No content

forLoopUyo Maiden Edition New Android Architecture Component with MVVM 

+Nsikak Thompson Lead Android Developer @StartHubTech Passionate about good UI designs @thompson_nsikak NsikakTopdown 

Scope ● Introduction ● Room Library ● LiveData ● LifeCycle ● ViewModel 

What Troubles Us MVP MVC MVVM Clean 

Iyamiiii !!! 

Android Architecture Component collection of libraries that help you design robust, Android Architecture Component collection of libraries that help you design robust, testable, and maintainable apps. 

Core Components of the Architecture Libraries - Room : An abstraction layer over SQLite which provided object mapping similar to OrmLite. - LiveData: data holder class that keeps a value and allows this value to be observed. - - LifeCycle: it contains information about the lifecycle state of a component such as Activities and fragments - - ViewModel: store and manage UI-related data so that the data survives configuration changes such as screen rotations.. 

Why Use this architecture components? - This framework aims to reduce the amount of boilerplate and repetitive code - Helps you focus on your business Logic - Easy to Test 

Adding architecture components to your Android App 

Demo App 

No content

Adding architecture components to your Android App //For LifeCycle, ViewModel and LiveData compile "android.arch.lifecycle:runtime:1.0.0-alpha5" compile "android.arch.lifecycle:extensions:1.0.0-alpha5" annotationProcessor "android.arch.lifecycle:compiler:1.0.0-alpha5" //For Room compile "android.arch.persistence.room:runtime:1.0.0-alpha5" annotationProcessor "android.arch.persistence.room:compiler:1.0.0-alpha5" 

Database Libraries for Android ROOM Our Focus 

Room 

What is Room? Room - An abstraction layer over SQLite which provided object mapping similar to OrmLite. - The core framework provides built-in support for working with raw SQL content. 

Getting Started with Room 

Create Entity @Entity(tableName = TABLE_NAME) public class Task { public static final String TABLE_NAME = "task"; public static final String TITLE = "title"; public static final String DESCRIPTION = "description"; @PrimaryKey(autoGenerate = true) private int id; @ColumnInfo(name = TITLE) private String title; @ColumnInfo(name = DESCRIPTION) private String description; //getter and setters 

Create Data Access Object (DAO) @Dao public interface TaskDao { @Query("SELECT * FROM " + Task.TABLE_NAME ) LiveData> getAllTask(); @Insert(onConflict = REPLACE) void addTask(Task task); @Delete void deleteTask(Task task); @Update(onConflict = REPLACE) void updateTask(Task task); 

Finally Create the Database @Database(entities = {Task.class}, version = 1) public abstract class TaskDatabase extends RoomDatabase { public abstract TaskDao taskDao(); } Room.databaseBuilder(context.getApplicationContext(), TaskDatabase.class, "task_db").build(); 

LiveData 

What is LiveData? - LiveData allows you to observe changes to data across multiple components of your app without creating explicit, and rigid dependency paths between them. - data holder class that keeps a value and allows this value to be observed. 

Get LiveData and Observe @Dao public interface TaskDao { @Query("SELECT * FROM " + Task.TABLE_NAME ) LiveData> getAllTask(); taskDao.getTasks().observe(this, tasks ->{ //Update UI taskAdapter.setItems(tasks); recyclerView.setAdapter(taskAdapter); }); 

ViewModel 

ViewModel - It is part of the MVVM architecture - stores and manage UI-related data - survives configuration changes such as screen rotations 

The lifecycle of a ViewModel - The ViewModel stays in memory until the LifeCycle it’s scoped to goes away permanently - retain data across configuration changes - ViewModel outlives the specific Activity or Fragment instances. 

Returning and Observing your ViewModel @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_task_list, container, false); //Get our VM taskListViewModel = ViewModelProviders.of(this, newTaskFactory(appController)).get(TaskListViewModel.class); //Observing taskListViewModel.getTasks().observe(this, tasks ->{ taskAdapter.setItems(tasks); recyclerView.setAdapter(taskAdapter); }); 

Summary ● Room – A SQLite object mapper. Very similar to other libraries such as ORMlite or greenDAO. It uses SQL while still allowing compile time guarantees on the queries. ● LiveData – A Lifecycle aware observable core component. ● ViewModel – The communication points with the rest of the application for Activities / Fragments. They are UI code free and outlive the activity or fragment. ● Lifecycle – A core part of the Architecture components, it contains information about the lifecycle state of a component (for instance an Activity). 

Questions??? goo.gl/slides/vxgqgb Github : https://goo.gl/TiX7tQ 

Thank You @thompson_nsikak NsikakTopdown