前面我们使用Java来运用JetPack中的一系列组件，又使用kotlin运用这些组件实现了一系列功能：
- kotlin--Flow文件下载
- kotlin--Flow结合Room运用
- kotlin--Flow结合retrofit运用
- kotlin--StateFlow运用
- kotlin--SharedFlow运用
接着，Jetpack的Paging3中，我们使用的语言是kotlin，相信通过这些项目的对比，你就能发现koltin取代Java的理由了，kotlin拥有更好的扩展性，更高的性能，更简洁的代码，更好的Jetpack组件支持，如果你还对kotlin不熟悉，那么可以查阅我的kotlin专题博客，在此也要感谢动脑学院Jason老师的辛勤付出，动脑学院在B站上也有投稿koltin基础的视频，通过视频可以快速学习和上手kotlin
今天来综合使用各种组件，搭建最新MVVM项目框架，利用Paging3实现列表功能，Paging3和Paging2一样，支持数据库缓存
一、依赖
主项目gradle中导入hilt插件
dependencies {
classpath "com.android.tools.build:gradle:7.0.2"
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.5.20"
classpath 'com.google.dagger:hilt-android-gradle-plugin:2.28.1-alpha'
}
module依赖hilt、kapt插件
plugins {
id 'com.android.application'
id 'kotlin-android'
id 'kotlin-kapt'
id 'dagger.hilt.android.plugin'
}
DataBinding、ViewBinding支持：
buildFeatures {
dataBinding = true
viewBinding = true
}
在kotlin1.5.20下使用Hilt编译会出现问题：
Expected @HiltAndroidApp to have a value. Did you forget to apply the Gradle Plugin?
解决方法：
kapt {
javacOptions {
option("-Adagger.hilt.android.internal.disableAndroidSuperclassValidation=true")
}
}
依赖各大组件：
implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.5.1'
implementation 'com.squareup.retrofit2:retrofit:2.9.0'
implementation "com.squareup.retrofit2:converter-gson:2.9.0"
implementation 'com.squareup.okhttp3:logging-interceptor:3.4.1'
implementation "io.coil-kt:coil:1.1.0"
def room_version = "2.3.0"
implementation "androidx.room:room-runtime:$room_version"
implementation "androidx.room:room-ktx:$room_version"
kapt "androidx.room:room-compiler:$room_version"
implementation 'androidx.swiperefreshlayout:swiperefreshlayout:1.1.0-rc01'
implementation "androidx.startup:startup-runtime:1.0.0"
def hilt_version = "2.28-alpha"
implementation "com.google.dagger:hilt-android:$hilt_version"
kapt "com.google.dagger:hilt-android-compiler:$hilt_version"
def hilt_view_version = "1.0.0-alpha01"
implementation "androidx.hilt:hilt-lifecycle-viewmodel:$hilt_view_version"
kapt "androidx.hilt:hilt-compiler:$hilt_view_version"
implementation "androidx.activity:activity-ktx:1.1.0"
implementation "androidx.fragment:fragment-ktx:1.2.5"
implementation "androidx.lifecycle:lifecycle-livedata-ktx:2.2.0"
implementation 'androidx.paging:paging-runtime-ktx:3.0.0-beta03'
二、Hilt注入
Hilt注解释义:
- @HiltAndroidApp：触发Hilt的代码生成
- @AndroidEntryPoint：创建一个依赖容器，该容器遵循Android类的生命周期
- @Module：告诉Hilt如何提供不同类型的实例
- @InstallIn：用来告诉Hilt这个模块会被安装到哪个组件上
- @Provides：告诉Hilt如何获取具体实例
- @Singleton：单例
- @ViewModelInject：通过构造函数，给ViewModel注入实例
1.Application注入HiltAndroidApp
@HiltAndroidApp
class APP : Application()
别忘了在Manifest中配置
2.Activity中开始查找注入对象
使用AndroidEntryPoint注解来表示，Hilt开始查找注入对象
@AndroidEntryPoint
class MainActivity : AppCompatActivity() {
private val binding by lazy {
ActivityMainBinding.inflate(layoutInflater)
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(binding.root)
}
}
3.Hilt注入网络模块
我们准备使用Retrofit封装一个网络模块，需要对该模块使用Module注解和InstallIn注解绑定到对应Android类的生命周期，显然整个APP运行过程中，我们都要使用网络模块，所以选择绑定Application
@InstallIn(ApplicationComponent::class)
@Module
