BottomNavigationView与navgraph再次加载片段 [英] BottomNavigationView with navgraph loading fragment again

问题描述

我将BottomNavigationView与nav-graph一起使用 下面是我的代码

I am using BottomNavigationView with nav-graph Below is my code

在MainActivity.class

navController = Navigation.findNavController(this, R.id.mainFragment);

    bottomNavigation.setOnNavigationItemSelectedListener(menuItem -> {
        switch (menuItem.getItemId()){
            case R.id.home:
                navController.navigate(R.id.exploreFragment);
                return true;
            case R.id.events:
                navController.navigate(R.id.eventsFragment);
                return true;
            case R.id.stories:
                navController.navigate(R.id.storiesFragment);
                return true;
        }
        return false;
    });

activity_main.xml

activity_main.xml

<fragment
    android:id="@+id/mainFragment"
    app:defaultNavHost="true"
    android:name="androidx.navigation.fragment.NavHostFragment"
    android:layout_width="0dp"
    android:layout_height="0dp"
    app:layout_constraintBottom_toTopOf="@+id/bottomNavigation"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:navGraph="@navigation/nav_home"/>

<com.google.android.material.bottomnavigation.BottomNavigationView
    android:layout_width="match_parent"
    app:itemIconTint="@drawable/bottom_navigation_color"
    app:itemTextColor="@drawable/bottom_navigation_color"
    android:background="@color/grey_50"
    android:id="@+id/bottomNavigation"
    app:menu="@menu/bottom_navigation"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    android:layout_height="wrap_content"/>

<include
    layout="@layout/toolbar"
    android:id="@+id/toolbar"/>

nav_home.xml

nav_home.xml

<fragment
    android:id="@+id/exploreFragment"
    android:name="com.decathlon.allforsport.home.explore.ExploreFragment"
    tools:layout="@layout/fragment_explore" />
<fragment
    android:id="@+id/eventsFragment"
    android:name="com.decathlon.allforsport.home.events.EventsFragment"
    tools:layout="@layout/fragment_stories" />
<fragment
    android:id="@+id/storiesFragment"
    android:name="com.decathlon.allforsport.home.stories.StoriesFragment"
    tools:layout="@layout/fragment_stories" />

所以问题是当我在BottomNavigationView中点击Home时，它会一次又一次地重新加载片段.我尝试了很多方法，但没有成功.

So problem is when I tap on Home in BottomNavigationView, it reloads the fragment again and again. I tried many ways, but no success.

推荐答案

由于使用的是navigation controller，因此可以删除setOnNavigationItemSelectedListener函数.

Since you are using navigation controller, you can remove setOnNavigationItemSelectedListener function.

在bottom_navigation菜单中，确保定义的项目ID与在nav graph中定义的ID相同.

In bottom_navigation menu, make sure you define the item id same as the id you defined in nav graph.

您需要这些代码才能使底部导航栏起作用

And you need those code to make the bottom navigation bar works

setupActionBarWithNavController(navController!!)
bottomNavigation.setupWithNavController(navController!!)

修改

对于androidx

For androidx

NavigationUI.setupWithNavController(bottomNavigation, 
Navigation.findNavController(this, R.id.mainFragment))

这篇关于BottomNavigationView与navgraph再次加载片段的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！