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Fragment View's state is broken by FragmentManager

I wanted to retain views through fragment replace operation and noticed a strange bug:
After fragment's View is destroyed through replace operation, it still has a parent, however, the parent doesn't have the view among its children.
private View view;
#Override
public View onCreateView(...) {
if (view == null) {
view = // ... inflate view
} else {
// at this point, view has mParent, but can't be removed
// because the parent does not have it among its children
}
return view;
}
#Override
public void onDestroyView() {
// I could remove the view from its parent here manually,
// however, it will cause fragment's content to disappear before
// the replace animation ends
}
Notice how the view has a reference to its parent through mParent, but the parent has zero mChildrenCount.
This causes fragment transaction to crash with an exception when trying to reuse the view:
java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first. I find this behavior to be exceptionally wrong since it leaves the fragment's view in an unusable state.
If someone has faced this issue, please share your workarounds. I have come up with a temporary dirty reflective solution:
#Override
public View onCreateView(...) {
if (view == null) {
view = // ... inflate view
} else {
// clear parent reference (because SDK fails to do it)
Field f = View.class.getDeclaredField("mParent");
f.setAccessible(true);
f.set(view, null);
}
return view;
}

The specified child already has a parent. You must call removeView() on the child's parent first (Android)

I have to switch between two layouts frequently. The error is happening in the layout posted below.
When my layout is called the first time, there doesn't occur any error and everything's fine. When I then call a different layout (a blank one) and afterwards call my layout a second time, it throws the following error:
> FATAL EXCEPTION: main
> java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
My layout-code looks like this:
tv = new TextView(getApplicationContext()); // are initialized somewhere else
et = new EditText(getApplicationContext()); // in the code
private void ConsoleWindow(){
runOnUiThread(new Runnable(){
#Override
public void run(){
// MY LAYOUT:
setContentView(R.layout.activity_console);
// LINEAR LAYOUT
LinearLayout layout=new LinearLayout(getApplicationContext());
layout.setOrientation(LinearLayout.VERTICAL);
setContentView(layout);
// TEXTVIEW
layout.addView(tv); // <========== ERROR IN THIS LINE DURING 2ND RUN
// EDITTEXT
et.setHint("Enter Command");
layout.addView(et);
}
}
}
I know this question has been asked before, but it didn't help in my case.

The error message says what You should do.
// TEXTVIEW
if(tv.getParent() != null) {
((ViewGroup)tv.getParent()).removeView(tv); // <- fix
}
layout.addView(tv); // <========== ERROR IN THIS LINE DURING 2ND RUN
// EDITTEXT

simply pass the argument
attachtoroot = false
View view = inflater.inflate(R.layout.child_layout_to_merge, parent_layout, false);

I came here on searching the error with my recyclerview but the solution didn't work (obviously). I have written the cause and the solution for it in case of recyclerview. Hope it helps someone.
The error is caused if in the onCreateViewHolder() the following method is followed:
layoutInflater = LayoutInflater.from(context);
return new VH(layoutInflater.inflate(R.layout.single_row, parent));
Instead it should be
return new VH(layoutInflater.inflate(R.layout.single_row, null));

I got this message while trying to commit a fragment using attach to root to true instead of false, like so:
return inflater.inflate(R.layout.fragment_profile, container, true)
After doing:
return inflater.inflate(R.layout.fragment_profile, container, false)
It worked.

You must first remove the child view from its parent.
If your project is in Kotlin, your solution will look slightly different than Java. Kotlin simplifies casting with as?, returning null if left side is null or cast fails.
(childView.parent as? ViewGroup)?.removeView(childView)
newParent.addView(childView)
Kotlin Extension Solution
If you need to do this more than once, add this extension to make your code more readable.
childView.removeSelf()
fun View?.removeSelf() {
this ?: return
val parentView = parent as? ViewGroup ?: return
parentView.removeView(this)
}
It will safely do nothing if this View is null, parent view is null, or parent view is not a ViewGroup

frameLayout.addView(bannerAdView); <----- if you get error on this line the do like below..
if (bannerAdView.getParent() != null)
((ViewGroup) bannerAdView.getParent()).removeView(bannerAdView);
frameLayout.addView(bannerAdView); <------ now added view

If other solution is not working like:
View view = inflater.inflate(R.layout.child_layout_to_merge, parent_layout, false);
check for what are you returning from onCreateView of fragment is it single view or viewgroup? in my case I had viewpager on root of xml of fragment and I was returning viewpager, when i added viewgroup in layout i didnt updated that i have to return viewgroup now, not viewpager(view).