object RetrofitModule {
}
提供一个方法给Hilt获取Okhttp对象，此方法为单例，所以使用Provides和Singleton
{
private val TAG: String = RetrofitModule.javaClass.simpleName
@Singleton
@Provides
fun getOkHttpClient(): OkHttpClient {
val interceptor = HttpLoggingInterceptor {
Log.d(TAG, it)
}.apply { level = HttpLoggingInterceptor.Level.BODY }
return OkHttpClient.Builder().addInterceptor(interceptor).build()
}
}
再提供一个获取Retrofit的方法：
{
@Singleton
@Provides
fun getRetrofit(okHttpClient: OkHttpClient): Retrofit {
return Retrofit.Builder()
.baseUrl(BASE_URL)
.client(okHttpClient)
.addConverterFactory(GsonConverterFactory.create())
.build()
}
}
完整的网络模块代码：
const val BASE_URL = "http://192.168.17.114:8080/pagingserver_war/"
@InstallIn(ApplicationComponent::class)
@Module
object RetrofitModule {
private val TAG: String = RetrofitModule.javaClass.simpleName
@Singleton
@Provides
fun getOkHttpClient(): OkHttpClient {
val interceptor = HttpLoggingInterceptor {
Log.d(TAG, it)
}.apply { level = HttpLoggingInterceptor.Level.BODY }
return OkHttpClient.Builder().addInterceptor(interceptor).build()
}
@Singleton
@Provides
fun getRetrofit(okHttpClient: OkHttpClient): Retrofit {
return Retrofit.Builder()
.baseUrl(BASE_URL)
.client(okHttpClient)
.addConverterFactory(GsonConverterFactory.create())
.build()
}
}
三、接口与实体类
1.根据接口和接口返回的json数据，分别创建API和实体类
api地址：ikds.do?since=0&pagesize=5
服务器数据：
[
{
"id":1,
"title":"扎克·施奈德版正义联盟",
"cover":"https://img9.doubanio.com/view/photo/s_ratio_poster/public/p2634360594.webp",
"rate":"8.9"
},
{
"id":2,
"title":"侍神令",
"cover":"https://img2.doubanio.com/view/photo/s_ratio_poster/public/p2629260713.webp",
"rate":"5.8"
},
{
"id":3,
"title":"双层肉排",
"cover":"https://img1.doubanio.com/view/photo/s_ratio_poster/public/p2633977758.webp",
"rate":"6.7"
},
{
"id":4,
"title":"大地",
"cover":"https://img9.doubanio.com/view/photo/s_ratio_poster/public/p2628845704.webp",
"rate":"6.6"
},
{
"id":5,
"title":"租来的朋友",
"cover":"https://img2.doubanio.com/view/photo/s_ratio_poster/public/p2616903233.webp",
"rate":"6.1"
}
]
实体类：
data class MovieItemModel(
val id: Int,
val title: String,
val cover: String,
val rate: String
)
API接口：
interface MovieService {
@GET("ikds.do")
suspend fun getMovieList(
@Query("since") since: Int,
@Query("pagesize") pagesize: Int
): List
}
2.在网络模块RetrofitModule中新增获取MovieService的方法
{
@Singleton
@Provides
fun provideMovieService(retrofit: Retrofit): MovieService {
return retrofit.create(MovieService::class.java)
}
}
四、Hilt注入数据库模块
1.Room相关基类
使用Room数据库，首先创建Entity，这边加了一个页码的字段：
@Entity
data class MovieEntity(
@PrimaryKey
val id: Int,
val title: String,
val cover: String,
val rate: String,
val page: Int//页码
)
创建Dao，Room支持返回PagingSource对象，可以直接和我们的Paging结合使用了：
@Dao
interface MovieDao {
@Insert(onConflict = OnConflictStrategy.REPLACE)
suspend fun insert(movieList: List)
@Query("SELECT * FROM MovieEntity")
fun getMovieList(): PagingSource
@Query("DELETE FROM MovieEntity")
suspend fun clear()
}
定义Database抽象类：
@Database(entities = [MovieEntity::class], version = 1, exportSchema = false)
abstract class AppDatabase : RoomDatabase() {
abstract fun movieDao(): MovieDao
