无法从一个片段移动到另一个片段

Question

我正在尝试设置一个 activity 和一个 fragment 以及一个 recyclerview 和一个底部导航菜单。当我点击 'Dashboard' 时，我可以看到进度条并更新来自 Firestore 的数据，但是当我点击测验时，我看不到进度条或新数据。我所看到的只是相同的数据。我认为它不会移动到其他片段。

作为初学者，我不知道 fragments 和 recyclerview 的实际工作原理，我是在在线人员和资源的帮助下完成的。我不知道问题出在哪里。如果需要，我可以提供更多代码。

注意：我没有收到任何错误。

bottom_nav_menu.xml

    <?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">

    <item
        android:id="@+id/navigation_dashboard"
        android:icon="@drawable/ic_vector_dashboard"
        android:title="Dashboard" />

    <item
        android:id="@+id/navigation_quizzes"
        android:icon="@drawable/ic_vector_quizzes"
        android:title="Quizzes" />

</menu>

mobile_navigation.xml

    <?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/mobile_navigation"
    app:startDestination="@+id/navigation_dashboard">

    <fragment
        android:id="@+id/navigation_dashboard"
        android:name="com.example.quiz.ui.fragments.DashboardFragment"
        android:label="@string/title_dashboard"
        tools:layout="@layout/fragment_dashboard" />

    <fragment
        android:id="@+id/navigation_quiz"
        android:name="com.example.quiz.ui.fragments.QuizFragment"
        android:label="@string/title_products"
        tools:layout="@layout/fragment_quiz" />

</navigation>

activity_dashboard.xml

    <?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/nav_view"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="0dp"
        android:layout_marginEnd="0dp"
        android:background="@drawable/app_gradient_color_background"
        app:itemIconTint="@color/colorWhite"
        app:itemTextColor="@color/colorWhite"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:menu="@menu/bottom_nav_menu" />


    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/nav_host_fragment"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:defaultNavHost="true"
        app:layout_constraintBottom_toTopOf="@id/nav_view"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.0"
        app:navGraph="@navigation/mobile_navigation" />


</androidx.constraintlayout.widget.ConstraintLayout>

fragment_dashboard.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/white"
    tools:context=".ui.fragments.DashboardFragment">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rv_dashboard_items"
        tools:listitem="@layout/item_list_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/tv_no_dashboard_items_found"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:text="no_dashboard_item_found"
        android:textAlignment="center"
        android:textSize="20sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

fragment_quiz.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/white"
    tools:context=".ui.fragments.QuizFragment">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rvQuizzesFrag"
        tools:listitem="@layout/item_list_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/tv_no_products_found"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:text="NO QUIZZES TODAY"
        android:textAlignment="center"
        android:textSize="30sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

DashboardActivity.kt

package com.example.quiz.ui.activities

import android.os.Bundle
import androidx.core.content.ContextCompat
import androidx.navigation.findNavController
import androidx.navigation.fragment.NavHostFragment
import androidx.navigation.ui.AppBarConfiguration
import androidx.navigation.ui.setupActionBarWithNavController
import androidx.navigation.ui.setupWithNavController
import com.google.android.material.bottomnavigation.BottomNavigationView
import com.example.quiz.R

class DashboardActivity : BaseActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_dashboard)
     
        supportActionBar!!.setBackgroundDrawable(
            ContextCompat.getDrawable(
                this@DashboardActivity,
                R.drawable.app_gradient_color_background
            )
        )


        val navView: BottomNavigationView = findViewById(R.id.nav_view)

        val navHostFragment = supportFragmentManager.findFragmentById(R.id.nav_host_fragment) as NavHostFragment
        val navController = navHostFragment.navController

        val appBarConfiguration = AppBarConfiguration(
            setOf(
                R.id.navigation_quiz,
                R.id.navigation_dashboard
            )
        )
        setupActionBarWithNavController(navController, appBarConfiguration)

        navView.setupWithNavController(navController)
    }

    override fun onBackPressed() {
        doubleBackToExit()
    }
}

你能告诉我这些 R.id.navigation_quiz、R.id.navigation_dashboard 应该指的是什么地方吗？无论是 bottom_nav_menu.xml 还是 mobile_navigation.xml.

Answer 1

如果您认为它没有移动到 Quiz Fragment 那么可能是因为您的 BottomNavigation 没有正常工作....

要使底部导航与 Nav Controller 一起正常工作，bottom_nav_menu.xml 和 moile_navigation.xml 中的 id's 项必须相同

在你的情况下，仪表板的 id 在 bottom_nav_menu.xml 和 moile_navigation.xml 中是相同的，但对于测验，这两个文件中的 id 是不同的，它是 @+id/navigation_quizzes在 bottom_nav_menu.xml 和 moile_navigation.xml 中是 @+id/navigation_quiz

使两个文件中的id相同

bottom_nav_menu.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android">

    <item
        android:id="@+id/navigation_dashboard"
        android:icon="@drawable/ic_vector_dashboard"
        android:title="Dashboard" />

    <item
        android:id="@+id/navigation_quiz"
        android:icon="@drawable/ic_vector_quiz"
        android:title="Quizzes" />
</menu>

moile_navigation.xml

<?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/mobile_navigation"
    app:startDestination="@+id/navigation_dashboard">

    <fragment
        android:id="@+id/navigation_dashboard"
        android:name="com.example.quiz.ui.fragments.DashboardFragment"
        android:label="@string/title_dashboard"
        tools:layout="@layout/fragment_dashboard" />

    <fragment
        android:id="@+id/navigation_quiz"
        android:name="com.example.quiz.ui.fragments.QuizFragment"
        android:label="@string/title_products"
        tools:layout="@layout/fragment_quiz" />

</navigation>

无法从一个片段移动到另一个片段

Unable to move from one fragment to another

android-fragments

kotlin

android-recyclerview

android-navigation-bar