android - 如何让向上按钮返回而不是打开抽屉导航

Question

我成功地在我的应用程序中实现了一个抽屉导航，将菜单的每个项目链接到一个 fragment 。目标 fragment 隐藏了 DrawerToggle 并显示向上按钮(即箭头图标)，但无论出于何种原因，如果我单击它，它会打开抽屉并且我无法返回到前一个 fragment 。我必须按后退按钮才能做到。我怎样才能改变这种行为？是否可以在不在每个 fragment 中添加代码的情况下解决此问题？

我使用的是:

导航组件

一个 Activity ，一些 fragment

工具栏

AppBarConfiguration

主 Activity

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        // Setup FTUE conditional navigation
        setupNavigation()

        setupNavigationDrawer()

        appBarConfiguration =
            AppBarConfiguration(
                setOf(R.id.overviewFragment, R.id.registrationFragment,
                       R.id.registrationParamFragment), drawerLayout)
        setupActionBarWithNavController(navController, appBarConfiguration)
        findViewById<NavigationView>(R.id.nav_view)
            .setupWithNavController(navController)
    }

    /**
     * Set the toolbar, set the drawerLayout, set the drawerToggle
     */
    private fun setupNavigationDrawer() {
        toolbar = findViewById(R.id.toolbar)

        setSupportActionBar(toolbar)

        drawerLayout = (findViewById<DrawerLayout>(R.id.drawer_layout))
            .apply {
                setStatusBarBackground(R.color.colorPrimaryDark)
            }
        drawerToggle = ActionBarDrawerToggle(this, drawerLayout, toolbar, R.string.open, R.string.close)
        drawerToggle.setDrawerIndicatorEnabled(true)
        drawerToggle.syncState()

        drawerLayout.addDrawerListener(drawerToggle)

    }

    override fun onPostCreate(savedInstanceState: Bundle?, persistentState: PersistableBundle?) {
        super.onPostCreate(savedInstanceState, persistentState)
        drawerToggle.syncState()
    }

    /**
     * Ensures that the drawer is closed
     * before the app switches back to the previous fragment
     */
    override fun onBackPressed() {
        if (drawerLayout.isDrawerOpen(GravityCompat.START)) {
            drawerLayout.closeDrawer(GravityCompat.START)
        } else {
            super.onBackPressed()
        }
    }
}

完整存储库: Github

Answer 1

您需要使用导航 Controller 设置您的工具栏:

toolbar.setupWithNavController(findNavController(R.id.nav_host_fragment),findViewById(R.id.full_drawer_layout))

有关于此的更多信息 here .