}
2.Hilt注入数据库模块
数据库模块同样需要伴随应用的生命周期，所以还是和Application绑定
提供方法给Hilt获取AppDatabase、MovieDao
@InstallIn(ApplicationComponent::class)
@Module
object RoomModule {
@Singleton
@Provides
fun getAppDatabase(application: Application): AppDatabase {
return Room.databaseBuilder(application, AppDatabase::class.java, "my.db")
.build()
}
@Singleton
@Provides
fun provideMovieDao(appDatabase: AppDatabase): MovieDao {
return appDatabase.movieDao()
}
}
五、Pager配置
我们有了网络模块，数据库模块，接下来就要实现配置Pager，PagingSource我们已经实现了从数据库获取，现在需要的实现的是：网络数据使用RemoteMediator获取
1.网络数据获取：RemoteMediator
结合最初的架构图，RemoteMediator是用于获取网络数据，并将数据存入数据库，我们就可以从数据库获取PagingSource，传递给后续的Pager
@OptIn(ExperimentalPagingApi::class)
class MovieRemoteMediator(
private val api: MovieService,
private val appDatabase: AppDatabase
) : RemoteMediator() {
override suspend fun load(
loadType: LoadType,
state: PagingState
): MediatorResult {
TODO("Not yet implemented")
}
}
load函数先放一边，先来实现架构中其他模块
2.对ViewModel暴露获取数据接口：Repository
定义一个Repository接口获取Flow
interface Repository {
fun fetchList(): Flow>
}
实现类，使用MovieItemModel作为泛型类型，并返回Pager的Flow：
class MovieRepositoryImpl(
private val api: MovieService,
private val appDatabase: AppDatabase
) : Repository {
override fun fetchList(): Flow> {
val pageSize = 10
return Pager(
config = PagingConfig(
initialLoadSize = pageSize * 2,
pageSize = pageSize,
prefetchDistance = 1
),
remoteMediator = MovieRemoteMediator(api, appDatabase)
) {
appDatabase.movieDao().getMovieList()
}.flow.flowOn(Dispatchers.IO).map {
}
}
}
编译器上可以看到map中的it对象为Paging
3.Data Mapper
Data Mapper广泛应用于MyBatis，Data Mapper将数据源的Model（MovieEntity）转换为页面显示Model（MovieItemModel），两者分开的原因就是为了Model层和View层进一步解耦
定义统一转换接口：
interface Mapper {
fun map(input: I): O
}
针对MovieEntity和MovieItemModel实现接口
class MovieEntity2ItemModelMapper : Mapper {
override fun map(input: MovieEntity): MovieItemModel {
return input.run {
MovieItemModel(
id = id,
title = title,
cover = cover,
rate = rate
)
}
}
}
4.利用Mapper对Repository转换
有了Mapper后，就可以将2.中我们的MovieEntity转换为MovieItemModel了
class MovieRepositoryImpl(
private val api: MovieService,
private val appDatabase: AppDatabase,
private val mapper: MovieEntity2ItemModelMapper
) : Repository {
@OptIn(ExperimentalPagingApi::class)
override fun fetchList(): Flow> {
val pageSize = 10
return Pager(
config = PagingConfig(
initialLoadSize = pageSize * 2,
pageSize = pageSize,
prefetchDistance = 1
),
remoteMediator = MovieRemoteMediator(api, appDatabase)
) {
appDatabase.movieDao().getMovieList()
}.flow.flowOn(Dispatchers.IO).map { pagingData ->
pagingData.map { mapper.map(it) }
}
}
}
5.Hilt注入Repository
Repository的生命周期并不是伴随应用的，而是伴随Activity，所以安装到ActivityComponent
同样方法也不是单例的，而是根据Activity，使用ActivityScoped注解
@InstallIn(ActivityComponent::class)
@Module
object RepositoryModule {
@ActivityScoped
@Provides
fun provideMovieRepository(
api: MovieService,
appDatabase: AppDatabase
): MovieRepositoryImpl {
return MovieRepositoryImpl(api, appDatabase, MovieEntity2ItemModelMapper())
}
}
六、ViewModel
Model层的架构搭建完毕后，我们需要ViewModel层与Model层作数据交互
Hilt注入ViewModel构造函数
