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我刚刚使用“活动抽屉活动模板”在 Android Studio 4.0 中创建了一个新项目。模板创建了一个主活动控制器和三个片段。该应用程序从“主页”片段开始。菜单项点击导航到不同的片段。我搜索了该项目，但找不到 onNavigationItemSelected 或其他侦听器的任何实现。

在哪里处理菜单选择？

这是 MainActivity.kt 中的代码

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

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1 回答 1

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在顶部你需要这样写

    class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener {

一旦你像这样写了它，你应该能够覆盖这个onNavigationItemSelected函数。

于 2020-06-13T15:23:20.517 回答