   • Not a part of big
   

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3. What & Why
   Architecture Components
   

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5. View
   View
   Controller
   Application
   Logic
   Network
   Persistent
   Model
   onSendClick
   sendComment
   

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6. onSendClick
   sendComment
   View
   View
   Controller
   Application
   Logic
   Network
   Persistent
   Model
   

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7. View
   View
   Controller
   Application
   Logic
   Network
   Persistent
   Model
   

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8. View
   View
   Controller
   Application
   Logic
   Network
   Persistent
   Model
   subscribe
   

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9. View
   View
   Controller
   Application
   Logic
   Network
   Persistent
   Model
   onSendClick
   sendComment
   

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17. 2018
    -JGFDZDMFT
    -JWF%BUB
    7JFX.PEFM
    3PPN
    1BHJOH
    %BUB#JOEJOH
    /BWJHBUJPO
    8PSL.BOBHFS
    %PXOMPBE.BOBHFS
    .FEJB1MBZCBDL
    1FSNJTTJPOT
    /PUJDBUJPOT
    4IBSJOH
    4MJDFT
    "OJNBUJPO5SBOTJUJPOT
    "VUP 578FBS
    &NPKJ
    'SBHNFOU
    -BZPVU
    1BMFUUF
    "QQ$PNQBU
    "OESPJE,59
    .VMUJEFY
    5FTU
    

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18. -JGFDZDMFT
    -JWF%BUB
    7JFX.PEFM
    3PPN
    1BHJOH
    %BUB#JOEJOH
    /BWJHBUJPO
    8PSL.BOBHFS
    

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19. Lifcycle problems
    

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20. In early days
    

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21. Steve Pomeroy https://github.com/xxv/android-lifecycle CC-BY-SA 4.0
    Today
    

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22. LifecycleObserver
    

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23. Android System
    NetworkReceiver Network state
    Foo Activity
    observe
    observe
    notify
    notify
    state changed
    

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24. class NetworkReceiver(val listener : (NetworkInfo) -> Unit) : BroadcastReceiver() {
    override fun onReceive(context: Context, intent: Intent) {
    val con = context.getSystemService(ConnectivityManager::class.java)
    listener(con.activeNetworkInfo)
    }
    }
    

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25. class NetworkReceiver(val listener : (NetworkInfo) -> Unit) : BroadcastReceiver() {
    override fun onReceive(context: Context, intent: Intent) {
    val con = context.getSystemService(ConnectivityManager::class.java)
    listener(con.activeNetworkInfo)
    }
    }
    

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26. class NetworkReceiver(val listener : (NetworkInfo) -> Unit) : BroadcastReceiver() {
    override fun onReceive(context: Context, intent: Intent) {
    val con = context.getSystemService(ConnectivityManager::class.java)
    listener(con.activeNetworkInfo)
    }
    }
    

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27. class MainActivity : AppCompatActivity() {
    private lateinit var networkReceiver : NetworkReceiver
    override fun onCreate(...) {
    networkReceiver = NetworkReceiver { // do something }
    val filter = IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION)
    registerReceiver(networkReceiver, filter)
    }
    override fun onDestroy() {
    unregisterReceiver(networkReceiver)
    }
    }
    

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28. class MainActivity : AppCompatActivity() {
    private lateinit var networkReceiver : NetworkReceiver
    override fun onCreate(...) {
    networkReceiver = NetworkReceiver { // do something }
    val filter = IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION)
    registerReceiver(networkReceiver, filter)
    }
    override fun onDestroy() {
    unregisterReceiver(networkReceiver)
    }
    }
    

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29. class MainActivity : AppCompatActivity() {
    private lateinit var networkReceiver : NetworkReceiver
    override fun onCreate(...) {
    networkReceiver = NetworkReceiver { // do something }
    val filter = IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION)
    registerReceiver(networkReceiver, filter)
    }
    override fun onDestroy() {
    unregisterReceiver(networkReceiver)
    }
    }
    

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30. class NetworkObserver(val owner : LifecycleOwner,
    private val context: Context,
    private val listener: (NetworkInfo) -> Unit)
    : LifecycleObserver {
    private val receiver = object : BroadcastReceiver() {
    ...
    }
    }
    

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31. class NetworkObserver(val owner : LifecycleOwner,
    private val context: Context,
    private val listener: (NetworkInfo) -> Unit)
    : LifecycleObserver {
    init {
    owner.lifecycle.addObserver(this)
    }
    private val receiver = object : BroadcastReceiver() {
    ...
    }
    }
    

