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底部导航栏未显示-Android_Android_Kotlin - Fatal编程技术网

底部导航栏未显示-Android

底部导航栏未显示-Android,android,kotlin,Android,Kotlin,我正在学习Android,我正在尝试实现底部导航栏。在主活动中,导航栏出现,但不在模拟器中。下面是MainActivity和ActivityMain文件。谢谢你的帮助 MainActivity.kt package com.example.androidapp import android.os.Bundle import androidx.appcompat.app.AppCompatActivity import androidx.navigation.NavController

我正在学习Android,我正在尝试实现底部导航栏。在主活动中,导航栏出现,但不在模拟器中。下面是MainActivity和ActivityMain文件。谢谢你的帮助

MainActivity.kt

package com.example.androidapp
    
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.navigation.NavController
import androidx.navigation.Navigation
import androidx.navigation.findNavController
import androidx.navigation.ui.AppBarConfiguration
import androidx.navigation.ui.setupActionBarWithNavController
import androidx.navigation.ui.setupWithNavController
import kotlinx.android.synthetic.main.activity_main.*
    
class MainActivity : AppCompatActivity() {
        
      private lateinit var navController: NavController
    
      override fun onCreate(savedInstanceState: Bundle?) {
            super.onCreate(savedInstanceState)
            setContentView(R.layout.activity_main)
    
            navController = findNavController(R.id.navHostFragment)
            val appBarConfiguration = AppBarConfiguration(
                 setOf(
                     R.id.photoFragment,
                     R.id.recyclerViewFragment,
                     R.id.settingsFragment
                 )
             )
    
             bottomNavigationView.setupWithNavController(navController)
             setupActionBarWithNavController(navController, appBarConfiguration)
    
        }
    
        override fun onSupportNavigateUp(): Boolean {
             return navController.navigateUp() || super.onSupportNavigateUp()
        }
        
}
活动主

<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/lightGray"
    tools:context=".MainActivity">

<fragment
    android:id="@+id/navHostFragment"
    android:name="androidx.navigation.fragment.NavHostFragment"
    android:layout_width="0dp"
    android:layout_height="0dp"
    app:defaultNavHost="true"
    app:layout_constraintBottom_toTopOf="@+id/bottomNavigationView"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:navGraph="@navigation/navigation_bottom" />

<com.google.android.material.bottomnavigation.BottomNavigationView
    android:id="@+id/bottomNavigationView"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.5"
    app:layout_constraintStart_toStartOf="parent"
    app:menu="@menu/bottom_nav_menu"/>


请您也添加您的
activity\u main.xml
文件好吗?@MohammadZarei我刚刚添加了它发现了错误!类MainActivity:AppCompatActivity()是2倍。现在它可以工作了,但当我点击RecyclerView选项卡时,应用程序正在关闭:(@oana尝试在应用程序关闭时获取日志详细信息