My error was define the view like this:
view = inflater.inflate(R.layout.qr_fragment, container);
It was missing:
view = inflater.inflate(R.layout.qr_fragment, container, false);

In my case it happens when i want add view by parent to other view
View root = inflater.inflate(R.layout.single, null);
LinearLayout lyt = root.findViewById(R.id.lytRoot);
lytAll.addView(lyt); // -> crash
you must add parent view like this
View root = inflater.inflate(R.layout.single, null);
LinearLayout lyt = root.findViewById(R.id.lytRoot);
lytAll.addView(root);

Simplified in KOTLIN
viewToRemove?.apply {
if (parent != null) {
(parent as ViewGroup).removeView(this)
}
}

In my case, I had id named as "root" for constraint layout, which was conflicting the existing parent root id.
Try to change the id.
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/root" //<--It should not named as root.
android:layout_width="match_parent"
android:layout_height="match_parent"
</androidx.constraintlayout.widget.ConstraintLayout>

In my case the problem was caused by the fact that I was inflating parent View with <merge> layout. In this case, addView() caused the crash.
View to_add = inflater.inflate(R.layout.child_layout_to_merge, parent_layout, true);
// parent_layout.addView(to_add); // THIS CAUSED THE CRASH
Removing addView() helped to solve the problem.

The code below solved it for me:
#Override
public void onDestroyView() {
if (getView() != null) {
ViewGroup parent = (ViewGroup) getView().getParent();
parent.removeAllViews();
}
super.onDestroyView();
}
Note: The error was from my fragment class and by overriding the onDestroy method like this, I could solve it.

My problem is related to many of the other answers, but a little bit different reason for needing to make the change... I was trying to convert an Activity to a Fragment. So I moved the inflate code from onCreate to onCreateView, but I forgot to convert from setContentView to the inflate method, and the same IllegalStateException brought me to this page.
I changed this:
binding = DataBindingUtil.setContentView(requireActivity(), R.layout.my_fragment)
to this:
binding = DataBindingUtil.inflate(inflater, R.layout.my_fragment, container, false)
That solved the problem.

You just need to pass attachToRoot parameter false.
mBinding = FragmentCategoryBinding.inflate(inflater, container, false)

If you're using ViewBinding, make sure you're referring to the right binding!
I had this issue when I was trying to inflate a custom dialog from within an activity:
AlertDialog.Builder builder = new AlertDialog.Builder(this);
final AlertBinding alertBinding = AlertBinding.inflate(LayoutInflater.from(this), null, false);
builder.setView(binding.getRoot()); // <--- I was using binding (which is my Activity's binding), instead of alertBinding.

This is how I do my custom dialog
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
android.view.View views = getLayoutInflater().inflate(layout_file, null, false);
builder.setView(views);
dialog = builder.create();
dialog.show();
I changed it into this and its works for me, I hope this helps
Dialog dialog = new Dialog(MainActivity.this);
dialog.setContentView(layout_file);
dialog.show();

check if you already added the view
if (textView.getParent() == null)
layout.addView(textView);

if(tv!= null){
((ViewGroup)tv.getParent()).removeView(tv); // <- fix
}

I was facing the same error, and look what I was doing. My bad, I was trying to add the same view NativeAdView to the multiple FrameLayouts, resolved by creating a separate view NativeAdView for each FrameLayout, Thanks

In my case I was accidentally returning a child view from within Layout.onCreateView() as shown below:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v= inflater.inflate(R.layout.activity_deliveries, container, false);
RecyclerView rv = (RecyclerView) v.findViewById(R.id.deliver_list);
return rv; // <- here's the issue
}
The solution was to return the parent view (v) instead of the child view (rv).

