如果使用导航组件在每个片段中设置工具栏，如何删除顶层片段工具栏中的后退按钮？

问题描述

我试图阅读

解决方案

我终于得到了答案。我需要在每个顶级片段中设置 appBarConfiguration

以便在我的 HomeFragment 和 SearchFragment 中，您应该这样

  val工具栏= view.findViewById< androidx.appcompat.widget.Toolbar>（R.id.toolbar2）
 val appBarConfiguration = AppBarConfiguration（setOf（
 R.id.destination_home，
 R. id.destination_search）
）
 
 val navHostFragment = NavHostFragment.findNavController（this）; 
 NavigationUI.setupWithNavController（工具栏，navHostFragment，appBarConfiguration）
  

要使用 AppBarConfiguration 类，您需要 navigation-ui-ktx 工件，并且在gradle应用中，还需要使用此编译选项和kotlin选项

  android {
 
 
 compileOptions {
 sourceCompatibility JavaVersion.VERSION_1_8 
 targetCompatibility JavaVersion .VERSION_1_8 
} 
 
 kotlinOptions {
 jvmTarget = JavaVersion.VERSION_1_8.toString（）
} 
 
} 
  

I have tried to read this but my problem is little bit different.

I need some different toolbars, so according the documentation from here , I need to set the toolbar in each of my fragment not in my MainActivity.

so I set the toolbar in each xml of my fragment. and then in each fragment I use this code to set the toolbar

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        val toolbar = view.findViewById<androidx.appcompat.widget.Toolbar>(R.id.toolbar3)

        val navHostFragment = NavHostFragment.findNavController(this);
        NavigationUI.setupWithNavController(toolbar, navHostFragment)


    }

but I have back button in top level fragment of my bottom navigation view like the image below. I am confused how to pass appBarConfiguration if I set the toolbar from my fragment not from my MainActivity

解决方案

I finally get the answer. I need to set appBarConfiguration in EACH top level fragment

so in my HomeFragment and in SearchFragment, you should it like this

val toolbar = view.findViewById<androidx.appcompat.widget.Toolbar>(R.id.toolbar2)
val appBarConfiguration = AppBarConfiguration(setOf(
    R.id.destination_home,
    R.id.destination_search)
)

val navHostFragment = NavHostFragment.findNavController(this);
NavigationUI.setupWithNavController(toolbar, navHostFragment,appBarConfiguration)

to use AppBarConfiguration class , you need navigation-ui-ktx artifact and also in gradle app you use pass this compile options and kotlin options

android {


    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }

    kotlinOptions {
        jvmTarget = JavaVersion.VERSION_1_8.toString()
    }

}

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