~ does not have a NavController set

 

많은 자료들이

supportFragmentManager.findFragmentById()를 이용해서 직접 찾아주고 as 로 캐스팅하여 문제를 해결한다.

그러지 않아도 간단하게 해결할 수 있다.

 

 

MainActivity.kt

package made.by.hevton.love

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.navigation.NavController
import androidx.navigation.findNavController
import androidx.navigation.fragment.NavHostFragment
import androidx.navigation.fragment.findNavController
import made.by.hevton.love.databinding.ActivityMainBinding

class MainActivity : AppCompatActivity() {

    val binding by lazy { ActivityMainBinding.inflate(layoutInflater) }

    lateinit var navController: NavController

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)


        setContentView(binding.root);

//        잘못된 예
//        navController = binding.navHostFragment.findNavController()
        
        navController = binding.navHostFragment.getFragment<NavHostFragment>().navController


    }
}

나는 이렇게 사용한다

 

 

 

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<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"
    tools:context=".MainActivity">


    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/nav_host_fragment"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"

        app:defaultNavHost="true"
        app:navGraph="@navigation/nav_graph" />

</androidx.constraintlayout.widget.ConstraintLayout>

 

 

내일은 Navigation Jetpack 정리 강의글을 올릴 예정이다