Error inflating class fragment

If you don't want to change anything and go with "fragment" tag

do this,

<fragment
 android:visibility="gone" (Visibility will not work, just helps in removing frag from xml viewer)(If you want the visibility to be gone make it in your fragment root element visibility=gone)
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:name="com.example.YOUR_FRAGMENT" (This is important)
 />

Use androidx.fragment.app.FragmentContainerView instead of fragment. Here is a example:

 <androidx.fragment.app.FragmentContainerView 
          android:id="@+id/fragmentDetails"
          android:layout_height="fill_parent"
          android:layout_width="fill_parent"
          class="de.androidbuch.activiti.task.TaskDetailsFragment"/> 

I added an id to my fragment that's it everything works fine. Before this, I changed the manifests file as mentioned above but didn't solve my error. When you see error try to read it fully you'll get to know why there is an error. In my case, in the middle of the error trace, it was shown that the fragment id is missing.

<fragment
       android:layout_width="0dp"
       android:layout_weight="2"
       android:layout_height="match_parent"
       class="com.example.mydemofragmentapp.FoodListFragment"
       android:id="@+id/none"/>

I want to add a possible answer. So here we go.

My situation is, I change my project from Java to Kotlin, and then add Navigation Component. After migrating to Kotlin, then I add the nav_graph.xml. But, after try running the app, I got an inflating error. After checking further and comparing to other projects, turn out My nav_graph.xml did not have app:startDestination="@id/mainFragment". After adding app:startDestination, the error went away and my project runs just fine with no error.

nav_graph.xml

<?xml version="1.0" encoding="utf-8"?>
<navigation 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:id="@+id/nav_graph"
    app:startDestination="@id/mainFragment">
    <fragment
        android:id="@+id/mainFragment"
        android:name="fragment.MainFragment"
        android:label="fragment_main"
        tools:layout="@layout/fragment_main" />
</navigation>

So, don't forget the app:startDestination.

make sure that u have used this one

<meta-data
            android:name="com.google.android.maps.v2.API_KEY"
            android:value="AIzaSyBEwmfL0GaZmdVqdTxxxxxxxx-rVgvY" />

not this..

<meta-data 
         android:name="com.google.android.gms.version" 
          android:value="AIzaSyBEwmfL0GaZmdVqdTCvxxxxxxx-rVgvY" /> 

If you use obfuscation with Navigation component you need to exclude android's fragment and your args. Add these lines to your proguard-rules files:

# Exclude the fragments and argType for navigation component.
-keep class * extends androidx.fragment.app.Fragment{}
-keep class com.safetonet.presentation.features.parent.adddevice.model.PresentableAddDeviceData

I did not have the androidx.fragment:fragment dependency.

You can get the latest version from the Jetpack/ AndroidX docs:

dependencies {
    def fragment_version = "1.2.5"

    // Java language implementation
    implementation "androidx.fragment:fragment:$fragment_version"
    // Kotlin
    implementation "androidx.fragment:fragment-ktx:$fragment_version"
    // Testing Fragments in Isolation
    debugImplementation "androidx.fragment:fragment-testing:$fragment_version"
}

Make sure You have put your google-services.json on your respective folder and oviously add

<meta-dataandroid:name="com.google.android.geo.API_KEY" android:value="XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX" />

in your manifest file. Check your gradle with "implementation 'com.google.android.gms:play-services-maps:15.0.1'"

It will work.

Here is my solution to this problem.

Caused by: android.view.InflateException: Binary XML file line #31: Error inflating class fragment
Caused by: java.lang.IllegalArgumentException: Binary XML file line #31: Duplicate id 0x7f09006d, tag null, or parent id 0xffffffff with another fragment for com.example.eduardf.audit.DateTime

In my case, the error occurred when re-opening the DialogFragment with a Fragment.

<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">
        <TextView
            android:id="@+id/title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:drawableStart="@drawable/ic_black_edit_24px"
            android:singleLine="true" />
        <fragment
            android:id="@+id/fragment_date"
            android:name="com.example.eduardf.audit.DateTime"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            tools:layout="@layout/fragment_date_time" />
    </LinearLayout>
</android.support.constraint.ConstraintLayout>

DailogFragment stores the fragment after the first inflate. To prevent this from happening, I forcibly deleted the fragment.

@Override
public void onDestroyView () {
    if (!(afterRotate || getActivity() == null)) {
        final FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
        final Fragment fragment = fragmentManager.findFragmentById(R.id.fragment_date);
        if (fragment != null)
            fragmentManager.beginTransaction().remove(fragment).commit();
    }
    super.onDestroyView();
}

Also had to take care of unnecessary removal of the fragment, for example, when you rotate the screen.

private boolean afterRotate = false;
...
@Override
public void onSaveInstanceState (Bundle outState) {
    super.onSaveInstanceState(outState);
    afterRotate = true;
}

For me, refactored code caused the problem. I moved a fragment into a new package and one of the references in the xml file caused the bug. So inspect your code very well

My problem was that I am adding Google maps API key in the value folder! move it to src/debug/res/values/sensitive_keys.xml

<activity android:name=".SignUp" android:configChanges="keyboardHidden|orientation|screenSize">

Add this line to all your activities to avoid crash with orientation changes. This will avoid the activity being loaded again and again on orientation changes.

Credit: enter link description here

This is one of the errors you could get If your activity is not registered on the manifest. Check and ensure that your activity is registered on the manifest, that could be the possible cause of your error.