Multiple exceptions: Unable to start activity, Unable to instantiate fragment, Error inflating class

user_6023062 0
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I'm brand new to Kotlin and I'm following a tutorial. Running my app causes it to crash on runtime. I have three fragments, and one main activity, in a bottom navigation bar app. My goal is really just to run the app successfully so I can try out Room databases, data binding and such concepts. I searched for possible reasons why it doesn't work with me but no luck. This is the current full error message:

    2021-02-27 14:58:23.967 23883-23883/com.jwanhsulaiman.talktag E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.jwanhsulaiman.talktag, PID: 23883
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.jwanhsulaiman.talktag/com.jwanhsulaiman.talktag.MainActivity}: android.view.InflateException: Binary XML file line #21: Binary XML file line #21: Error inflating class androidx.fragment.app.FragmentContainerView
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2919)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3054)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1814)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:280)
        at android.app.ActivityThread.main(ActivityThread.java:6706)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
     Caused by: android.view.InflateException: Binary XML file line #21: Binary XML file line #21: Error inflating class androidx.fragment.app.FragmentContainerView
     Caused by: android.view.InflateException: Binary XML file line #21: Error inflating class androidx.fragment.app.FragmentContainerView
     Caused by: androidx.fragment.app.Fragment$InstantiationException: Unable to instantiate fragment com.jwanhsulaiman.talktag.ui.home.HomeFragment: could not find Fragment constructor
        at androidx.fragment.app.Fragment.instantiate(Fragment.java:625)
        at androidx.fragment.app.FragmentContainer.instantiate(FragmentContainer.java:57)
        at androidx.fragment.app.FragmentManager$3.instantiate(FragmentManager.java:483)
        at androidx.navigation.fragment.FragmentNavigator.instantiateFragment(FragmentNavigator.java:132)
        at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.java:162)
        at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.java:58)
        at androidx.navigation.NavGraphNavigator.navigate(NavGraphNavigator.java:71)
        at androidx.navigation.NavGraphNavigator.navigate(NavGraphNavigator.java:28)
        at androidx.navigation.NavController.navigate(NavController.java:1059)
        at androidx.navigation.NavController.onGraphCreated(NavController.java:639)
        at androidx.navigation.NavController.setGraph(NavController.java:592)
        at androidx.navigation.NavController.setGraph(NavController.java:557)
        at androidx.navigation.NavController.setGraph(NavController.java:539)
        at androidx.navigation.fragment.NavHostFragment.onCreate(NavHostFragment.java:248)
        at androidx.fragment.app.Fragment.performCreate(Fragment.java:2936)
        at androidx.fragment.app.FragmentStateManager.create(FragmentStateManager.java:472)
        at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:278)
        at androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:2177)
        at androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:2094)
        at androidx.fragment.app.FragmentManager.execSingleAction(FragmentManager.java:1959)
        at androidx.fragment.app.BackStackRecord.commitNowAllowingStateLoss(BackStackRecord.java:311)
        at androidx.fragment.app.FragmentContainerView.<init>(FragmentContainerView.java:176)
        at androidx.fragment.app.FragmentLayoutInflaterFactory.onCreateView(FragmentLayoutInflaterFactory.java:52)
        at androidx.fragment.app.FragmentController.onCreateView(FragmentController.java:135)
        at androidx.fragment.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:313)
        at androidx.fragment.app.FragmentActivity.onCreateView(FragmentActivity.java:292)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:780)
2021-02-27 14:58:23.971 23883-23883/com.jwanhsulaiman.talktag E/AndroidRuntime:     at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:730)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:863)
        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:824)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:515)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:423)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:374)
        at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:696)
        at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:170)
        at com.jwanhsulaiman.talktag.MainActivity.onCreate(MainActivity.kt:15)
        at android.app.Activity.performCreate(Activity.java:7136)
        at android.app.Activity.performCreate(Activity.java:7127)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1272)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2899)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3054)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1814)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:280)
        at android.app.ActivityThread.main(ActivityThread.java:6706)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
     Caused by: java.lang.NoSuchMethodException: <init> []
        at java.lang.Class.getConstructor0(Class.java:2327)
        at java.lang.Class.getConstructor(Class.java:1725)
        at androidx.fragment.app.Fragment.instantiate(Fragment.java:610)
            ... 50 more

I've tried changing the XML file on line 21 (as per the error) from fragment to androidx.fragment.app.FragmentContainerView (as per Android Studio's suggestion upon hovering with mouse. I've tried adding dependencies but nothing seems to change to the better. I'll provide how my code looks like.

