片段不使用 FragmentContainerView 切换

Posted 2023-04-15

【中文标题】片段不使用 FragmentContainerView 切换

【英文标题】：Fragment not switching using FragmentContainerView

【发布时间】：2021-12-26 16:38:34

【问题描述】：

我只是想将 bottomNavigation 与导航组件一起使用。我尝试了多种方法，但片段没有切换。只有底部导航显示的

我有一个使用片段而不是 FragmentContainerView 的正在运行的示例。但是我不知道为什么使用最新的技术太复杂了 仪表板活动

@androidEntryPoint
class DashboardActivity : PBActivity(R.layout.activity_dashboard) 
    val binding: ActivityDashboardBinding by viewbind()
    override fun onCreate(savedInstanceState: Bundle?) 
        super.onCreate(savedInstanceState)

        val appBarConfiguration: AppBarConfiguration = AppBarConfiguration.Builder(
            R.id.rankingFragment, R.id.homeFragment, R.id.profileFragment
        ).build()

        setSupportActionBar(binding.toolbar)
        val navHostFragment =
            supportFragmentManager.findFragmentById(R.id.nav_host_fragment) as NavHostFragment
        val navController = navHostFragment.navController
        /*val navView = findViewById<BottomNavigationView>(R.id.bottom_nav)
        NavigationUI.setupWithNavController(navView,navController)*/

        ///binding.navigationBb.setupWithNavController(navController)
        ///binding.toolbar.setupWithNavController(navController,null)
        //binding.navHostFragment.s
        binding.toolbar.setupWithNavController(navController,appBarConfiguration)
        ///binding.bottomNav.setupWithNavController(navController)

        NavigationUI.setupWithNavController(binding.bottomNav, navController)
        ///NavigationUI.setupWithNavController(binding.bottomNav,navController)
    
 

activity_dashboard.xml

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

    <data>

    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_
        android:layout_>

        <androidx.appcompat.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_
            android:layout_
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintTop_toTopOf="parent">

        </androidx.appcompat.widget.Toolbar>

        <androidx.fragment.app.FragmentContainerView
            android:id="@+id/nav_host_fragment"
            android:name="androidx.navigation.fragment.NavHostFragment"
            android:layout_
            android:layout_
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintBottom_toBottomOf="parent"
            app:defaultNavHost="true"
            app:navGraph="@navigation/nav_graph" />

        <com.google.android.material.bottomnavigation.BottomNavigationView
            android:id="@+id/bottom_nav"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintBottom_toBottomOf="parent"
            android:layout_
            app:menu="@menu/dashboard_nav_menu"
            android:background="?android:attr/windowBackground"
            android:layout_ />

    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>

nav_graph.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/nav_graph"
    app:startDestination="@id/homeFragment">

    <fragment
        android:id="@+id/homeFragment"
        tools:layout="@layout/fragment_home"
        android:name="uk.co.planetbeyond.game_show_app.presentation.ui.main.fragments.HomeFragment"
        android:label="HomeFragment" />
    <fragment
        android:id="@+id/rankingFragment"
        tools:layout="@layout/fragment_ranking"
        android:name="uk.co.planetbeyond.game_show_app.presentation.ui.main.fragments.RankingFragment"
        android:label="RankingFragment" />
    <fragment
        android:id="@+id/profileFragment"
        tools:layout="@layout/fragment_profile"
        android:name="uk.co.planetbeyond.game_show_app.presentation.ui.main.fragments.ProfileFragment"
        android:label="ProfileFragment" />
</navigation>

dashboard_nav_menu.xml

 <?xml version="1.0" encoding="utf-8"?>
    <menu xmlns:android="http://schemas.android.com/apk/res/android">
    
        <item
            android:id="@+id/rankingFragment"
            android:icon="@drawable/rankings_button_selected"
            android:title="Ranking" />
        <item
            android:id="@+id/homeFragment"
            android:icon="@drawable/home_button_selected"
            android:title="@string/title_home" />
        <item
            android:id="@+id/profileFragment"
            android:icon="@drawable/profile_icon_selected"
            android:title="Profile" />
    </menu>

【参考方案1】：

问题不在于导航组件，您的代码看起来不错；但是您的主布局的大小为 0：

您需要设置根布局以匹配父级：

<androidx.constraintlayout.widget.ConstraintLayout
        android:layout_
        android:layout_>
...

旁注：片段将在工具栏后面绘制，因为它约束到父顶部边缘；底部也一样。

要将此约束修复到工具栏：

在FragmentContainerView 中替换：

app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"

与：

app:layout_constraintTop_toBottomOf="@+id/toolbar"
app:layout_constraintBottom_toTopOf="@+id/bottom_nav"

【讨论】：

还是不行

仍然没有显示任何片段？