Android MVVM+coroutine+retrofit+flow+hilt

概述

代码结构：

依赖注入层

数据库：

@Module
@InstallIn(SingletonComponent::class)
class DBModule {@Singleton@Providesfun provideDB(application: Application): AppDatabase {return AppDatabase.getDatabase(application)}@Singleton@Providesfun provideCacheDao(db: AppDatabase): CacheDao {return db.cacheDao()}
}

网络请求：

@Module
@InstallIn(SingletonComponent::class)
class NetworkModule {@Singleton@Providesfun provideOkHttpClient(): OkHttpClient {return HttpManager.okHttpClient}@Singleton@Providesfun provideRetrofit(okHttpClient: OkHttpClient): Retrofit {return HttpManager.retrofit}@Singleton@Providesfun provideLoginApi(retrofit: Retrofit): LoginApi {return retrofit.create(LoginApi::class.java)}@Singleton@Providesfun provideArticleApi(retrofit: Retrofit): ArticleApi {return retrofit.create(ArticleApi::class.java)}
}

数据层

open class BaseModel {@Injectlateinit var cacheHelper: CacheHelperfun <T> requestForResult(block: suspend () -> BaseResponse<T>): Flow<ResultState<T>> {return flow<ResultState<T>> {val response = block()if (response.isSuccessful()) {emit(ResultState.Success(response.data!!))} else {val serverException = ServerException(response.errorCode, response.errorMsg)val e = ExceptionHandler.handleException(serverException)emit(ResultState.Error(e, e.displayMessage))}}.flowOn(Dispatchers.IO).catch {val e = ExceptionHandler.handleException(it)emit(ResultState.Error(e, e.displayMessage))}}suspend fun <T> requestForResult(cacheName: String,cacheBlock: () -> T?,block: suspend () -> BaseResponse<T>): Flow<ResultState<T>> {return flow {val cacheData = cacheBlock()cacheData?.let {emit(ResultState.Success(cacheData, true))}val response = block()if (response.isSuccessful()) {cacheHelper.saveCache(cacheName, response.data!!)emit(ResultState.Success(response.data, false))} else {val serverException = ServerException(response.errorCode, response.errorMsg)val e = ExceptionHandler.handleException(serverException)emit(ResultState.Error(e, e.displayMessage))}}.flowOn(Dispatchers.IO).catch {val e = ExceptionHandler.handleException(it)emit(ResultState.Error(e, e.displayMessage))}}
}

class ArticleModel @Inject constructor() : BaseModel() {@Injectlateinit var articleApi: ArticleApisuspend fun getArticleList(): Flow<ResultState<ArrayList<ArticleBean>>> {val cacheName = "article_list"return requestForResult(cacheName, {cacheHelper.getCache<ArrayList<ArticleBean>>(cacheName, object : TypeToken<ArrayList<ArticleBean>>() {}.type)}, {articleApi.getArticleList()})}
}

视图层

abstract class BaseActivity<VB : ViewBinding> : AppCompatActivity() {private lateinit var _mViewBinding: VBprotected val mViewBinding get() = _mViewBindingoverride fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)_mViewBinding = createViewBinding()setContentView(_mViewBinding.root)initViews()initData(savedInstanceState)}abstract fun createViewBinding(): VBabstract fun initViews()abstract fun initData(savedInstanceState: Bundle?)
}

@AndroidEntryPoint
class ArticleListActivity : BaseActivity<ActivityArticleListBinding>() {private val mList = arrayListOf<ArticleBean>()private val articleListViewModel by viewModels<ArticleViewModel>()private val progressDialog: ProgressDialog by lazy {ProgressDialog(this).apply {setMessage("加载中")}}override fun createViewBinding(): ActivityArticleListBinding {return ActivityArticleListBinding.inflate(layoutInflater)}override fun initViews() {}override fun initData(savedInstanceState: Bundle?) {mViewBinding.rvArticleList.adapter = ArticleAdapter(this, mList)mViewBinding.btnGetArticleList.setOnClickListener {getArticleList()}observe()}private fun getArticleList() {articleListViewModel.getArticleList()}private fun observe() {lifecycleScope.launch {repeatOnLifecycle(Lifecycle.State.RESUMED) {articleListViewModel.articleFlow.collect {when (it) {is ResultState.Loading -> showLoading()is ResultState.Error -> {showToast(it.message)hideLoading()}is ResultState.Success -> {hideLoading()updateUI(it.data)}}}}}}private fun updateUI(list: ArrayList<ArticleBean>?) {mList.clear()if (list != null) {mList.addAll(list)}mViewBinding.rvArticleList.adapter!!.notifyDataSetChanged()}private fun showLoading() {progressDialog.show()}private fun hideLoading() {progressDialog.hide()}
}

模型视图层

open class BaseViewModel : ViewModel() {fun launchMain(block: suspend CoroutineScope.() -> Unit) {viewModelScope.launch(Dispatchers.Main) {block()}}fun launchIO(block: suspend CoroutineScope.() -> Unit) {viewModelScope.launch(Dispatchers.IO) {block()}}fun launchDefault(block: suspend CoroutineScope.() -> Unit) {viewModelScope.launch(Dispatchers.Default) {block()}}
}

@HiltViewModel
class ArticleViewModel @Inject constructor(private val articleModel: ArticleModel
) : BaseViewModel() {private val _articleFlow =MutableStateFlow<ResultState<ArrayList<ArticleBean>>>(ResultState.None)val articleFlow get() = _articleFlow.asStateFlow()fun getArticleList() {launchIO {articleModel.getArticleList().onStart {_articleFlow.value = ResultState.Loading}.collect {_articleFlow.value = it}}}
}

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