I found another fix:
if (mView.getParent() == null) {
myDialog = new Dialog(MainActivity.this);
myDialog.setContentView(mView);
createAlgorithmDialog();
} else {
createAlgorithmDialog();
}
Here i just have an if statement check if the view had a parent and if it didn't Create the new dialog, set the contentView and show the dialog in my "createAlgorithmDialog()" method.
This also sets the positive and negative buttons (ok and cancel buttons) up with onClickListeners.

In my case, I had an adapter which worked with a recyclerView, the items that were being passed to the adapter were items with their own views.
What was required was just a LinearLayout to act as a container for every item passed, so what I was doing was to grab the item in the specified position inside onBindViewHolder then add it to the LinearLayout, which was then displayed.
Checking the basics in docs,
When an item scrolls off the screen, RecyclerView doesn't destroy its
view
Therefore, with my items, when I scroll towards a direction, then change towards the opposite direction - fast, the racently displayed items have not been destroyed, meaning, the items are still associated with the LinearLayout container, then on my end, I'm trying to attach to another container, which ends up with a child having a parent already.
My solution was to check if the specified item has a parent, if it has, I assign it to a variable, then call parentVar.removeView(item), then assign the new parent.
Here's the sample code(Problematic Adapter):
override fun onBindViewHolder(holder: QuestionWidgetViewHolder, position: Int) {
holder.linearLayoutContainer.removeAllViewsInLayout()
val questionWidget: QuestionWidget =
dataSource[position]
questionWidget.setValueChangedListener(this)
holder.linearLayoutContainer.addView(questionWidget)/*addView throws error once in a while*/
}
inner class QuestionWidgetViewHolder(mView: View) :
RecyclerView.ViewHolder(mView) {
val linearLayoutContainer: LinearLayout =
mView.findViewById(R.id.custom_question_widget_container)
}
Content of the R.id.custom_question_widget_container:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/custom_question_widget_container"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:orientation="vertical"
android:padding="10dp" />
So, the questionWidget seems to have been retaining the parent for almost 4 steps outside visibility, and when I scroll to the opposite direction fast, I would encounter it still with its parent, then I'm attempting to add it to another container.
Here's the fix - option 1:
override fun onBindViewHolder(holder: QuestionWidgetViewHolder, position: Int) {
holder.linearLayoutContainer.removeAllViewsInLayout()
val questionWidget: QuestionWidget =
dataSource[position]
questionWidget.setValueChangedListener(this)
val initialWidgetParent : ViewParent? = questionWidget.parent
//attempt to detach from previous parent if it actually has one
(initialWidgetParent as? ViewGroup)?.removeView(questionWidget)
holder.linearLayoutContainer.addView(questionWidget)
}
Another better solution - option 2:
override fun onBindViewHolder(holder: QuestionWidgetViewHolder, position: Int) {
holder.linearLayoutContainer.removeAllViewsInLayout()
val questionWidget: QuestionWidget =
dataSource[position]
questionWidget.setValueChangedListener(this)
val initialWidgetParent : ViewParent? = questionWidget.parent
//if it's in a parent container already, just ignore adding it to a view, it's already visible
if(initialWidgetParent == null) {
holder.linearLayoutContainer.addView(questionWidget)
}
}
Actually, it's much of asking the child if it has a parent before adding it to a parent.

I tried all the things that you guys suggested, with no luck.
But, I managed to fix it by moving all my binding initializations from onCreate to onCreateView.
onCreate(){
binding = ScreenTicketsBinding.inflate(layoutInflater)
}
MOVE TO
onCreateView(...){
binding = ScreenTicketsBinding.inflate(layoutInflater)
}

You can use this methode to check if a view has children or not .
public static boolean hasChildren(ViewGroup viewGroup) {
return viewGroup.getChildCount() > 0;
}

My case was different the child view already had a parent view i am adding the child view inside parent view to different parent. example code below
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="#dimen/lineGap"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#color/black1"
android:layout_gravity="center"
android:gravity="center"
/>
</LinearLayout>
And i was inflating this view and adding to another LinearLayout, then i removed the LinaarLayout from the above layout and its started working
below code fixed the issue:
<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:textColor="#color/black1" />

It happened with me when I was using Databinding for Activity and Fragments.
For fragment - in onCreateView we can inflate the layout in traditional way using inflater.
and in onViewCreated method, binding object can be updated as
binding = DataBindingUtil.getBinding<FragmentReceiverBinding>(view) as FragmentReceiverBinding
It solved my issue

In my case, I was doing this (wrong):
...
TextView content = new TextView(context);
for (Quote quote : favQuotes) {
content.setText(quote.content);
...
instead of (good):
...
for (Quote quote : favQuotes) {
TextView content = new TextView(context);
content.setText(quote.content);
...

