Android 获取视图和视图模型以使用公共协议进行通信

我试图告诉视图，它需要使用LiveData导航到两个目的地之一：

class IntroFragment : Fragment()
{
    private lateinit var introViewModel : IntroViewModel

    override fun onCreateView( inflater : LayoutInflater,
                               container : ViewGroup?,
                               savedInstanceState : Bundle?): View? 
    {
        introViewModel = ViewModelProviders.of( this ).get( IntroViewModel::class.java )
        return inflater.inflate( R.layout.fragment_Intro, container, false )
    }

    override

    fun onViewCreated( view: View, savedInstanceState: Bundle? )
    {
        introViewModel.navigateToSection1.observe(this, Observer {
            Navigation.findNavController( view ).navigate( R.id.action_showSection1 )
        });

        introViewModel.navigateToSection2.observe(this, Observer {
            Navigation.findNavController( view ).navigate( R.id.action_showSection2 )
        });
    }
}

简介模型：

class IntroViewModel : ViewModel()
{
    private val _navigateToSection1 = MutableLiveData<Boolean>()
    val navigateToNotificationSettings: LiveData<Boolean>
        get() = _navigateToSection1

    private val _navigateToSection2 = MutableLiveData<Boolean>()
    val navigateToSection2: LiveData<Boolean>
        get() = _navigateToSection2

    init
    {
        _navigateToSection1 = true
    }
}

class IntroViewModel : ViewModel()
{
    private val _navigateTo = MutableLiveData<IntroProtocol>()
    val navigateTo: LiveData<IntroProtocol>
        get() = _navigateTo

    init
    {
        _navigateTo = IntroProtocol.navigateToSection1() // I get "Unresolved reference navigateToSection1"
    }
}

然后将interfaces方法作为参数传递回视图，如下所示：

class IntroFragment : Fragment(), IntroProtocol
{
    private lateinit var introViewModel : IntroViewModel

    override fun onCreateView( inflater           : LayoutInflater,
                               container          : ViewGroup?,
                               savedInstanceState : Bundle?         ): View?
    {
        introViewModel = ViewModelProviders.of( this ).get( IntroViewModel::class.java )
        return inflater.inflate( R.layout.fragment_Intro, container, false )
    }


    override fun onViewCreated( view: View, savedInstanceState: Bundle? )
    {
        introViewModel.navigateTo.observe( this, Observer {
            callLocalMethodByName( this ) // not sure how call the local method by name dynamically
        });
    }


    override fun navigateToSection1()
    {
        Navigation.findNavController( view ).navigate( R.id.action_showSection1 )
    }


    override fun navigateToSection2()
    {
        Navigation.findNavController( view ).navigate( R.id.action_showSection2 )
    }
}

_navigateToSection1.value = true

简介模型：

class IntroViewModel : ViewModel()
{
    private val _navigateToSection1 = MutableLiveData<Boolean>()
    val navigateToNotificationSettings: LiveData<Boolean>
        get() = _navigateToSection1

    private val _navigateToSection2 = MutableLiveData<Boolean>()
    val navigateToSection2: LiveData<Boolean>
        get() = _navigateToSection2

    init
    {
        _navigateToSection1 = true
    }
}

class IntroViewModel : ViewModel()
{
    private val _navigateTo = MutableLiveData<IntroProtocol>()
    val navigateTo: LiveData<IntroProtocol>
        get() = _navigateTo

    init
    {
        _navigateTo = IntroProtocol.navigateToSection1() // I get "Unresolved reference navigateToSection1"
    }
}

---

但我不知道该怎么做，如果可能的话。我希望传递interfaces方法的原因是，如果有一个干净的定义/协议，ViewModel知道它可以调用哪些方法，并且视图将继承这些方法，这将非常方便，从而产生良好的结构。这可能吗？如果不需要，还有什么替代方案？

我想说您不需要该接口，但要为您的可变LiveData提供一个值，您需要这样做：

class IntroFragment : Fragment(), IntroProtocol
{
    private lateinit var introViewModel : IntroViewModel

    override fun onCreateView( inflater           : LayoutInflater,
                               container          : ViewGroup?,
                               savedInstanceState : Bundle?         ): View?
    {
        introViewModel = ViewModelProviders.of( this ).get( IntroViewModel::class.java )
        return inflater.inflate( R.layout.fragment_Intro, container, false )
    }


    override fun onViewCreated( view: View, savedInstanceState: Bundle? )
    {
        introViewModel.navigateTo.observe( this, Observer {
            callLocalMethodByName( this ) // not sure how call the local method by name dynamically
        });
    }


    override fun navigateToSection1()
    {
        Navigation.findNavController( view ).navigate( R.id.action_showSection1 )
    }


    override fun navigateToSection2()
    {
        Navigation.findNavController( view ).navigate( R.id.action_showSection2 )
    }
}

_navigateToSection1.value = true