如何使用“addOnDestinationChangedListener”删除底部导航和工具栏

如何解决如何使用“addOnDestinationChangedListener”删除底部导航和工具栏

我正在开发一个需要登录和/或注册的应用程序。我还使用了自定义工具栏和底部导航栏，我想从 login 和 create account 片段中删除这些。通过使用下面的工具栏代码，我成功地将它们从登录片段中删除：

navController.addOnDestinationChangedListener { _,destination,_ ->
            toolbar.visibility = if (destination.id == R.id.loginFragment) {
                View.GONE
            } else {
                View.VISIBLE
            }
        }

以及底部导航的类似代码：

navController.addOnDestinationChangedListener { _,_ ->
            bottomNavigationView.visibility = if (destination.id == R.id.loginFragment) {
                View.GONE
            } else {
                View.VISIBLE
            }
        }

我想知道的是，就像我从登录片段中隐藏了工具栏一样。我怎样才能从另一个片段中删除它？

MainActivity.KT：

package com.example.integratedmodulateoroperationroom

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.Menu
import android.view.MenuItem
import android.view.View
import androidx.navigation.NavController
import androidx.navigation.fragment.NavHostFragment
import androidx.navigation.fragment.findNavController
import androidx.navigation.ui.*
import com.google.android.material.bottomnavigation.BottomNavigationView
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {
    private lateinit var navController: NavController
    private lateinit var appBarConfiguration: AppBarConfiguration
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

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

        appBarConfiguration = AppBarConfiguration(
            setof(R.id.homeFragment,R.id.loginFragment),drawer_layout
        )

        setSupportActionBar(toolbar)
        setupActionBarWithNavController(navController,appBarConfiguration)

        navController.addOnDestinationChangedListener { _,_ ->
            toolbar.visibility = if (destination.id == R.id.loginFragment) {
                View.GONE
            } else {
                View.VISIBLE
            }
        }

        bottom_nav.setupWithNavController(navController)
        val bottomNavigationView = findViewById<BottomNavigationView>(R.id.bottom_nav)

        navController.addOnDestinationChangedListener { _,_ ->
            bottomNavigationView.visibility = if (destination.id == R.id.loginFragment) {
                View.GONE
            } else {
                View.VISIBLE
            }
        }

        nav_view.setupWithNavController(navController)
    }

    override fun onCreateOptionsMenu(menu: Menu?): Boolean {
        menuInflater.inflate(R.menu.options_menu,menu)
        return true
    }

    override fun onoptionsItemSelected(item: MenuItem): Boolean {
        return item.onNavDestinationSelected(navController) || super.onoptionsItemSelected(item)
    }

    override fun onSupportNavigateUp(): Boolean {
        return navController.navigateUp(appBarConfiguration) || super.onSupportNavigateUp()
    }
}

activity_main.XML：

<?xml version="1.0" encoding="utf-8"?>
<androidx.drawerlayout.widget.DrawerLayout
    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/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

    <androidx.appcompat.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/design_default_color_primary"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />

    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/nav_host_fragment"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:defaultNavHost="true"
        app:layout_constraintBottom_toTopOf="@+id/bottom_nav"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/toolbar"
        app:navGraph="@navigation/nav_graph" />

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/bottom_nav"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:menu="@menu/bottom_nav_menu" />

    </androidx.constraintlayout.widget.ConstraintLayout>

    <com.google.android.material.navigation.NavigationView
        android:id="@+id/nav_view"
        android:layout_gravity="start"
        app:menu="@menu/drawer_nav_menu"
        android:layout_width="wrap_content"
        android:layout_height="match_parent" />

</androidx.drawerlayout.widget.DrawerLayout>

解决方法

在尝试了很多东西之后，我得到了一个解决方案......没有太多要做的事情，只需稍微更改代码就可以了。 对于工具栏：

navController.addOnDestinationChangedListener { _,destination,_ ->
            when(destination.id) {
                R.id.loginFragment,R.id.createAccountFragment ->
                    toolbar.visibility = View.GONE
                else -> toolbar.visibility = View.VISIBLE
            }
        }

同样，对于底部导航视图，我们使用：

navController.addOnDestinationChangedListener { _,R.id.createAccountFragment ->
                    bottomNavigationView.visibility = View.GONE
                else -> bottomNavigationView.visibility = View.VISIBLE
            }
        }