使用导航组件将一个片段的值传递给另一个片段时未生成 FragmentArgs class

Question

这是我的 FragmentTwo 片段 class 代码。

class FragmentTwo : Fragment() {

    override fun onCreateView(
            inflater: LayoutInflater, container: ViewGroup?,
            savedInstanceState: Bundle?,
    ): View? {
        // Inflate the layout for this fragment
        val binding : FragmentTwoBinding = DataBindingUtil.inflate(inflater,R.layout.fragment_two, container, false)
        var args = FragmentTwoArgs.fromBundle(arguments)
        setHasOptionsMenu(true)
        return binding.root
    }

    override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {
        super.onCreateOptionsMenu(menu, inflater)
        inflater?.inflate(R.menu.overflow_menu,menu)
    }

    override fun onOptionsItemSelected(item: MenuItem): Boolean {
        return NavigationUI.onNavDestinationSelected(item!!,findNavController())
                || super.onOptionsItemSelected(item)
    }
}

这是我的 FragmentOne 片段 class 代码：

class FragmentOne : Fragment() {

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        // Inflate the layout for this fragment
        // return inflater.inflate(R.layout.fragment_one, container, false)
        val binding: FragmentOneBinding =
            DataBindingUtil.inflate(inflater, R.layout.fragment_one, container, false)
        binding.clickable = this
        return binding.root
    }

    fun onClicking() {
        //Toast.makeText(activity, "You clicked me.", Toast.LENGTH_SHORT).show()
        //findNavController().navigate(R.id.action_fragmentOne_to_fragmentTwo)

        findNavController().navigate(FragmentOneDirections.actionFragmentOneToFragmentTwo())


    }

}

这是我的导航xml代码。

<?xml version="1.0" encoding="utf-8"?>
<navigation xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/navigation"
    app:startDestination="@id/fragmentOne">

    <fragment
        android:id="@+id/fragmentOne"
        android:name="com.example.fragmentpractise1.FragmentOne"
        android:label="fragment_one"
        tools:layout="@layout/fragment_one" >
        <action
            android:id="@+id/action_fragmentOne_to_fragmentTwo"
            app:destination="@id/fragmentTwo" />
        <argument
            android:name="numViews"
            app:argType="integer"
            android:defaultValue="18" />
    </fragment>
    <fragment
        android:id="@+id/fragmentTwo"
        android:name="com.example.fragmentpractise1.FragmentTwo"
        android:label="fragment_two"
        tools:layout="@layout/fragment_two" />
    <fragment
        android:id="@+id/aboutFragment"
        android:name="com.example.fragmentpractise1.AboutFragment"
        android:label="fragment_about"
        tools:layout="@layout/fragment_about" />
</navigation>

现在我在 FragmentTwo class 代码中遇到错误，因为在将其分配给 args 变量时未生成 FragmentTwoArgs class。我正在使用 Nav safe args 并通过 Nav graph 在 FragmentOne 中定义参数值。任何帮助将不胜感激。

Answer 1

您使用了错误的 Fragment 来声明参数。如果您希望 FragmentTwo 有参数，您应该在导航中使用片段 xml:

<fragment
    android:id="@+id/fragmentTwo"
    android:name="com.example.fragmentpractise1.FragmentTwo"
    android:label="fragment_two"
    tools:layout="@layout/fragment_two">

    <argument
        android:name="numViews"
        app:argType="integer"
        android:defaultValue="18" />
</fragment>

您可能还想使用惰性委托 navArgs():

private val args: FragmentTwoArgs by navArgs()

使用导航组件将一个片段的值传递给另一个片段时未生成 FragmentArgs class

FragmentArgs class in not generated while passing value of one fragment to another by using Navigation components

android

kotlin

android-jetpack-navigation