[Devfest '17] Architecture Components

Get to know the new Architecture Components released by Google in I/O'17

Gave this talk for GDG Cloud Vancouver Devfest'17
Animated GIF version: https://goo.gl/dVj63L

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26. // Project’s root build.gradle allprojects { repositories { jcenter() maven { url 'https://maven.google.com' } // or use google() } } @nisrulz #devfest17
27. // Project’s root build.gradle allprojects { repositories { jcenter() maven { url 'https://maven.google.com' } // or use google() } } @nisrulz #devfest17
28. // app’s build.gradle // For Lifecycles, LiveData, and ViewModel, add: implementation "android.arch.lifecycle:runtime:1.0.0" implementation "android.arch.lifecycle:extensions:1.0.0-beta2" annotationProcessor "android.arch.lifecycle:compiler:1.0.0-beta2" @nisrulz #devfest17
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30. class MyLocationListener { public MyLocationListener(Context context, Callback callback) { // ... } void start() { // connect to system location service } void stop() { // disconnect from system location service } } @nisrulz #devfest17
31. class MyLocationListener { public MyLocationListener(Context context, Callback callback) { // ... } void start() { // connect to system location service } void stop() { // disconnect from system location service } } @nisrulz #devfest17
32. class MyActivity extends AppCompatActivity { private MyLocationListener myLocationListener; public void onCreate(...) { myLocationListener = new MyLocationListener(this, (location) -> { // update UI }); } } @nisrulz #devfest17
33. class MyActivity extends AppCompatActivity { private MyLocationListener myLocationListener; public void onCreate(...) { myLocationListener = new MyLocationListener(this, (location) -> { // update UI }); } } @nisrulz #devfest17
34. class MyActivity extends AppCompatActivity { // .. public void onStart() { super.onStart(); myLocationListener.start(); } public void onStop() { super.onStop(); myLocationListener.stop(); } } @nisrulz #devfest17
35. class MyActivity extends AppCompatActivity { // .. public void onStart() { super.onStart(); myLocationListener.start(); } public void onStop() { super.onStop(); myLocationListener.stop(); } } @nisrulz #devfest17
36. class MyActivity extends AppCompatActivity { //... public void onStart() { super.onStart(); Util.checkUserStatus(result -> { // what if this callback is invoked AFTER activity is stopped? if (result) { myLocationListener.start(); } }); } // onStop() } @nisrulz #devfest17
37. class MyActivity extends AppCompatActivity { //... public void onStart() { super.onStart(); Util.checkUserStatus(result -> { // what if this callback is invoked AFTER activity is stopped? if (result) { myLocationListener.start(); } }); } // onStop() } @nisrulz #devfest17
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39. Lifecycle Owner Class with lifecycle i.e Activity & Fragments @nisrulz #devfest17
40. Lifecycle Owner Class with lifecycle i.e Activity & Fragments Lifecycle Observer Class that observe lifecycle @nisrulz #devfest17
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42. public class MyLocationListener implements LifecycleObserver { public MyLocationListener(Context context, Lifecycle lifecycle, Callback callback) { // ... lifecycle.addObserver(this); } } @nisrulz #devfest17
43. public class MyLocationListener implements LifecycleObserver { public MyLocationListener(Context context, Lifecycle lifecycle, Callback callback) { // ... lifecycle.addObserver(this); } } @nisrulz #devfest17
44. public class MyLocationListener implements LifecycleObserver { // ... @OnLifecycleEvent(Lifecycle.Event.ON_START) public void start() { // connect to system location service } @OnLifecycleEvent(Lifecycle.Event.ON_STOP) public void stop() { // disconnect from system location service } } @nisrulz #devfest17
45. public class MyLocationListener implements LifecycleObserver { // ... @OnLifecycleEvent(Lifecycle.Event.ON_START) public void start() { // connect to system location service } @OnLifecycleEvent(Lifecycle.Event.ON_STOP) public void stop() { // disconnect from system location service } } @nisrulz #devfest17
46. public class MyLocationListener implements LifecycleObserver { // ... @OnLifecycleEvent(Lifecycle.Event.ON_DESTROY) public void cleanup() { lifecycle.removeObserver(this); } } @nisrulz #devfest17
47. public class MyLocationListener implements LifecycleObserver { // ... @OnLifecycleEvent(Lifecycle.Event.ON_DESTROY) public void cleanup() { lifecycle.removeObserver(this); } } @nisrulz #devfest17
