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
@Provides
fun provideDB(application: Application): AppDatabase {
return AppDatabase.getDatabase(application)
}
@Singleton
@Provides
fun provideCacheDao(db: AppDatabase): CacheDao {
return db.cacheDao()
}
}
网络请求：
@Module
@InstallIn(SingletonComponent::class)
class NetworkModule {
@Singleton
@Provides
fun provideOkHttpClient(): OkHttpClient {
return HttpManager.okHttpClient
}
@Singleton
@Provides
fun provideRetrofit(okHttpClient: OkHttpClient): Retrofit {
return HttpManager.retrofit
}
@Singleton
@Provides
fun provideLoginApi(retrofit: Retrofit): LoginApi {
return retrofit.create(LoginApi::class.java)
}
@Singleton
@Provides
fun provideArticleApi(retrofit: Retrofit): ArticleApi {
return retrofit.create(ArticleApi::class.java)
}
}
数据层
open class BaseModel {
@Inject
lateinit var cacheHelper: CacheHelper
fun <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() {
@Inject
lateinit var articleApi: ArticleApi
suspend 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: VB
protected val mViewBinding get() = _mViewBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
_mViewBinding = createViewBinding()
setContentView(_mViewBinding.root)
initViews()
initData(savedInstanceState)
}
abstract fun createViewBinding(): VB
abstract 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
}
}
}
}
