Hilt：自动获取 Fragment LifecycleOwner 和上下文答案

【问题标题】：Hilt: Get Fragment LifecycleOwner and context automagicallyHilt：自动获取 Fragment LifecycleOwner 和上下文
【发布时间】：2021-08-04 11:34:08
【问题描述】：

当我在片段中注入我的依赖项时，我想自动获取片段上下文和生命周期所有者（例如这里的 viewLifecycleOwner）。我的问题是，怎么做，因为没有对应的@FragmentContext，就像有一个@ActivityContext。此外，我想为这个依赖动态分配一个变量。

我的依赖

class LoginDialog(
    context: Context, // get this from fragment
    private val mLifecycleOwner: LifecycleOwner, // get this from fragment
    private val loginTitle: LoginTitle, // define this when injecting
) : AlertDialog(context, R.style.LoginDialogTheme) {
    private var _binding: LoginLoadingScreenBinding? = null
    private val binding: LoginLoadingScreenBinding get() = _binding!!

    override fun onCreate(savedInstanceState: Bundle?) {
        initDialog()
        super.onCreate(savedInstanceState)
    }

    override fun show() {
        if (isShowing) return
        _binding = LoginLoadingScreenBinding.inflate(layoutInflater).apply { lifecycleOwner = mLifecycleOwner }
        super.show()
    }

    override fun dismiss() {
        _binding = null
        super.dismiss()
    }

    /**
     * Calls show internally
     */
    fun onChangeIndicator(mText: String) {
        show()
        binding.indicator = mText
    }

    private fun initDialog() {
        setTitle(loginTitle.title)
        setCancelable(false)
        setView(binding.root)
    }

    sealed class LoginTitle(@StringRes val title: Int) {
        object Login : LoginTitle(R.string.loading_login_title)
        object Registration : LoginTitle(R.string.loading_registration_title)
        object ChangingEmail : LoginTitle(R.string.user_data_changing_email)
    }

}

注入

@AndroidEntryPoint
class FragmentA : Fragment() {

    // here, context is requireContext(), 
    // lifecycleOwner is viewLifecylceOwner
    // and loginTitle is LoginDialog.LoginTitle.Login
    @Inject 
    @LoginTitleLogin
    lateinit var loginDialog: LoginDialog
}

【问题讨论】：

标签： android kotlin dagger-2 dagger-hilt

【解决方案1】：

好的，我已经设法通过创建一个 hilt 模块并稍微更改构造函数来解决这个问题，这里是解决方案：

依赖

class LoginDialog(
    private val fragment: Fragment,
    private val loginTitle: LoginTitle,
) : AlertDialog(fragment.requireContext(), R.style.LoginDialogTheme) {
    private var _binding: LoginLoadingScreenBinding? = null
    private val binding: LoginLoadingScreenBinding get() = _binding!!

    override fun onCreate(savedInstanceState: Bundle?) {
        initDialog()
        super.onCreate(savedInstanceState)
    }

    override fun show() {
        if (isShowing) return
        _binding = LoginLoadingScreenBinding.inflate(layoutInflater).apply { lifecycleOwner = fragment.viewLifecycleOwner }
        super.show()
    }

    override fun dismiss() {
        _binding = null
        super.dismiss()
    }

    /**
     * Calls show internally
     */
    fun onChangeIndicator(mText: String) {
        show()
        binding.indicator = mText
    }

    private fun initDialog() {
        setTitle(loginTitle.title)
        setCancelable(false)
        setView(binding.root)
    }

    sealed class LoginTitle(@StringRes val title: Int) {
        object Login : LoginTitle(R.string.loading_login_title)
        object Registration : LoginTitle(R.string.loading_registration_title)
        object ChangingEmail : LoginTitle(R.string.user_data_changing_email)
    }

}

模块

@Module
@InstallIn(FragmentComponent::class)
object FragmentModule {

    @LoginTitle
    @Provides
    fun provideLoginDialogWithLoginTitle(fragment: Fragment) = LoginDialog(
        fragment,
        LoginDialog.LoginTitle.Login
    )

    @RegistrationTitle
    @Provides
    fun provideLoginDialogWithRegistrationTitle(fragment: Fragment) = LoginDialog(
        fragment,
        LoginDialog.LoginTitle.Registration
    )

    @ChangingEmailTitle
    @Provides
    fun provideLoginDialogWithChangingEmailTitle(fragment: Fragment) = LoginDialog(
        fragment,
        LoginDialog.LoginTitle.ChangingEmail
    )

}

@Qualifier
@Retention(AnnotationRetention.RUNTIME)
annotation class LoginTitle

@Qualifier
@Retention(AnnotationRetention.RUNTIME)
annotation class RegistrationTitle

@Qualifier
@Retention(AnnotationRetention.RUNTIME)
annotation class ChangingEmailTitle

用法

@AndroidEntryPoint
class MyFragment : Fragment() {


    @Inject
    @LoginTitle
    lateinit var loginDialog: LoginDialog
}

【讨论】：