ViewModel中需要Repository对象作为属性，而Hilt支持使用ViewModelInject注解给ViewModel构造函数注入
class MovieViewModel @ViewModelInject constructor(
private val repository: MovieRepositoryImpl
) : ViewModel() {
val data = repository.fetchList().cachedIn(viewModelScope).asLiveData()
}
七、Adapter与Coil
ViewModel完成后，接下来需要RecyclerView的Adapter，这块和之前的Paggin3一样
1.布局文件
2.BindingAdapter
使用BindingAdapter自定义一个image属性
这边选用Coil作为图片加载框架，Coil相较于其他框架拥有更好的性能、更小的体积、易用性、结合了协程、androidx等最新技术、还拥有缓存、动态采样、加载暂停/终止等功能
@BindingAdapter("image")
fun setImage(imageView: ImageView, imageUrl: String) {
imageView.load(imageUrl) {
placeholder(R.drawable.ic_launcher_foreground)//占位图
crossfade(true)//淡入淡出
}
}
3.Adapter实现
使用ViewDataBinding作为属性，定义一个基类ViewHolder
class BindingViewHolder(val binding: ViewDataBinding) : RecyclerView.ViewHolder(binding.root)
Adapter继承PagingDataAdapter，并传入一个DiffUtil.ItemCallback
class MoviePagingAdapter : PagingDataAdapter(
object : DiffUtil.ItemCallback() {
override fun areItemsTheSame(oldItem: MovieItemModel, newItem: MovieItemModel): Boolean {
return oldItem.id == newItem.id
}
override fun areContentsTheSame(oldItem: MovieItemModel, newItem: MovieItemModel): Boolean {
return oldItem == newItem
}
}
) {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): BindingViewHolder {
val binding = ItemBinding.inflate(LayoutInflater.from(parent.context), parent, false)
return BindingViewHolder(binding)
}
override fun onBindViewHolder(holder: BindingViewHolder, position: Int) {
if (getItem(position) != null)
(holder.binding as ItemBinding).movie = getItem(position)
}
}
4.为RecyclerView添加扩展函数
为了后续Paging的使用，为RecyclerView添加设置Adapter和liveData的扩展函数：
fun RecyclerView.setPagingAdapter(
owner: LifecycleOwner,
adapter: PagingDataAdapter,
liveData: LiveData>
) {
liveData.observe(owner) {
adapter.submitData(owner.lifecycle, it)
}
}
Activity的代码如下：
@AndroidEntryPoint
class MainActivity : AppCompatActivity() {
private val binding by lazy {
ActivityMainBinding.inflate(layoutInflater)
}
private val viewModel: MovieViewModel by viewModels()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(binding.root)
binding.recyclerview.setPagingAdapter(
owner = this,
adapter = MoviePagingAdapter(),
liveData = viewModel.data
)
}
}
八、实现RemoteMediator
之前未实现load函数的代码：
@OptIn(ExperimentalPagingApi::class)
class MovieRemoteMediator(
private val api: MovieService,
private val appDatabase: AppDatabase
) : RemoteMediator() {
override suspend fun load(
loadType: LoadType,
state: PagingState
): MediatorResult {
TODO("Not yet implemented")
}
}
1.MediatorResult
load函数需要一个MediatorResult类型的返回值，MediatorResult有三种返回参数：
- MediatorResult.Error(e)：出现错误
- MediatorResult.Success(endOfPaginationReached = false)：请求成功且有数据(还有下一页)
- MediatorResult.Success(endOfPaginationReached = true)：请求成功但没有数据(到底了)
返回MediatorResult.Success，pager就会从数据库中拿数据，load函数初步实现：
{
try {
//1.判断loadType
//2.请求网络分页数据
//3.存入数据库
val endOfPaginationReached = true
return MediatorResult.Success(endOfPaginationReached = endOfPaginationReached)
} catch (e: Exception) {
return MediatorResult.Error(e)
}
}
2.LoadType
LoadType为枚举类，有三个对象：
- Refresh：首次加载数据和调用PagingDataAdapter.refresh()时触发
