Android 启动活动功能中的问题在哪里

我是科特林开发公司的新员工。我正试图从

main

活动启动一个新活动，但它显示的唯一内容是在toast消息之后显示一条空白消息。但我真的不明白问题从何而来

以下是

main活动

：

class MainActivity : AppCompatActivity() {

    private fun replaceFragment(fragment: Fragment){
        val fragmentTransaction = supportFragmentManager.beginTransaction()
        fragmentTransaction.replace(R.id.fragment_container, fragment)
        fragmentTransaction.commit()
    }

    private val onNavigationItemSelectedListener = BottomNavigationView.OnNavigationItemSelectedListener {
        item -> when (item.itemId) {
            R.id.nav_home -> {
                //replaceFragment(HomeFragment())
                return@OnNavigationItemSelectedListener true
            }
            R.id.nav_search -> {
                replaceFragment(SearchFragment())
                return@OnNavigationItemSelectedListener true
            }
            R.id.nav_person -> {
                replaceFragment(ProfileFragment())
                return@OnNavigationItemSelectedListener true
            }
            R.id.nav_favorites -> {
                replaceFragment(FavoritesFragment())
                return@OnNavigationItemSelectedListener true
            }

        }
        false
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val navView: BottomNavigationView = findViewById(R.id.bottom_navigation)
        navView.setOnNavigationItemSelectedListener(onNavigationItemSelectedListener)
        navView.setSelectedItemId(R.id.nav_home)

        if (!imgurClient.isConnected) {
            Toast.makeText(applicationContext,"You are not connected.",Toast.LENGTH_SHORT).show()
            val intentToWebView = Intent(this, LoginActivity::class.java)
            startActivity(intentToWebView)
        }

    }
}

eclass LoginActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?, persistentState: PersistableBundle?) {
        super.onCreate(savedInstanceState, persistentState)
        setContentView(R.layout.activity_login)
    }
}

以下是

LoginActivity

：

class MainActivity : AppCompatActivity() {

    private fun replaceFragment(fragment: Fragment){
        val fragmentTransaction = supportFragmentManager.beginTransaction()
        fragmentTransaction.replace(R.id.fragment_container, fragment)
        fragmentTransaction.commit()
    }

    private val onNavigationItemSelectedListener = BottomNavigationView.OnNavigationItemSelectedListener {
        item -> when (item.itemId) {
            R.id.nav_home -> {
                //replaceFragment(HomeFragment())
                return@OnNavigationItemSelectedListener true
            }
            R.id.nav_search -> {
                replaceFragment(SearchFragment())
                return@OnNavigationItemSelectedListener true
            }
            R.id.nav_person -> {
                replaceFragment(ProfileFragment())
                return@OnNavigationItemSelectedListener true
            }
            R.id.nav_favorites -> {
                replaceFragment(FavoritesFragment())
                return@OnNavigationItemSelectedListener true
            }

        }
        false
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val navView: BottomNavigationView = findViewById(R.id.bottom_navigation)
        navView.setOnNavigationItemSelectedListener(onNavigationItemSelectedListener)
        navView.setSelectedItemId(R.id.nav_home)

        if (!imgurClient.isConnected) {
            Toast.makeText(applicationContext,"You are not connected.",Toast.LENGTH_SHORT).show()
            val intentToWebView = Intent(this, LoginActivity::class.java)
            startActivity(intentToWebView)
        }

    }
}

eclass LoginActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?, persistentState: PersistableBundle?) {
        super.onCreate(savedInstanceState, persistentState)
        setContentView(R.layout.activity_login)
    }
}

Activity\u login.xml

包含一个

textview

，它以白色显示文本，背景为紫色

---

您能帮我吗？

您在

登录活动中重写了错误的方法。应该是：

class LoginActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState, persistentState)
        setContentView(R.layout.activity_login)
    }
}

您必须重写正确的onCreate方法。应该是

class LoginActivity : AppCompatActivity() {

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_login)
 }
}

您必须在不使用
PersistableBundle
作为第二个参数的情况下重写正确的：

class LoginActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_login)
    }
}