Error inflating class

I’m getting the following error:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.pstiming.mc/com.pstiming.mc.MainActivity}: android.view.InflateException: Binary XML file line #10 in com.pstiming.mc:layout/activity_main: Binary XML file line #10 in com.pstiming.mc:layout/activity_main: Error inflating class androidx.fragment.app.FragmentContainerView

however activity_main.xml is

<?xml version="1.0" encoding="utf-8"?>

<androidx.fragment.app.FragmentContainerView
xmlns:android=“http://schemas.android.com/apk/res/android
xmlns:tools=“http://schemas.android.com/tools
android:id=“@+id/fragment_container”
android:name=“com.pstiming.mc.WaterPoloFragment”
android:layout_width=“match_parent”
android:layout_height=“match_parent”
tools:context=“.MainActivity” />

which is copied from the book with the exception of the changed name. Line 10 is the tools:context line which is the same as the book. MainActivity.kt is the same as the book.

Can you share the Kotlin and XML code for WaterPoloFragment? There might be a bug in one of those files.

When I try to post the XML for the WaterPoloFragment, I get the following error:

An error occurred: Sorry, new users can only put 2 links in a post.

package com.pstiming.mc

// WaterPoloFragment.kt
import androidx.lifecycle.ViewModelProvider
import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import com.pstiming.mc.databinding.FragmentWaterPoloBinding

class WaterPoloFragment : Fragment() {

private lateinit var binding : FragmentWaterPoloBinding

companion object {
    fun newInstance() = WaterPoloFragment()
}

private lateinit var viewModel: WaterPoloViewModel

override fun onCreateView( inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle? ): View? {
    binding = FragmentWaterPoloBinding.inflate(inflater, container, false)
    return binding.root
}

override fun onViewCreated( view: View, savedInstanceState: Bundle? ) {
    super.onViewCreated(view, savedInstanceState)

// binding.ivAwayIncScore.setOnClickListener {
// binding.tvAwayScore.text = (binding.tvAwayScore.text.toString().toInt() + 1).toString()
// }

}

}

Use the </> button when typing up your message. That will wrap your XML code in styling specific for big chunks of code.

For example:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_margin="16dp">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textAppearance="?attr/textAppearanceHeadline5"
        android:text="@string/crime_title_label" />
    <EditText
        android:id="@+id/crime_title"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="@string/crime_title_hint"
        android:importantForAutofill="no"
        android:inputType="text" />
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textAppearance="?attr/textAppearanceHeadline5"
        android:text="@string/crime_details_label" />
    <Button
        android:id="@+id/crime_date"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        tools:text="Wed May 11 11:56 EST 2022" />
    <CheckBox
        android:id="@+id/crime_solved"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/crime_solved_label" />
</LinearLayout>
<?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=".WaterPoloFragment"
        android:id="@+id/contraint_layout_wp">

    <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/away_label"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintTop_toTopOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>

That all looks fine to me. Any chance you could post the full stacktrace for the crash? There might be a line with a “Caused by:” message that could really help us narrow down the issue.

FATAL EXCEPTION: main
Process: com.pstiming.mc, PID: 23833
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.pstiming.mc/com.pstiming.mc.MainActivity}: android.view.InflateException: Binary XML file line #10 in com.pstiming.mc:layout/activity_main: Binary XML file line #10 in com.pstiming.mc:layout/activity_main: Error inflating class androidx.fragment.app.FragmentContainerView
	at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3685)
	at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3842)
	at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:103)
	at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
	at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2252)
	at android.os.Handler.dispatchMessage(Handler.java:106)
	at android.os.Looper.loopOnce(Looper.java:201)
	at android.os.Looper.loop(Looper.java:288)
	at android.app.ActivityThread.main(ActivityThread.java:7842)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
Caused by: android.view.InflateException: Binary XML file line #10 in com.pstiming.mc:layout/activity_main: Binary XML file line #10 in com.pstiming.mc:layout/activity_main: Error inflating class androidx.fragment.app.FragmentContainerView
Caused by: android.view.InflateException: Binary XML file line #10 in com.pstiming.mc:layout/activity_main: Error inflating class androidx.fragment.app.FragmentContainerView
Caused by: java.lang.reflect.InvocationTargetException
	at java.lang.reflect.Constructor.newInstance0(Native Method)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:343)
	at android.view.LayoutInflater.createView(LayoutInflater.java:858)
	at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:1010)
	at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:965)
	at android.view.LayoutInflater.inflate(LayoutInflater.java:663)
	at android.view.LayoutInflater.inflate(LayoutInflater.java:538)
	at android.view.LayoutInflater.inflate(LayoutInflater.java:485)
	at com.android.internal.policy.PhoneWindow.setContentView(PhoneWindow.java:461)
	at android.app.Activity.setContentView(Activity.java:3523)
	at androidx.activity.ComponentActivity.setContentView(ComponentActivity.java:465)
	at com.pstiming.mc.MainActivity.onCreate(MainActivity.kt:41)
	at android.app.Activity.performCreate(Activity.java:8054)
	at android.app.Activity.performCreate(Activity.java:8034)
	at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1341)
	at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3666)
	at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3842)
	at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:103)
	at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
	at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2252)
	at android.os.Handler.dispatchMessage(Handler.java:106)
	at android.os.Looper.loopOnce(Looper.java:201)
	at android.os.Looper.loop(Looper.java:288)
	at android.app.ActivityThread.main(ActivityThread.java:7842)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
Caused by: java.lang.UnsupportedOperationException: FragmentContainerView must be within a FragmentActivity to use android:name="com.pstiming.mc.WaterPoloFragment"
	at androidx.fragment.app.FragmentContainerView.<init>(FragmentContainerView.kt:120)

Ah, here’s the error. What class does your MainActivity extend? In the book we always use AppCompatActivity.

It looks like you might be facing an issue with the XML attributes. Double-check the XML file for any unusual characters or discrepancies in attribute names. In your posted XML snippet, it seems there might be an issue with the double quotes around attributes. Try replacing the curly double quotes (“ ”) with straight double quotes (" ") and see if that resolves the problem. Ensure consistency in attribute naming and spacing. If the issue persists, share more details or the related code for further assistance.