Inside Jetpack

Transcript

1. Inside Jetpack Architecture Components Hiroyuki Mori @moridroid
2. • Started as a Venture between Softbank and Yahoo • One of biggest search in Japan • Not a part of big
3. What & Why Architecture Components
5. View View Controller Application Logic Network Persistent Model onSendClick sendComment
6. onSendClick sendComment View View Controller Application Logic Network Persistent Model
7. View View Controller Application Logic Network Persistent Model
8. View View Controller Application Logic Network Persistent Model subscribe
9. View View Controller Application Logic Network Persistent Model onSendClick sendComment
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19. Lifcycle problems
20. In early days
21. Steve Pomeroy https://github.com/xxv/android-lifecycle CC-BY-SA 4.0 Today
22. LifecycleObserver
23. Android System NetworkReceiver Network state Foo Activity observe observe notify notify state changed
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) } }
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) } }
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) } }
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) } }
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) } }
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) } }
30. class NetworkObserver(val owner : LifecycleOwner, private val context: Context, private val listener: (NetworkInfo) -> Unit) : LifecycleObserver { private val receiver = object : BroadcastReceiver() { ... } }
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() { ... } }
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) } }
33. class MainActivity : AppCompatActivity() { override fun onCreate(...) { NetworkObserver(this, this) { // do something } } }
34. Observer Pattern vs Pub-Sub Pattern
35. <<interface>> Subject
36. <<interface>> Subject ConcreteSubject ConcreteSubject
37. <<interface>> Subject ConcreteSubject ConcreteSubject <<interface>> Observer ConcreteObserve r ConcreteObserve r observe
38. <<interface>> Subject ConcreteSubject ConcreteSubject <<interface>> Observer ConcreteObserve r ConcreteObserve r event notify
43. LiveData
45. Activity#0 created onCreate onStart onResume onPause onStop onDestroy Device rotated Activity#1 created Exception Call Web API
46. LiveData addObserver
47. LiveData Observer value
48. LiveData Observer Lifecycle Owner
49. Lifecycle Owner LiveData LifecycleBoundObserver Observer addObserver addObserver dispatch events active onChanged LiveData
50. Lifecycle Owner LiveData LifecycleBoundObserver Observer addObserver addObserver dispatch events inactive onChanged LiveData
51. Lifecycle Owner LiveData LifecycleBoundObserver Observer removeObserver addObserver dispatch events destroyed onChanged
52. object CatRepository { private val _cat = MutableLiveData<Cat>() fun loadCat(catId : Int) : LiveData<Cat> { fetch(catId) { newCat -> _cat.postValue(newCat) } return _cat } }
53. class CatActivity : AppCompatActivity() { override fun onCreate(...) { val catId = intent.getIntExtra("cat_id") CatRepository.loadCat(catId).observe(this, Observer { cat -> showCat(cat)}) } }
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) } } }
55. ViewModels
57. Activity#0 created onCreate onStart onResume Call Web API
58. Activity#0 created onCreate onStart onResume onPause onStop onDestroy Device rotated Activity#1 created Call Web API onCreate Call Web API
59. ViewModel Provider ViewModel Store Activity/Fragment request get null ViewModel
60. return ViewModel Provider ViewModel Store Activity/Fragment request get null put ViewModel ViewModel
61. ViewModel Store Activity/Fragment ViewModel in NonConfigurationInstance
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; }
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; }
66. Repository Model Repository
67. Repository Model Repository Activity / Fragment
68. Repository Model
69. private val _cat = MutableLiveData<List<Cat>>() 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 ... }
70. private val _cat = MutableLiveData<List<Cat>>() 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 ... }
71. private val _cat = MutableLiveData<List<Cat>>() 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 ... }
72. @Entity data class Cat( @PrimaryKey(autoGenerate = true) val id: Int = 0, val name: String, val age: Int, val description: String, val loved: Boolean )
73. @Dao interface CatDao { @Query("SELECT * from Cat") fun loadCats() : LiveData<List<Cat>> @Update fun update(cat: Cat) }
74. @Database(entities = [Cat::class], version = 1) abstract class CatDatabase : RoomDatabase() { abstract fun catDao() : CatDao }
75. fun getCatDatabase(context: Context) = Room.databaseBuilder(context, CatDatabase::class.java, "catDB").build()
76. fun updateCat(new: Cat) { // update logic here catDao.updateCat(new) catService.updateData(new) }
77. Cat Database Cat table room_master_table Id, identity_hash
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!
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
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
81. Why use Paging library?
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)_/¯
83. PagedList DataSource
84. PagedList DataSource
85. PagedList DataSource DataSource.Factory
86. PagedList DataSource DataSource.Factory invalidate
87. PagedList DataSource DataSource.Factory
88. View ViewModel Repository DataSource.Factory LiveData<PagedList > Room LivePagedListBuilder
89. View Observer ViewModel Repository DataSource.Factory LiveData<PagedList > Room LivePagedListBuilder LivePagedListBuilder DataSource.Factory
90. View ViewModel Repository DataSource.Factory LiveData<PagedList > PagedListAdapter Room Observer LivePagedListBuilder AsyncPagedListDiffer
91. View ViewModel Repository DataSource.Factory LiveData<PagedList > PagedListAdapter Room Observer LivePagedListBuilder AsyncPagedListDiffer
92. public abstract class PagedListAdapter<T, VH> ... { final AsyncPagedListDiffer<T> mDiffer; @Nullable protected T getItem(int position) { return mDiffer.getItem(position); } }
93. public class AsyncPagedListDiffer<T> { ... public T getItem(int index) { ... mPagedList.loadAround(index); return mPagedList.get(index); } }
94. public abstract class PagedList<T> extends AbstractList<T> { ... public void loadAround(int index) { ... loadAroundInternal(index); ... } }
95. class ContiguousPagedList<K, V> extends PagedList<V> ... { protected void loadAroundInternal(int index) { int appendItems = getAppendItemsRequested(...); ... mAppendItemsRequested = Math.max(...); if (mAppendItemsRequested > 0) { scheduleAppend(); } }
96. Summary