项目中 Dagger+ViewModel（LiveData） 使用步骤介绍

 

Dagger负责创建工厂，帮忙生产instance

 

1. SetPasswordActivityComponent 桥梁的作用： 将带有 @Inject 的方法或对象和带有 @Module 的类进行关联

2. SetPasswordBindsModule  绑定 4 ViewModel创建工厂到map集合

3. SetPasswordModule 提供 4 ViewModel实例

4. SetPasswordViewModel  感知生命周期的方式存储和管理 UI 相关数据，ViewModel中数据会一直存活即使 activity configuration发生变化，比如横竖屏切换的时候。

5.SetPasswordPresenter 逻辑部分 供 4 SetPasswordViewModel 调用

6.SetPasswordActivity dagger编译后，初始化相关，调用 ViewModel 相关方法

 

DaggerSetPasswordActivityComponent SetPasswordActivity_MembersInjector SetPasswordModule_ProvideViewModelFactory SetPasswordPresenter_Factory SetPasswordViewModel_Factory_Factory

 

注意点：

@Inject注解在构造函数上时，会根据被注解的构造函数生成该类的工厂类@Inject注解在变量和方法上时，表示这些变量和方法需要被注入，会生成相应的注入器 class CPU @Inject constructor() { /* ... */ } class Memory @Inject constructor(private val size: Int) { /* ... */ }

dagger对于有@Inject注解的构造函数的类，会根据被注解的构造函数生成一个实现了Factory接口的工厂类

 

注解在变量和方法上

@Inject lateinit var viewModel: SetPasswordViewModel

编译后可以发现dagger又生成了新的类 SetPasswordActivity_MembersInjector

 

 

 

SetPasswordActivityComponent

@ModuleScope @Component( modules = [ AndroidInjectionModule::class, AccountModule::class, SetPasswordModule::class, SetPasswordBindsModule::class ], dependencies = [CoreComponent::class] ) interface SetPasswordActivityComponent : AndroidInjector<SetPasswordActivity> { @Component.Builder abstract class Builder : AndroidInjector.Builder<SetPasswordActivity>() { /** * 引入和核心组件. * @param coreComponent CoreComponent * @return Builder */ abstract fun coreComponent(coreComponent: CoreComponent): Builder } }

SetPasswordBindsModule 

@Module abstract class SetPasswordBindsModule { /** * 绑定ViewModel创建工厂到map集合. * @param factory SetPasswordViewModel.Factory SetPasswordViewModel_AssistedFactory实例. * @return ViewModelAssistedFactory<out ViewModel> */ @Binds @IntoMap @ViewModelKey(SetPasswordViewModel::class) abstract fun bindFactory(factory: SetPasswordViewModel.Factory): ViewModelAssistedFactory<out ViewModel> }

SetPasswordModule 

@Module class SetPasswordModule { /** * 提供ViewModel实例. * @param viewModelMap MutableMap<Class<out ViewModel>, ViewModelAssistedFactory<out ViewModel>> * @param activity SetPasswordActivity * @return SetPasswordViewModel */ @Provides fun provideViewModel( viewModelMap: MutableMap<Class<out ViewModel>, ViewModelAssistedFactory<out ViewModel>>, activity: SetPasswordActivity ): SetPasswordViewModel = ViewModelProviders.of(activity, ViewModelFactory(viewModelMap, activity, null)).get(SetPasswordViewModel::class.java) }

SetPasswordViewModel 

class SetPasswordViewModel( private val setPasswordPresenter: SetPasswordPresenter, private val accountDataManager: AccountDataManager ) : CoreViewModel() { val accountDataService: AccountDataService? = getAService<AccountDataService>() val canInvite = accountDataService?.userInfo?.value?.canInvite ?: false /** * 设置密码. * @param password String * @return Job */ fun setPassword(password: String, inviteCode: String?) = launch { // 校验密码是否符合格式. _loadingState.value = LoadState.Loading setPasswordPresenter.setPassword(password, inviteCode) .onSuccess { accountDataManager.updatePasswordState() accountDataService?.getToastContent() _loadingState.value = LoadState.Loaded() }.onFailure { if (it is Response.Exception && (it.response.code == ServerCodes.BEHAVIOR_VERIFICATION_CODE || it.response.code == ServerCodes.BEHAVIOR_VERIFICATION_CODE_TWO) ) { _loadingState.value = LoadState.LoadError( Response.Exception( Response( ServerCodes.BEHAVIOR_VERIFICATION_CODE_TWO, "", " " ) ) ) refreshVerifyCode(password, inviteCode) } else { _loadingState.value = LoadState.LoadError(it) } } } /** * 刷新行为验证码 */ private fun refreshVerifyCode(password: String, inviteCode: String?) { getAService<GrowthDataService>()?.checkVerifyCaptcha( GrowthDataService.VERIFYCODE_INVITE, { setPassword(password, inviteCode) }, { if (it is Response.Exception && (it.response.code == ServerCodes.VerificationCode.BEHAVIOR_VERIFICATION_CODE_ERROR)) { refreshVerifyCode(password, inviteCode) } else { _loadingState.value = LoadState.LoadError(it) } }) } class Factory @Inject constructor( private val setPasswordPresenter: SetPasswordPresenter, private val accountDataManager: AccountDataManager ) : ViewModelAssistedFactory<SetPasswordViewModel> { override fun create(handle: SavedStateHandle): SetPasswordViewModel = SetPasswordViewModel(setPasswordPresenter, accountDataManager) } }

SetPasswordPresenter 

class SetPasswordPresenter @Inject constructor( private val accountService: AccountService ) { /** * 新用户设置密码. * @param password String * @return Result<Any> */ suspend fun setPassword(password: String, inviteCode: String?) = safeApiCall { // 先校验密码 password.verifyNumberAndLetter().no { throw KException("密码必须包含数字和字母") } accountService.setNewPassword(SetPasswordRequest(password, inviteCode ?: "")) } }