android - 在 Kotlin 中使用 safeArgs 导航抛出和错误

Question

我有一个 fragment ，它可以通过不带参数的底部导航栏导航到，也可以从带参数的不同 fragment 导航到。导航本身工作得很好，但是一旦我添加了我的参数，它就会崩溃。
我不确定需要多少代码，如果不完整，请见谅:
这是我的导航 fragment :

<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/homeFragment">

<fragment
    android:id="@+id/homeFragment"
    android:name="fh.wfp2.flatlife.ui.views.HomeFragment"
    android:label="Flatlife"
    tools:layout="@layout/home_fragment" />
<fragment
    android:id="@+id/todoFragment"
    android:name="fh.wfp2.flatlife.ui.views.TodoFragment"
    android:label="Todos">
    <action
        android:id="@+id/action_todoFragment_to_addTodoFragment"
        app:destination="@id/addTodoFragment" />
    <argument
        android:name="taskname"
        app:argType="string" />
    <argument
        android:name="isImportant"
        app:argType="boolean" />
</fragment>
<fragment
    android:id="@+id/addTodoFragment"
    android:name="fh.wfp2.flatlife.ui.views.AddTodoFragment"
    android:label="AddTodoFragment">
    <action
        android:id="@+id/action_addTodoFragment_to_todoFragment"
        app:destination="@id/todoFragment" />


</fragment>
</navigation>

这是我的 addTodoFragment :

class AddTodoFragment : Fragment(R.layout.add_task_fragment) {

private lateinit var binding: AddTaskFragmentBinding

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    super.onViewCreated(view, savedInstanceState)
 
    binding = AddTaskFragmentBinding.bind(view)
    binding.bAddTodo.setOnClickListener {
        if (binding.etAddTodo.text.isNotEmpty()) {
           // viewModel.onAddTodoClicked(binding.etAddTodo.text.toString(), 
binding.cbImportant.isChecked)
           findNavController().navigate(
                AddTodoFragmentDirections.actionAddTodoFragmentToTodoFragment(
                    binding.etAddTodo.text.toString(), binding.cbImportant.isChecked
                )
            )
        } else {
            Snackbar.make(it, "The task field can't be empty", Snackbar.LENGTH_SHORT).show()
            
        }
    }

}
}

这就是我试图在 中获取参数的方式TodoFragment .

private val args: TodoFragmentArgs by navArgs()
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
//setting binding and other onClickListeners but they work fine

//reading args
//this i thought would work because then args only get read if not null
args?.let { //debugger stops here and app crashes
        if(args.taskname.isNotEmpty())
        viewModel.onAddTodoClick(Todo(name = args.taskname, isImportant = args.isImportant))
    }

/*second try which I took directly from developers.android but which doesn't make sense in my case i 
think because the args could be null I guess

val todoName = args.taskname
    val isImportant = args.isImportant
    viewModel.onAddTodoClick(Todo(name = todoName, isImportant = isImportant))
*/

}

这是我收到的错误消息:

我希望我的意思很清楚，否则，我会更新问题。这可能很简单，但我无法完全理解它。

Answer 1

val args = arguments?.let {
    SecondFragmentArgs.fromBundle(
        it
    )
}
if (args != null) {
    firstDataList = args.taskName
    secondDataList = args.isImportant
}

这就是接收 fragment 代码的样子。这应该有效。