MainActivity.kt (errors says it crashes on setContentView(R.layout.activity_main))

package com.jwanhsulaiman.talktag

import android.os.Bundle
import com.google.android.material.bottomnavigation.BottomNavigationView
import androidx.appcompat.app.AppCompatActivity
import androidx.navigation.findNavController
import androidx.navigation.ui.AppBarConfiguration
import androidx.navigation.ui.setupActionBarWithNavController
import androidx.navigation.ui.setupWithNavController

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        val navView: BottomNavigationView = 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.
        val appBarConfiguration = AppBarConfiguration(setOf(
                R.id.navigation_home, R.id.navigation_dashboard, R.id.navigation_notifications))
        setupActionBarWithNavController(navController, appBarConfiguration)
        navView.setupWithNavController(navController)
    }
}

activity_main.xml

<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
<androidx.constraintlayout.widget.ConstraintLayout
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingTop="?attr/actionBarSize">

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/nav_view"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="0dp"
        android:layout_marginEnd="0dp"
        android:background="?android:attr/windowBackground"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:menu="@menu/bottom_nav_menu" />

    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/nav_host_fragment"
        class = "androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:defaultNavHost="true"
        app:layout_constraintBottom_toTopOf="@id/nav_view"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:navGraph="@navigation/mobile_navigation" />

</androidx.constraintlayout.widget.ConstraintLayout>
</layout>

And the full snippet of HomeFragment in case it's related

    package com.jwanhsulaiman.talktag.ui.home

import android.content.Context
import android.os.Bundle
import android.util.Log
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.databinding.DataBindingUtil
import androidx.fragment.app.Fragment
import androidx.lifecycle.Observer
import androidx.lifecycle.ViewModelProvider
import com.jwanhsulaiman.talktag.R
import com.jwanhsulaiman.talktag.database.VocabData
import com.jwanhsulaiman.talktag.database.VocabRepository
import com.jwanhsulaiman.talktag.databinding.FragmentHomeBinding

class HomeFragment(val applicationContext: Context) : Fragment() {

    private lateinit var homeViewModel: HomeViewModel
    private lateinit var binding: FragmentHomeBinding

    override fun onCreateView(
            inflater: LayoutInflater,
            container: ViewGroup?,
            savedInstanceState: Bundle?
    ): View? {
        homeViewModel =
                ViewModelProvider(this).get(HomeViewModel::class.java)
        val root = inflater.inflate(R.layout.fragment_home, container, false)
        val textView: TextView = root.findViewById(R.id.text_home)
        homeViewModel.text.observe(viewLifecycleOwner, Observer {
            textView.text = it
        })

        binding = DataBindingUtil.inflate(inflater, R.layout.fragment_home, container, false)
        val dao = VocabData.getInstance(this).VocabDao
        val repository = VocabRepository(dao)
        val factory = HomeViewModelFactory(repository)
        homeViewModel = ViewModelProvider(this, factory).get(HomeViewModel::class.java)
        binding.myViewModel = homeViewModel
        binding.lifecycleOwner = this
        displayVocabList()

        return binding.root
    }

    private fun displayVocabList() {
    homeViewModel.vocabs.observe(viewLifecycleOwner, Observer {
        Log.i("MYTAG", it.toString())
    })

    }
}

Thanks for any insights!

android-fragments kotlin android-studio crash android
1 Answers
Caused by: java.lang.NoSuchMethodException: <init> []

Remove the constructor from HomeFragment, for two reasons:

  1. It will not work, as the fragment system requires a public zero-argument constructor

  2. You do not need to pass in a Context, as once your fragment is attached to an activity, you can call requireContext() to retrieve a Context to use (and can reference applicationContext on it if you really do need the Application)

user_1151450
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