在最新的Kotlin导航抽屉活动模板中没有onNavigationItemSelected的实现。

Question

我刚刚在Android studio 4.0中使用 "Activity Drawer活动模板 "创建了一个新项目。通过模板创建了一个主活动控制器和三个片段。应用程序在 "主页 "片段上启动。菜单项点击导航到不同的片段.我已经搜索了项目，找不到任何onNavigationItemSelected或其他监听器的实现。

菜单选择的处理在哪里？

下面是MainActivity.kt的代码。

class MainActivity : AppCompatActivity() {

    private lateinit var appBarConfiguration: AppBarConfiguration

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        val toolbar: Toolbar = findViewById(R.id.toolbar)
        setSupportActionBar(toolbar)

        val drawerLayout: DrawerLayout = findViewById(R.id.drawer_layout)
        val navView: NavigationView = findViewById(R.id.nav_view)
        val navController = findNavController(R.id.nav_host_fragment)
        // Passing each menu ID as a set of Ids because each
        // menu should be considered as top level destinations.
        appBarConfiguration = AppBarConfiguration(setOf(
                R.id.nav_home, R.id.nav_gallery, R.id.nav_slideshow), drawerLayout)
        setupActionBarWithNavController(navController, appBarConfiguration)
        navView.setupWithNavController(navController)
    }

    override fun onCreateOptionsMenu(menu: Menu): Boolean {
        // Inflate the menu; this adds items to the action bar if it is present.
        menuInflater.inflate(R.menu.main, menu)
        return true
    }

    override fun onSupportNavigateUp(): Boolean {
        val navController = findNavController(R.id.nav_host_fragment)
        return navController.navigateUp(appBarConfiguration) || super.onSupportNavigateUp()
    }
}

谢谢你

Answer 1

在顶部，你需要这样写

    class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener {

一旦你这样写了，你应该能够覆盖掉 onNavigationItemSelected 职能。