Jetpack
Jetpack 是一个由多个库组成的套件，可帮忙开发者遵循最佳做法，缩小样板代码并编写可在各种 Android 版本和设施中统一运行的代码，让开发者精力集中编写重要的代码。
Android Architecture Component (AAC)。
官网举荐架构
请留神，每个组件仅依赖于其下一级的组件。例如，Activity 和 Fragment 仅依赖于视图模型。存储区是惟一依赖于其余多个类的类；在本例中，存储区依赖于持久性数据模型和近程后端数据源。
MVVM
MVVM即Model - View - ViewModel的缩写，它的呈现是为了将图形界面与业务逻辑，数据模型进行解耦。
MVVM也是Google推崇的一种Android我的项目架构模型。
之前学习的Jetpack组建，大部分都是为了可能更好地架构MVVM应用程序而设计的。
API接口
接口：https://api.github.com/users/...
工程构造
bean：实体类。
api：网络申请接口。
repository：仓储层。用于寄存Room数据，网络数据，本地数据等。
viewmodel：从仓储层获取数据，不须要关怀数据起源。
view：Activity，Fragment和布局文件，用会用到DataBinding组件
dao：Room数据库操作
application：实例化全局文件和获取全局上下文。
bindingAdapter：放一些
增加依赖
implementation 'androidx.swiperefreshlayout:swiperefreshlayout:1.1.0'implementation 'de.hdodenhof:circleimageview:3.0.1'搭建我的项目
通过获取GitHub API获取个人信息进行展现。
1. 定义User实体类
@Entity(tableName = "user")data class User( @PrimaryKey @ColumnInfo(name = "id", typeAffinity = ColumnInfo.INTEGER) var id: Int, @ColumnInfo(name = "login", typeAffinity = ColumnInfo.TEXT) var login: String, @ColumnInfo(name = "name", typeAffinity = ColumnInfo.TEXT) var name: String?, @ColumnInfo(name = "avatar_url", typeAffinity = ColumnInfo.TEXT) @SerializedName("avatar_url")var avatar: String?, @ColumnInfo(name = "blog", typeAffinity = ColumnInfo.TEXT) var blog: String, @ColumnInfo(name = "company", typeAffinity = ColumnInfo.TEXT) var company: String?, @ColumnInfo(name = "bio", typeAffinity = ColumnInfo.TEXT) var bio: String?, @ColumnInfo(name = "location", typeAffinity = ColumnInfo.TEXT) var location: String?, @ColumnInfo(name = "htmlUrl", typeAffinity = ColumnInfo.TEXT) @SerializedName("html_url") var htmlUrl: String?)```####2. 定义Dao类```@Daointerface UserDao { @Insert(onConflict = OnConflictStrategy.REPLACE) fun insertUser(user: User) @Delete fun deleteUser(user: User) @Query("select * from user where login =:name") fun getUserByName(name: String): LiveData<User>}```####3. 定义DataBase类```@Database(entities = [User::class], version =7)abstract class AppDatabase : RoomDatabase() { abstract fun userDao(): UserDao companion object { private var instance: AppDatabase? = null @Synchronized fun getDatabase(context: Context): AppDatabase { instance?.let { return it } return Room.databaseBuilder( context.applicationContext, AppDatabase::class.java, "user_db" ).fallbackToDestructiveMigration().build().apply { instance = this } } }}4. 定义API接口interface Api { @GET("users/{userName}") fun getUser(@Path("userName") userName: String): Call<User>}5. 定义Retrofit拜访网络object RetrofitClient { private const val BASE_URL = "https://api.github.com/" var retrofit: Retrofit init { retrofit = Retrofit.Builder().baseUrl(BASE_URL).addConverterFactory(GsonConverterFactory.create()) .build() } fun getApi(): Api? { return retrofit.create(Api::class.java) }}6. 定义Application类class MyApplication : Application() { companion object { lateinit var context: Context } override fun onCreate() { super.onCreate() context = applicationContext }}7. 定义Repositoryobject UserRepository { var userDao: UserDao = AppDatabase.getDatabase(MyApplication.context).userDao() fun getUser(name: String): LiveData<User> { refresh(name) return userDao.getUserByName(name) } fun refresh(name: String) { RetrofitClient.getApi()?.getUser(name)?.enqueue(object : Callback<User> { override fun onResponse(call: Call<User>, response: Response<User>) { if (response.body() != null) { insertUser(response.body()!!) } } override fun onFailure(call: Call<User>, t: Throwable) { Log.d("UserRepository", "onFailure$t") } }) } fun insertUser(user: User) { thread { userDao.insertUser(user) } }}8. 定义ViewModelclass MvvmViewModel : ViewModel() { val userName = "yaoxin521123" fun getUser() = UserRepository.getUser(userName) fun refresh() = UserRepository.refresh(userName)}9. 绘制xml<?xml version="1.0" encoding="utf-8"?><layout xmlns:app="http://schemas.android.com/apk/res-auto"> <data> <variable name="user" type="com.yx.androidseniorpreparetest.eighth.bean.User" /> </data> <androidx.swiperefreshlayout.widget.SwipeRefreshLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/srl_SwipeRefreshLayout" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".eighth.MvvmActivity"> <LinearLayout android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <de.hdodenhof.circleimageview.CircleImageView android:layout_width="95dp" android:layout_height="95dp" android:layout_gravity="center" android:layout_marginTop="20dp" app:image="@{user.avatar}" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:layout_marginTop="20dp" android:text="@{user.name}" android:textColor="#000000" android:textSize="20sp" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:layout_marginTop="20dp" android:text="@{user.login}" android:textColor="#000000" android:textSize="20sp" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:layout_marginTop="20dp" android:text="@{user.blog}" android:textColor="#000000" android:textSize="20sp" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:layout_marginTop="20dp" android:text="@{user.company}" android:textColor="#000000" android:textSize="20sp" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:layout_marginTop="20dp" android:text="@{user.bio}" android:textColor="#000000" android:textSize="20sp" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:layout_marginTop="20dp" android:text="@{user.location}" android:textColor="#000000" android:textSize="20sp" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:layout_marginTop="20dp" android:text="@{user.htmlUrl}" android:textColor="#000000" android:textSize="20sp" /> </LinearLayout> </androidx.swiperefreshlayout.widget.SwipeRefreshLayout</layout>10. 在Activity触发事件class MvvmActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) val binding = DataBindingUtil.setContentView<ActivityMvvmBinding>(this, R.layout.activity_mvvm) val viewModel = ViewModelProviders.of(this).get(MvvmViewModel::class.java) viewModel.getUser().observe(this, { if (it != null) { binding.user = it } }) binding.srlSwipeRefreshLayout.setOnRefreshListener { viewModel.refresh() binding.srlSwipeRefreshLayout.isRefreshing = false } }}11. 定义BindingAapterclass BindingAdapter { companion object { @JvmStatic @BindingAdapter(value = ["image", "defaultImageResource"], requireAll = false) fun setImage(imageView: ImageView, imageUrl: String?, imageResource: Int) { if (!TextUtils.isEmpty(imageUrl)) { Picasso.get() .load(imageUrl) .placeholder(R.drawable.ic_launcher_background) .error(R.drawable.ic_launcher_background) .into(imageView) } else { imageView.setImageResource(imageResource) } } }}结语：后续会继续更新哦，喜爱的话点赞关注一下吧。
相干视频
【Android进阶】jetpack教程