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32. ...
    @OnLifecycleEvent(Lifecycle.Event.ON_CREATE)
    fun register() {
    val filter = IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION)
    context.registerReceiver(receiver, filter)
    }
    @OnLifecycleEvent(Lifecycle.Event.ON_DESTROY)
    fun unregister() {
    context.unregisterReceiver(receiver)
    }
    }
    

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33. class MainActivity : AppCompatActivity() {
    override fun onCreate(...) {
    NetworkObserver(this, this) {
    // do something
    }
    }
    }
    

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34. Observer Pattern
    vs
    Pub-Sub Pattern
    

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35. <>
    Subject
    

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36. <>
    Subject
    ConcreteSubject ConcreteSubject
    

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37. <>
    Subject
    ConcreteSubject ConcreteSubject
    <>
    Observer
    ConcreteObserve
    r
    ConcreteObserve
    r
    observe
    

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38. <>
    Subject
    ConcreteSubject ConcreteSubject
    <>
    Observer
    ConcreteObserve
    r
    ConcreteObserve
    r
    event
    notify
    

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43. LiveData
    

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45. Activity#0
    created
    onCreate
    onStart
    onResume
    onPause
    onStop
    onDestroy
    Device
    rotated
    Activity#1
    created
    Exception
    Call Web API
    

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46. LiveData
    addObserver
    

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47. LiveData
    Observer
    value
    

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48. LiveData
    Observer
    Lifecycle
    Owner
    

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49. Lifecycle
    Owner
    LiveData
    LifecycleBoundObserver
    Observer
    addObserver
    addObserver dispatch events
    active
    onChanged
    LiveData
    

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50. Lifecycle
    Owner
    LiveData
    LifecycleBoundObserver
    Observer
    addObserver
    addObserver dispatch events
    inactive
    onChanged
    LiveData
    

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51. Lifecycle
    Owner
    LiveData
    LifecycleBoundObserver
    Observer
    removeObserver
    addObserver dispatch events
    destroyed
    onChanged
    

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52. object CatRepository {
    private val _cat = MutableLiveData()
    fun loadCat(catId : Int) : LiveData {
    fetch(catId) { newCat -> _cat.postValue(newCat) }
    return _cat
    }
    }
    

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53. class CatActivity : AppCompatActivity() {
    override fun onCreate(...) {
    val catId = intent.getIntExtra("cat_id")
    CatRepository.loadCat(catId).observe(this,
    Observer { cat -> showCat(cat)})
    }
    }
    

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54. class CatActivity : AppCompatActivity() {
    override fun onCreate(...) {
    ...
    val relatedCatsModule = RelatedCatsModuleAdapter { clicked ->
    val intent = Intent(this, CatActivity::class.java)
    intent.putExtra("cat_id", clicked.id)
    startActivity(intent)
    }
    }
    }
    

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55. ViewModels
    

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57. Activity#0
    created
    onCreate
    onStart
    onResume
    Call Web API
    

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58. Activity#0
    created
    onCreate
    onStart
    onResume
    onPause
    onStop
    onDestroy
    Device
    rotated
    Activity#1
    created
    Call Web API
    onCreate
    Call Web API
    

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59. ViewModel
    Provider
    ViewModel
    Store
    Activity/Fragment
    request
    get
    null
    ViewModel
    

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60. return
    ViewModel
    Provider
    ViewModel
    Store
    Activity/Fragment
    request
    get
    null
    put
    ViewModel
    ViewModel
    

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61. ViewModel
    Store
    Activity/Fragment
    ViewModel
    in NonConfigurationInstance
    

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63. public class FragmentActivity extends ComponentActivity ... {
    @Override public final Object onRetainNonConfigurationInstance() {
    ...
    NonConfigurationInstances nci = new NonConfigurationInstances();
    nci.custom = custom;
    nci.viewModelStore = mViewModelStore;
    nci.fragments = fragments;
    return nci;
    }
    

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64. public class FragmentActivity extends ComponentActivity ... {
    @Override protected void onCreate(...) {
    ...
    NonConfigurationInstances nc = (NonConfigurationInstances) getLastNonConfigurationInstance();
    if (nc != null && nc.viewModelStore != null && mViewModelStore == null) {
    mViewModelStore = nc.viewModelStore;
    }
    

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66. Repository
    Model
    Repository
    

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67. Repository
    Model
    Repository
    Activity / Fragment
    

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68. Repository
    Model
    

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69. private val _cat = MutableLiveData>()
    fun updateCat(new: Cat) {
    val currentCats = _cat.value ?: return
    val updatedCats = currentCats.toMutableList()
    .map { old -> if(old.id == new.id) new else old }
    _cat.postValue(updatedCats)
    // update storage and web service
    ...
    }
    