48. class MyActivity extends AppCompatActivity { private MyLocationListener myLocationListener; public void onCreate() { myLocationListener = new MyLocationListener(this, getLifecycle(), location -> { //update UI }); Util.checkUserStatus(result -> { //... }); } } @nisrulz #devfest17
49. class MyActivity extends AppCompatActivity { private MyLocationListener myLocationListener; public void onCreate() { myLocationListener = new MyLocationListener(this, getLifecycle(), location -> { //update UI }); Util.checkUserStatus(result -> { //... }); } } @nisrulz #devfest17
50. class MyActivity extends AppCompatActivity { private MyLocationListener myLocationListener; public void onCreate() { myLocationListener = new MyLocationListener(this, getLifecycle(), location -> { //update UI }); Util.checkUserStatus(result -> { //... }); } } @nisrulz #devfest17
51. class MyActivity extends AppCompatActivity { private MyLocationListener myLocationListener; public void onCreate() { myLocationListener = new MyLocationListener(this, getLifecycle(), location -> { //update UI }); Util.checkUserStatus(result -> { //... }); } } @nisrulz #devfest17
52. As of release of Support Library v26.1.0 @nisrulz #devfest17
53. As of release of Support Library v26.1.0 “Fragment and FragmentActivity (the base class for AppCompatActivity) now implement the LifecycleOwner interface from Architecture Components” @nisrulz #devfest17
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63. class LocationManager extends LiveData<Location>{ // ... } @nisrulz #devfest17
64. class LocationManager extends LiveData<Location>{ @override protected void onActive(){ super.onActive(); // connect to location } @override protected void onInactive(){ super.onInactive(); // disconnect from location } } @nisrulz #devfest17
65. class LocationManager extends LiveData<Location>{ @override protected void onActive(){ super.onActive(); // connect to location } @override protected void onInactive(){ super.onInactive(); // disconnect from location } } @nisrulz #devfest17
66. class MyActivity extends AppCompatActivity { public void onCreate(...) { LocationManager.getInstance().observe(this, location -> { //Location Changed }) } } @nisrulz #devfest17
67. class MyActivity extends AppCompatActivity { public void onCreate(...) { LocationManager.getInstance().observe(this, location -> { //Location Changed }) } } @nisrulz #devfest17
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70. @nisrulz #devfest17 It is the VM in MVVM architecture
71. @nisrulz #devfest17 It is the VM in MVVM architecture A simple class to store and manage ui-related data
72. @nisrulz #devfest17 It is the VM in MVVM architecture A simple class to store and manage ui-related data Data survives configuration changes such as screen rotation
73. @nisrulz #devfest17 It is the VM in MVVM architecture A simple class to store and manage ui-related data Data survives configuration changes such as screen rotation No memory leaks (no references to activity or fragment or views)
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75. @nisrulz #devfest17 public class MyViewModel extends ViewModel { private MutableLiveData<List<User>> users; public LiveData<List<User>> getUsers() { if (users == null) { users = new MutableLiveData<List<Users>>(); loadUsers(); } return users; } private void loadUsers() { // do async operation to fetch users } }
76. @nisrulz #devfest17 public class MyViewModel extends ViewModel { private MutableLiveData<List<User>> users; public LiveData<List<User>> getUsers() { if (users == null) { users = new MutableLiveData<List<Users>>(); loadUsers(); } return users; } private void loadUsers() { // do async operation to fetch users } }
77. @nisrulz #devfest17 public class MyActivity extends AppCompatActivity { public void onCreate(Bundle savedInstanceState) { MyViewModel model = ViewModelProviders .of(this) .get(MyViewModel.class); model.getUsers().observe(this, users -> { // update UI }); } }
78. @nisrulz #devfest17 public class MyActivity extends AppCompatActivity { public void onCreate(Bundle savedInstanceState) { MyViewModel model = ViewModelProviders .of(this) .get(MyViewModel.class); model.getUsers().observe(this, users -> { // update UI }); } }
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80. @nisrulz #devfest17 ViewModels - provide a convenient way to retain data across configuration changes - they are not persisted if the application is killed by the operating system.
