与导航抽屉一起使用时，工具栏后退按钮不起作用 [英] Toolbars Back button not working when using with navigation drawer

问题描述

下面是代码

我已经用 AppbarConfiguraion 定义了我所有的顶级目的地.

I have defined all my top level destinations with AppbarConfiguraion.

class MainActivity : DaggerAppCompatActivity(), NavigationView.OnNavigationItemSelectedListener {

    lateinit var navController: NavController
    lateinit var binding: MainActivityBinding
    lateinit var appBarConfiguration: AppBarConfiguration

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = DataBindingUtil.setContentView(this, R.layout.activity_main)
        navController = findNavController(R.id.navigation)
        setSupportActionBar(binding.toolbar)
        supportActionBar!!.setDisplayShowHomeEnabled(true)

        appBarConfiguration = AppBarConfiguration(
            setOf(
                R.id.homeFragment,
                R.id.bulletinsFragment,
                R.id.serviceFragment,
                R.id.paymentsFragment,
                R.id.feedBackFragment,
                R.id.formsFragment,
                R.id.surveysFragment
            ),
            drawer_layout)
        setupActionBarWithNavController(
            this, navController, appBarConfiguration
            )

        val toggle = ActionBarDrawerToggle(
            this,
            drawer_layout,
            binding.toolbar,
            R.string.navigation_drawer_open,
            R.string.navigation_drawer_close
        )
        drawer_layout.addDrawerListener(toggle)
        toggle.syncState()
        sideNV.setNavigationItemSelectedListener(this)
    }

    override fun onBackPressed() {
        if ((drawer_layout as DrawerLayout).isDrawerOpen(GravityCompat.START)) {
            (drawer_layout as DrawerLayout).closeDrawer(GravityCompat.START)
        } else {
            findNavController(R.id.navigation).navigateUp()
        }
    }

    override fun onNavigationItemSelected(item: MenuItem): Boolean {

        when (item.itemId) {
            R.id.nav_home, R.id.nav_service, R.id.nav_payments, R.id.nav_forms, R.id.nav_bulletins,
            R.id.nav_surveys, R.id.nav_feedbacks -> {
                navController.navigate(item.itemId)
            }
        }
        (drawer_layout as DrawerLayout).closeDrawer(GravityCompat.START)
        return true
    }

    override fun onSupportNavigateUp() = findNavController(R.id.navigation).navigateUp()
}

当从顶级片段移动到其他片段时，会显示后退箭头，但单击它会打开抽屉本身.单击系统后退按钮时，它工作正常.

When moving from the top level fragments to other fragments the back arrow is shown but when on clicking it opens the drawer itself. When on clicking the system back button it's working fine.

清单

<activity
        android:name=".home.MainActivity"
        android:label="@string/app_name"
        android:parentActivityName=".home.MainActivity"
        android:theme="@style/AppTheme.NoActionBar">
</activity>

推荐答案

class MainActivity : DaggerAppCompatActivity(), NavigationView.OnNavigationItemSelectedListener {

    lateinit var navController: NavController
    lateinit var binding: MainActivityBinding
    lateinit var appBarConfiguration: AppBarConfiguration

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = DataBindingUtil.setContentView(this, R.layout.activity_main)
        navController = findNavController(R.id.navigation)
        setSupportActionBar(binding.toolbar)
        supportActionBar!!.setDisplayShowHomeEnabled(true)

        appBarConfiguration = AppBarConfiguration(
            setOf(
                R.id.homeFragment,
                R.id.bulletinsFragment,
                R.id.serviceFragment,
                R.id.paymentsFragment,
                R.id.feedBackFragment,
                R.id.formsFragment,
                R.id.surveysFragment
            ),
            drawer_layout
        )
        setupActionBarWithNavController(
            this, navController, appBarConfiguration
        )

        val toggle = ActionBarDrawerToggle(
            this,
            drawer_layout,
            binding.toolbar,
            R.string.navigation_drawer_open,
            R.string.navigation_drawer_close
        )
        drawer_layout.addDrawerListener(toggle)
        toggle.syncState()
        sideNV.setNavigationItemSelectedListener(this)
        toolbar?.setNavigationOnClickListener {
            findNavController(R.id.navigation).navigateUp(appBarConfiguration)
        }
    }

    override fun onBackPressed() {
        if ((drawer_layout as DrawerLayout).isDrawerOpen(GravityCompat.START)) {
            (drawer_layout as DrawerLayout).closeDrawer(GravityCompat.START)
        } else {
            super.onBackPressed()
        }
    }

    override fun onNavigationItemSelected(item: MenuItem): Boolean {

        when (item.itemId) {
            R.id.nav_home, R.id.nav_service, R.id.nav_payments, R.id.nav_forms, R.id.nav_bulletins,
            R.id.nav_surveys, R.id.nav_feedbacks -> {
                navController.navigate(item.itemId)
            }
        }
        (drawer_layout as DrawerLayout).closeDrawer(GravityCompat.START)
        return true
    }

    override fun onSupportNavigateUp() = findNavController(R.id.navigation).navigateUp()
}

我刚刚更改了我的代码并添加了工具栏 NavigationOnClickListener 并且在那个监听器中我刚刚添加了 navigateUp(appBarConfiguration).onBackPressed() 也有轻微的变化在我之前的代码中，即使我们位于堆栈中的最后一个片段，它也不会关闭应用程序

i just changed my code and added toolbar NavigationOnClickListener and in that listener i just added navigateUp(appBarConfiguration).Also there is a slight change in the onBackPressed() as in my previous code it will not close the app even if we are at the last fragment in the stack

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