- Append：加载更多数据时触发
- Prepend：在列表头部添加数据时触发，Refresh触发时也会触发
第一步就需要判断LoadType的状态，如果是Refresh，那么数据库中没有数据，就要从网络获取数据，Refresh状态下load函数执行完毕后会自动再次调用load函数，此时的LoadType为Append，此时数据库中有数据了，直接返回Success通知Pager可以从数据库取数据了
{
try {
//1.判断loadType
val pageKey = when (loadType) {
//首次加载
LoadType.REFRESH -> null
//REFRESH之后还会调用load（REFRESH时数据库中没有数据），来加载开头的数据，直接返回成功就可以了
LoadType.PREPEND -> return MediatorResult.Success(endOfPaginationReached = false)
//加载更多
LoadType.APPEND -> {
}
}
//2.请求网络分页数据
val page = pageKey ?: 0
//3.存入数据库
val endOfPaginationReached = true
return MediatorResult.Success(endOfPaginationReached = endOfPaginationReached)
} catch (e: Exception) {
return MediatorResult.Error(e)
}
}
3.PagingState
对于下一页的数据，则要使用PagingState获取了，PagingState分为两部分组成：
- pages：上一页的数据，主要用来获取最后一个item，作为下一页的开始位置
- config：配置Pager时的PagingConfig，可以获取到pageSize等一系列初始化配置的值
如果上一页最后一个item为空，那么表示列表加载到底了，否则获取到需要加载的当前page
{
//加载更多
LoadType.APPEND -> {
val lastItem = state.lastItemOrNull() ?: return MediatorResult.Success(
endOfPaginationReached = true
)
lastItem.page//返回当前页
}
}
4.网络获取数据和存入数据库
接下来就是从网络获取数据了：
override suspend fun load(
loadType: LoadType,
state: PagingState
): MediatorResult {
try {
//1.判断loadType
val pageKey = when (loadType) {
//首次加载
LoadType.REFRESH -> null
//REFRESH之后还会调用load（REFRESH时数据库中没有数据），来加载开头的数据，直接返回成功就可以了
LoadType.PREPEND -> return MediatorResult.Success(endOfPaginationReached = false)
//加载更多
LoadType.APPEND -> {
val lastItem = state.lastItemOrNull() ?: return MediatorResult.Success(
endOfPaginationReached = true
)
lastItem.page//返回当前页
}
}
//2.请求网络分页数据
val page = pageKey ?: 0
val result = api.getMovieList(
page * state.config.pageSize,
state.config.pageSize
)
//3.存入数据库
val endOfPaginationReached = true
return MediatorResult.Success(endOfPaginationReached = endOfPaginationReached)
} catch (e: Exception) {
return MediatorResult.Error(e)
}
}
将服务器对象转换为本地数据库对象后，存入数据库，完整RemoteMediator代码：
@OptIn(ExperimentalPagingApi::class)
class MovieRemoteMediator(
private val api: MovieService,
private val appDatabase: AppDatabase
) : RemoteMediator() {
override suspend fun load(
loadType: LoadType,
state: PagingState
): MediatorResult {
try {
//1.判断loadType
val pageKey = when (loadType) {
//首次加载
LoadType.REFRESH -> null
//REFRESH之后还会调用load（REFRESH时数据库中没有数据），来加载开头的数据，直接返回成功就可以了
LoadType.PREPEND -> return MediatorResult.Success(endOfPaginationReached = false)
//加载更多
LoadType.APPEND -> {
val lastItem = state.lastItemOrNull() ?: return MediatorResult.Success(
endOfPaginationReached = true
)
lastItem.page//返回当前页
}
}
//2.请求网络分页数据
val page = pageKey ?: 0
val result = api.getMovieList(
page * state.config.pageSize,
state.config.pageSize
)
//服务器对象转换为本地数据库对象
val entity = result.map {
MovieEntity(
id = it.id,
title = it.title,
cover = it.cover,
rate = it.rate,
page = page + 1
)
}
//3.存入数据库
val movieDao = appDatabase.movieDao()
appDatabase.withTransaction {
if (loadType == LoadType.REFRESH) {
movieDao.clear()
}
movieDao.insert(entity)
}
val endOfPaginationReached = result.isEmpty()
return MediatorResult.Success(endOfPaginationReached = endOfPaginationReached)
