如何在Android上使用NavigationComponent打開新片段-有解無憂

在我的應用程式中，我使用了單個活動并使用了一些片段！
我想首先顯示SplashFragment并檢查用戶令牌，如果存在則打開HomeFragment否則打開RegisterFragment！

我寫了下面的代碼，但是注冊用戶后顯示下面的錯誤！

日志錯誤：

    java.lang.IllegalArgumentException: Navigation action/destination my.app:id/actionSplashToHome cannot be found from the current destination Destination(my.app:id/registerFragment) label=fragment_register class=my.app.ui.register.RegisterFragment
        at androidx.navigation.NavController.navigate(NavController.kt:1536)
        at androidx.navigation.NavController.navigate(NavController.kt:1468)
        at androidx.navigation.NavController.navigate(NavController.kt:1450)
        at androidx.navigation.NavController.navigate(NavController.kt:1433)
        at my.app.ui.splash.SplashFragment$onViewCreated$1$1.emit(SplashFragment.kt:43)
        at my.app.ui.splash.SplashFragment$onViewCreated$1$1.emit(SplashFragment.kt:38)
        at my.app.utils.UserInfo$getUserToken$$inlined$map$1$2.emit(Emitters.kt:224)
        at kotlinx.coroutines.flow.internal.SafeCollectorKt$emitFun$1.invoke(SafeCollector.kt:15)
        at kotlinx.coroutines.flow.internal.SafeCollectorKt$emitFun$1.invoke(SafeCollector.kt:15)
        at kotlinx.coroutines.flow.internal.SafeCollector.emit(SafeCollector.kt:77)
        at kotlinx.coroutines.flow.internal.SafeCollector.emit(SafeCollector.kt:59)
        at androidx.datastore.core.SingleProcessDataStore$data$1$invokeSuspend$$inlined$map$1$2.emit(Collect.kt:137)
        at kotlinx.coroutines.flow.FlowKt__LimitKt$dropWhile$1$1.emit(Limit.kt:37)
        at kotlinx.coroutines.flow.StateFlowImpl.collect(StateFlow.kt:398)
        at kotlinx.coroutines.flow.StateFlowImpl$collect$1.invokeSuspend(Unknown Source:15)
        at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)

注冊片段代碼：

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        //InitViews
        binding.apply {
            //Submit
            submitBtn.setOnClickListener { it ->
                val name = nameEdt.text.toString()
                val email = emailEdt.text.toString()
                val password = passwordEdt.text.toString()
                //Validation
                if (name.isNotEmpty() || email.isNotEmpty() || password.isNotEmpty()) {
                    body.name = name
                    body.email = email
                    body.password = password

                    viewModel.registerUser(body)

                    viewModel.registerUser.observe(viewLifecycleOwner) { itResponse ->
                        Log.e("UserInfoLog","1 : " itResponse.email.toString())
                        lifecycle.coroutineScope.launchWhenCreated {
                            userDataStore.saveUserToken(itResponse.email.toString())
                            Log.e("UserInfoLog","2 : " itResponse.email.toString())
                            findNavController().navigateUp()
                        }
                    }

                } else {
                    Snackbar.make(it, getString(R.string.fillAllFields), Snackbar.LENGTH_SHORT).show()
                }

SplashFragment 代碼：

        override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        //Check user token
        lifecycle.coroutineScope.launchWhenCreated {
            delay(2000)

            userDataStore.getUserToken().collect {
                if (it.isEmpty()) {
                    findNavController().navigate(R.id.actionSplashToRegister)
                } else {
                    findNavController().navigate(R.id.actionSplashToHome)
                }
            }
        }
    }

導航代碼：

<?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/nav_main"
    app:startDestination="@id/splashFragment">