81. @nisrulz #devfest17 ViewModels - provide a convenient way to retain data across configuration changes - they are not persisted if the application is killed by the operating system. SavedInstanceState - stores data, usually ID - they are saved in system process memory, OS limits the amount
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95. // app’s build.gradle // For Room, add: implementation "android.arch.persistence.room:runtime:1.0.0-beta2" annotationProcessor "android.arch.persistence.room:compiler:1.0.0-beta2" @nisrulz #devfest17
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97. @nisrulz #devfest17 @Entity public class User { @PrimaryKey private int uid; @ColumnInfo(name = "first_name") private String firstName; @ColumnInfo(name = "last_name") private String lastName; // Getters and setters are ignored for brevity, // but they're required for Room to work. }
98. @nisrulz #devfest17 @Entity public class User { @PrimaryKey private int uid; @ColumnInfo(name = "first_name") private String firstName; @ColumnInfo(name = "last_name") private String lastName; // Getters and setters are ignored for brevity, // but they're required for Room to work. }
99. @nisrulz #devfest17 @Dao public interface UserDao { @Query("SELECT * FROM user") List<User> getAll(); @Insert void insertAll(User... users); @Delete void delete(User user); }
100. @nisrulz #devfest17 @Dao public interface UserDao { @Query("SELECT * FROM user") List<User> getAll(); @Insert void insertAll(User... users); @Delete void delete(User user); }
101. @nisrulz #devfest17 @Dao public interface UserDao { @Query("SELECT * FROM user") List<User> getAll(); @Insert void insertAll(User... users); @Delete void delete(User user); }
102. @nisrulz #devfest17 @Dao public interface UserDao { @Query("SELECT * FROM user") List<User> getAll(); @Insert void insertAll(User... users); @Delete void delete(User user); }
103. @nisrulz #devfest17 @Database(entities = {User.class}, version = 1) public abstract class AppDatabase extends RoomDatabase { public abstract UserDao userDao(); }
104. @nisrulz #devfest17 @Database(entities = {User.class}, version = 1) public abstract class AppDatabase extends RoomDatabase { public abstract UserDao userDao(); }
105. @nisrulz #devfest17 @Database(entities = {User.class}, version = 1) public abstract class AppDatabase extends RoomDatabase { public abstract UserDao userDao(); }
106. @nisrulz #devfest17 @Database(entities = {User.class}, version = 1) public abstract class AppDatabase extends RoomDatabase { public abstract UserDao userDao(); }
107. @nisrulz #devfest17 @Database(entities = {User.class}, version = 1) public abstract class AppDatabase extends RoomDatabase { // .. private static AppDatabase INSTANCE; public static AppDatabase getDatabase(Context context) { if (INSTANCE == null) { INSTANCE= Room .databaseBuilder(getApplicationContext(), AppDatabase.class, "db_name") .build(); } return INSTANCE; } }
108. @nisrulz #devfest17 @Database(entities = {User.class}, version = 1) public abstract class AppDatabase extends RoomDatabase { // .. private static AppDatabase INSTANCE; public static AppDatabase getDatabase(Context context) { if (INSTANCE == null) { INSTANCE= Room .databaseBuilder(getApplicationContext(), AppDatabase.class, "db_name") .build(); } return INSTANCE; } }
109. @nisrulz #devfest17 // .. INSTANCE= Room .databaseBuilder(getApplicationContext(), AppDatabase.class, "db_name") .build();
110. @nisrulz #devfest17 // Get db AppDatabase appDatabase = AppDatabase .getDatabase(application); // Get data from db using the DAO List<User> userList = appDatabase .userDao() .getAll();
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112. @nisrulz #devfest17 Compile time SQL statement verification
113. @nisrulz #devfest17 Compile time SQL statement verification Testable
114. @nisrulz #devfest17 Compile time SQL statement verification Testable Support for RxJava 2
115. @nisrulz #devfest17 Compile time SQL statement verification Testable Support for RxJava 2 SQLite data relationship supported
116. @nisrulz #devfest17 Compile time SQL statement verification Testable Support for RxJava 2 SQLite data relationship supported Easily define multiple indexes to improve query performance
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118. @nisrulz #devfest17 @Dao public interface UserDao { @Query("SELECT * FROM user") List<User> getAll(); @Insert void insertAll(User... users); @Delete void delete(User user); }
119. @nisrulz #devfest17 @Dao public interface UserDao { @Query("SELECT * FROM user") LiveData<List<User>> getAll(); @Insert void insertAll(User... users); @Delete void delete(User user); }
120. @nisrulz #devfest17 @Dao public interface UserDao { @Query("SELECT * FROM user") LiveData<List<User>> getAll(); @Insert void insertAll(User... users); @Delete void delete(User user); }
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123. @nisrulz #devfest17 Data takes time to load
124. @nisrulz #devfest17 Data takes time to load Performance lag
125. @nisrulz #devfest17 Data takes time to load Performance lag Too much memory wasted
126. @nisrulz #devfest17 Gradually load information as needed from a data source, without overloading the device or waiting too long for a big database query.
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129. // app’s build.gradle // For Paging, add: implementation "android.arch.paging:runtime:1.0.0-alpha3" @nisrulz #devfest17
130. @nisrulz #devfest17 // If you use Room lib to manage your data @Query("select * from users WHERE age > :age order by name DESC, id ASC") TiledDataSource<User> usersOlderThan(int age);
131. @nisrulz #devfest17 Loads data from a DataSource. You can configure how much data - is loaded at a time - should be prefetched (minimizing the amount of time your users have to wait for data to be loaded)
132. @nisrulz #devfest17 Implementation of RecyclerView.Adapter that presents data from a PagedLi
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