onNavigationItemSelectedListener

onNavigationItemSelectedListener

我是Kotlin开发的新手。我试图做一个BottomNavigationView,一切正常,但是当我想为ItemSelected侦听器创建BottomNavigationView变量时,出现以下错误:

Function invocation 'BottomNavigationView(...)' expected.


但是在我的教程中,它的声明如下:BottomNavigationView bottomNav

所以怎么了,我不明白..
你能帮我吗 ?

最佳答案

为bottomViewListener声明一个全局变量

'onNavigationItemSelectedListener'

在onCreate()的bottomView中初始化和设置侦听器

val navView:BottomNavigationView = findViewById(R.id.nav_view)
navView.setOnNavigationItemSelectedListener(onNavigationItemSelectedListener)

private val onNavigationItemSelectedListener = BottomNavigationView.OnNavigationItemSelectedListener { item ->
        when (item.itemId) {
            R.id.navigation_home -> {
                return@OnNavigationItemSelectedListener true
            }
            R.id.navigation_deals -> {
                return@OnNavigationItemSelectedListener true
            }

        }
        false
    }

10-08 11:27