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70. private val _cat = MutableLiveData>()
    fun updateCat(new: Cat) {
    val currentCats = _cat.value ?: return
    val updatedCats = currentCats.toMutableList()
    .map { old -> if(old.id == new.id) new else old }
    _cat.postValue(updatedCats)
    // update storage and web service
    ...
    }
    

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71. private val _cat = MutableLiveData>()
    fun updateCat(new: Cat) {
    val currentCats = _cat.value ?: return
    val updatedCats = currentCats.toMutableList()
    .map { old -> if(old.id == new.id) new else old }
    _cat.postValue(updatedCats)
    // update storage and web service
    ...
    }
    

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72. @Entity
    data class Cat(
    @PrimaryKey(autoGenerate = true)
    val id: Int = 0,
    val name: String,
    val age: Int,
    val description: String,
    val loved: Boolean
    )
    

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73. @Dao
    interface CatDao {
    @Query("SELECT * from Cat")
    fun loadCats() : LiveData>
    @Update
    fun update(cat: Cat)
    }
    

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74. @Database(entities = [Cat::class], version = 1)
    abstract class CatDatabase : RoomDatabase() {
    abstract fun catDao() : CatDao
    }
    

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75. fun getCatDatabase(context: Context) =
    Room.databaseBuilder(context, CatDatabase::class.java, "catDB").build()
    

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76. fun updateCat(new: Cat) {
    // update logic here
    catDao.updateCat(new)
    catService.updateData(new)
    }
    

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77. Cat Database
    Cat table
    room_master_table
    Id, identity_hash
    

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78. Cat Database
    Cat table
    room_master_table
    Id, identity_hash
    room_table_modification_log
    InvalidationTracker
    Updated?
    Version, table_id
    onInvalidated
    Observer
    trigger
    Oh, yes!
    

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79. Cat Database
    Cat table
    room_master_table
    Id, identity_hash
    room_table_modification_log
    InvalidationTracker
    Version, table_id
    Observer
    ComputeLiveDat
    a
    addObserver
    query
    Cat Dao
    

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80. Cat Database
    Cat table
    room_master_table
    Id, identity_hash
    room_table_modification_log
    InvalidationTracker
    Version, table_id
    Observer
    Cat Dao
    ComputeLiveDat
    a
    addObserver
    query
    onInvalidated
    

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81. Why use Paging library?
    

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82. Repository
    ViewModel
    Activity /
    Fragment
    What do
    I display?
    I need cats
    Give us
    ALL Cats
    OK,
    1,000,000
    cats here.
    Here you are
    Show this
    1,000,000
    cats
    ¯\_(π)_/¯
    

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83. PagedList DataSource
    

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84. PagedList DataSource
    

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85. PagedList DataSource
    DataSource.Factory
    

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86. PagedList DataSource
    DataSource.Factory
    invalidate
    

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87. PagedList DataSource
    DataSource.Factory
    

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88. View ViewModel Repository
    DataSource.Factory
    LiveData>
    Room
    LivePagedListBuilder
    

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89. View
    Observer
    ViewModel Repository
    DataSource.Factory
    LiveData>
    Room
    LivePagedListBuilder
    LivePagedListBuilder
    DataSource.Factory
    

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90. View ViewModel Repository
    DataSource.Factory
    LiveData>
    PagedListAdapter
    Room
    Observer LivePagedListBuilder
    AsyncPagedListDiffer
    

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91. View ViewModel Repository
    DataSource.Factory
    LiveData>
    PagedListAdapter
    Room
    Observer LivePagedListBuilder
    AsyncPagedListDiffer
    

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92. public abstract class PagedListAdapter ... {
    final AsyncPagedListDiffer mDiffer;
    @Nullable protected T getItem(int position) {
    return mDiffer.getItem(position);
    }
    }
    

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93. public class AsyncPagedListDiffer {
    ...
    public T getItem(int index) {
    ...
    mPagedList.loadAround(index);
    return mPagedList.get(index);
    }
    }
    

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94. public abstract class PagedList extends AbstractList {
    ...
    public void loadAround(int index) {
    ...
    loadAroundInternal(index);
    ...
    }
    }
    

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95. class ContiguousPagedList extends PagedList ... {
    protected void loadAroundInternal(int index) {
    int appendItems = getAppendItemsRequested(...);
    ...
    mAppendItemsRequested = Math.max(...);
    if (mAppendItemsRequested > 0) {
    scheduleAppend();
    }
    }
    

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96. Summary
    

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