    <fragment
        android:id="@ id/splashFragment"
        android:name="my.app.ui.splash.SplashFragment"
        android:label="fragment_splash"
        tools:layout="@layout/fragment_splash">
        <action
            android:id="@ id/actionSplashToRegister"
            app:destination="@id/registerFragment"
            app:enterAnim="@anim/nav_default_enter_anim"
            app:exitAnim="@anim/nav_default_exit_anim"
            app:popEnterAnim="@anim/nav_default_pop_enter_anim"
            app:popExitAnim="@anim/nav_default_pop_exit_anim" />
        <action
            android:id="@ id/actionSplashToHome"
            app:destination="@id/homeFragment"
            app:enterAnim="@anim/nav_default_enter_anim"
            app:exitAnim="@anim/nav_default_exit_anim"
            app:popEnterAnim="@anim/nav_default_pop_enter_anim"
            app:popExitAnim="@anim/nav_default_pop_exit_anim"/>
    </fragment>
    <fragment
        android:id="@ id/registerFragment"
        android:name="my.app.ui.register.RegisterFragment"
        android:label="fragment_register"
        tools:layout="@layout/fragment_register">
        <action
            android:id="@ id/actionRegisterToHome"
            app:destination="@id/homeFragment" />
    </fragment>
    <fragment
        android:id="@ id/homeFragment"
        android:name="my.app.ui.home.HomeFragment"
        android:label="fragment_home"
        tools:layout="@layout/fragment_home">
        <action
            android:id="@ id/action_homeFragment_to_detailFragment"
            app:destination="@id/detailFragment" />
    </fragment>
    <fragment
        android:id="@ id/favoriteFragment"
        android:name="my.app.ui.favorite.FavoriteFragment"
        android:label="fragment_favorite"
        tools:layout="@layout/fragment_favorite" />
    <fragment
        android:id="@ id/searchFragment"
        android:name="my.app.ui.search.SearchFragment"
        android:label="fragment_search"
        tools:layout="@layout/fragment_search" />
    <fragment
        android:id="@ id/detailFragment"
        android:name="my.app.ui.detail.DetailFragment"
        android:label="fragment_detail"
        tools:layout="@layout/fragment_detail" />
</navigation>

我該如何解決？

uj5u.com熱心網友回復：

看起來由于某種原因findController()仍在使用目的地。RegisterFragment

我猜根本原因是因為執行緒混淆findController()了它仍然認為你在RegisterFragment.

作為深入挖掘執行緒管理之前的解決方法，您可以嘗試對導航布局檔案中的actionSplashToHomea進行操作。Global Action只需將該動作移到fragment標簽之外，然后此導航檔案中的任何片段都可以使用此動作。

<?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/nav_main"
    app:startDestination="@id/splashFragment">

    <fragment
        android:id="@ id/splashFragment"
        android:name="my.app.ui.splash.SplashFragment"
        android:label="fragment_splash"
        tools:layout="@layout/fragment_splash">

        <action
            android:id="@ id/actionSplashToRegister"
            app:destination="@id/registerFragment"
            app:enterAnim="@anim/nav_default_enter_anim"
            app:exitAnim="@anim/nav_default_exit_anim"
            app:popEnterAnim="@anim/nav_default_pop_enter_anim"
            app:popExitAnim="@anim/nav_default_pop_exit_anim" />
    </fragment>

     <action
        android:id="@ id/action_global_splash_ToHome"
        app:destination="@id/homeFragment"
        app:enterAnim="@anim/nav_default_enter_anim"
        app:exitAnim="@anim/nav_default_exit_anim"
        app:popEnterAnim="@anim/nav_default_pop_enter_anim"
        app:popExitAnim="@anim/nav_default_pop_exit_anim"/>

    <fragment
        android:id="@ id/registerFragment"
        android:name="my.app.ui.register.RegisterFragment"
        android:label="fragment_register"
        tools:layout="@layout/fragment_register">
        <action
            android:id="@ id/actionRegisterToHome"
            app:destination="@id/homeFragment" />
    </fragment>
    <fragment
        android:id="@ id/homeFragment"
        android:name="my.app.ui.home.HomeFragment"
        android:label="fragment_home"
        tools:layout="@layout/fragment_home">
        <action
            android:id="@ id/action_homeFragment_to_detailFragment"
            app:destination="@id/detailFragment" />
    </fragment>
    <fragment
        android:id="@ id/favoriteFragment"
        android:name="my.app.ui.favorite.FavoriteFragment"
        android:label="fragment_favorite"
        tools:layout="@layout/fragment_favorite" />
    <fragment
        android:id="@ id/searchFragment"
        android:name="my.app.ui.search.SearchFragment"
        android:label="fragment_search"
        tools:layout="@layout/fragment_search" />
    <fragment
        android:id="@ id/detailFragment"
        android:name="my.app.ui.detail.DetailFragment"
        android:label="fragment_detail"
        tools:layout="@layout/fragment_detail" />
</navigation>

無需更改 Splashfragment 中的代碼，仍可使用findNavController().navigate(R.id.action_global_splash_ToHome)

轉載請註明出處，本文鏈接：https://www.uj5u.com/qianduan/440828.html

標籤：安卓科特林安卓架构导航

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