如果我点击导航控制器中的菜单，如何在两个片段目的地之间传递数据? [英] how to pass data between two fragments destination If I tap a menu in navigation controller?

问题描述

我正在尝试使用导航控制器.我有一个底部导航视图.位于我的 MainActivity 上，它是使用以下代码启动的:

I am trying to use navigation controller. I have a bottom navigation view. that located on my MainActivity, and it is initiated using the code below on :

class MainActivity : AppCompatActivity() {

    lateinit var navController : NavController
    lateinit var logoHeaderImageView : ImageView
    var toolbarMenu : Menu? = null


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        logoHeaderImageView = findViewById(R.id.header_lakuin_image_view)

        navController = Navigation.findNavController(this,R.id.nav_main_host_fragment)



        setupBottomNavMenu(navController)
        setupActionBar(navController)



    }

    fun setupBottomNavMenu(navController: NavController) {
        NavigationUI.setupWithNavController(bottom_navigation_view,navController)
    }

    fun setupActionBar(navController: NavController) {
        setSupportActionBar(main_activity_toolbar)
        main_activity_toolbar.title = ""


        val appBarConfiguration = AppBarConfiguration(
            setOf(
                // set some destination as the top hierarchy destination, to make the up button doesn't show.
                R.id.destination_home,
                R.id.destination_order,
                R.id.destination_favourite,
                R.id.destination_cart,
                R.id.destination_profile

            ))

        NavigationUI.setupWithNavController(main_activity_toolbar,navController,appBarConfiguration)
    }


    override fun onCreateOptionsMenu(menu: Menu?): Boolean {
        menuInflater.inflate(R.menu.menu_main_toolbar, menu)
        toolbarMenu = menu
        return true
    }

    override fun onOptionsItemSelected(item: MenuItem): Boolean {
        return item.onNavDestinationSelected(navController) || super.onOptionsItemSelected(item)
    }




}

这是我的底部导航视图的外观:

here is the look of my bottom navigation view:

所以我想将数据从我的 HomeFragment(目的地主页)传递到 OderFragment(目的地订单).我通常使用 bundle 或 safeArgs 来传递数据，如下面的代码:

So I want to pass data from my HomeFragment (destination home) to OderFragment (destination order). I usually using bundle or safeArgs to pass data like the code below:

var bundle = bundleOf("amount" to amount)
view.findNavController().navigate(R.id.confirmationAction, bundle)

但我不知道该代码放在哪里，如果我想将数据从我的 HomeFragment 传递到 OderFragment

but I don't know where to place that code, If I want to pass data from my HomeFragment to OderFragment

推荐答案

当使用 NavigationUI.setupWithNavController(bottom_navigation_view,navController)(或者，如果你使用 navigation-ui-ktx Kotlin 扩展 bottom_navigation_view.setupWithNavController(navController))，你不能向目的地传递任何自定义参数——全局导航的一个重要部分是它们总是带你到同一个屏幕相同的状态.

When using NavigationUI.setupWithNavController(bottom_navigation_view,navController) (or, if you're using the navigation-ui-ktx Kotlin extension bottom_navigation_view.setupWithNavController(navController)), you can't pass any custom arguments to destinations - an important part of global navigation is that they always take you to the same screen in the same state.

通常，您应该将诸如当前数量之类的数据与导航参数分开保存 - 无论是在持久化数据库、SharedPreferences 中，还是在其他一些可以在进程死亡后幸存的位置中，允许用户继续他们正在做的事情，甚至重启手机等之后

Generally, you should be holding data like the current amount separately from Navigation arguments - whether it is in a persisted database, SharedPreferences, or some other location that would survive process death, allowing users to continue with what they're doing even after restarting their phone, etc.

但是，如果您必须为此使用导航参数，您可以提前为目的地设置默认参数(即，每当您的金额发生变化时):

However, if you must use Navigation arguments for this, you can set the default argument for your destination ahead of time (i.e., whenever your amount changes):

NavDestination orderDestination = navController.graph.findNode(R.id.destination_order)
orderDestination.addArgument("amount", NavArgument.Builder()
    .setType(NavType.FloatType)
    .setDefaultValue(amount)
    .build())

之后，默认情况下，触发 R.id.destination_order 的 BottomNavigationView 将自动包含该参数以及新的 amount 值.

Afterwards, your BottomNavigationView triggering R.id.destination_order will automatically include that argument, along with your new amount value, by default.

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