} catch (e: Exception) {
return MediatorResult.Error(e)
}
}
}
运行后的效果：
联动.gif
九、刷新
1.上拉刷新、重试按钮、错误信息
上拉刷新、重试按钮、错误信息布局文件如下：
之前我们使用Paging的LoadStateAdapter，直接设置到PagingDataAdapter上就可以了，刷新对应的ViewHolder如下：
class NetWorkStateItemViewHolder(
private val binding: NetworkStateItemBinding,
val retryCallback: () -> Unit
) : RecyclerView.ViewHolder(binding.root) {
fun bindData(data: LoadState){
binding.apply {
// 正在加载，显示进度条
progress.isVisible = data is LoadState.Loading
// 加载失败，显示并点击重试按钮
retryButton.isVisible = data is LoadState.Error
retryButton.setOnClickListener { retryCallback() }
// 加载失败显示错误原因
errorMsg.isVisible = !(data as? LoadState.Error)?.error?.message.isNullOrBlank()
errorMsg.text = (data as? LoadState.Error)?.error?.message
}
}
}
inline var View.isVisible: Boolean
get() = visibility == View.VISIBLE
set(value) {
visibility = if (value) View.VISIBLE else View.GONE
}
Adapter代码：
class FooterAdapter(
val adapter: MoviePagingAdapter
) : LoadStateAdapter() {
override fun onBindViewHolder(holder: NetWorkStateItemViewHolder, loadState: LoadState) {
//水平居中
val params = holder.itemView.layoutParams
if (params is StaggeredGridLayoutManager.LayoutParams) {
params.isFullSpan = true
}
holder.bindData(loadState)
}
override fun onCreateViewHolder(
parent: ViewGroup,
loadState: LoadState
): NetWorkStateItemViewHolder {
val binding =
NetworkStateItemBinding.inflate(LayoutInflater.from(parent.context), parent, false)
return NetWorkStateItemViewHolder(binding) { adapter.retry() }
}
}
Activity中配置下PagingDataAdapter，并为RecyclerView设置ConcatAdapter，一定要设置成withLoadStateFooter函数返回的Adapter，否则不会有效果！！
val adapter = MoviePagingAdapter()
binding.recyclerview.adapter = adapter
.run { withLoadStateFooter(FooterAdapter(this)) }
2.下拉刷新
下拉刷新和之前也是相同的，布局中嵌套一个SwipeRefreshLayout：
Activity中对PagingDataAdapter的loadState进行监听：
lifecycleScope.launchWhenCreated {
//监听adapter状态
adapter.loadStateFlow.collect {
//根据刷新状态来通知swiprefreshLayout是否刷新完毕
binding.refreshLayout.isRefreshing = it.refresh is LoadState.Loading
}
}
十、App Starup实现无网络数据组件初始化
RemoteMediator中可以在无网络时从数据库获取数据，所以load函数中我们还需要对网络状态进行判断，无网络时，直接返回Success
1.获取网络状态的扩展函数
定义一个扩展函数用来获取网络状态：
@Suppress("DEPRECATION")
@SuppressLint("MissingPermission")
fun Context.isConnectedNetwork(): Boolean = run {
val cm = getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
val activeNetwork: NetworkInfo? = cm.activeNetworkInfo
activeNetwork?.isConnectedOrConnecting == true
}
Manifest中不要忘了加权限
2.新建帮助类，初始化Context
object AppHelper {
lateinit var mContext: Context
fun init(context: Context) {
this.mContext = context
}
}
3.RemoteMediator中判断网络状态并返回
//无网络从本地数据库获取数据
if (!AppHelper.mContext.isConnectedNetwork()) {
return MediatorResult.Success(endOfPaginationReached = false)
}
此时AppHelper的init函数还没有调用
4.App Starup
image.png
App Starup是JetPack的新成员，提供了在App启动时初始化组件简单、高效的方法，还可以指定初始化顺序，我们新建一个类继承于Initializer：
class AppInitializer : Initializer {
override fun create(context: Context) {
AppHelper.init(context)
}
//按顺序执行初始化
override fun dependencies(): MutableList>> = mutableListOf()
}
最后还需要在Manifest中注册：
最终效果：