If you are working with MaterialAlertDialog, this worked for me:
(yourChildView.parent as? ViewGroup)?.removeView(yourChildView)

If in your XML you have layout with id "root" It`s problem, just change id name

How did I stop IllegalStateExceptions from being thrown with LayoutInflater().inflate(int resource, ViewGroup root, boolean attachToRoot)?

I recently recently ran into an issue while setting up a viewpager with 3 fragments. When the application ran it crashed with a
java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first
Here is the code for creating list list of fragments to pass to the pageAdapter.
private Vector<Fragment> getFragments() {
Vector<Fragment> list = new Vector<Fragment>();
list.add(new Fragment1());
list.add(new Fragment2());
list.add(new Fragment3());
return list;
Each of the fragments were essentially the same except for a being created with different layouts. Here was the original code I had for one of the fragments.
public class Fragment1 extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = getActivity().getLayoutInflater().inflate(R.layout.fragment1, container);
return v;
}
}
But when I ran it like this it kept crashing with the IllegalStateException. I found that the issue was coming from the fragments being created. After some Googling I tried changing the code for the fragment to this.
public class Fragment1 extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = getActivity().getLayoutInflater().inflate(R.layout.fragment1, container, false);
return v;
}
}
This resolved the issue and I no longer got the IllegalStateException except I have no idea how this worked. What exactly does this boolean do? And what does this exception mean? I had tried adding the method call like it suggusted but that did not resolve it. Also I tried changing this boolean to true and I got the same error again. The android docs say its attachToRoot but isn't that what I want to do? Attach my 3 fragments to the rootview, which is the viewpager? If anyone could explain this it would be greatly appreciated.

The boolean parameter of the 3-arg version of LayoutInflater.inflate() determines whether the LayoutInflater will add the inflated view to the specified container. For fragments, you should specify false because the Fragment itself will add the returned View to the container. If you pass true or use the 2-arg method, the LayoutInflater will add the view to the container, then the Fragment will try to do so again later, which results in the IllegalStateException.

Set id and get id of inflated view?

I have to inflate the group of items in a listview and i need to find inflated view anywhere in the program .
May I know how to find the view.
How to set id and get id of inflated listview.
Thanks in Advance

In the Adapter of your list view
public View getView(int position, View convertView, ViewGroup parent) {
View vi = convertView;
if (convertView == null)
vi = inflater.inflate(R.layout.newlistrow, null);
//Access your inflated layout using vi
TextView sometextview= (TextView) vi.findViewById(R.id.textview); // sometextview

Typically you don't find views in a list view. The adapter behind the list view will pass you the view plus the underlying position of your data that you need to render via the getView method.
To answer your question of how to get or set id of inflated view you should call getId or setId on the inflated view.
http://developer.android.com/reference/android/view/View.html#setId(int)
http://developer.android.com/reference/android/view/View.html#getId()
View myView = LayoutInflater.from(activity).inflate(R.layout.list_item_punch_log, null);
myView.setId(android.R.id.button1);
int id = myView.getId();
However doing this and finding views in a list view is a very dangerous act as it will cause some really funny behaviors on the listview. Maybe you can tell us what you are trying to do and we can guide you from there.

What is "convertView" parameter in ArrayAdapter getView() method

Can someone tell me what the convertView parameter is used for in the getView() method of the Adapter class?
Here is a sample code take from here:
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
if (v == null) {
LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.row, null);
}
Order o = items.get(position);
if (o != null) {
TextView tt = (TextView) v.findViewById(R.id.toptext);
TextView bt = (TextView) v.findViewById(R.id.bottomtext);
if (tt != null) {
tt.setText("Name: "+o.getOrderName()); }
if(bt != null){
bt.setText("Status: "+ o.getOrderStatus());
}
}
return v;
}
What should we pass via convertView?
What I've found, take from here:
Get a View that displays the data at the specified position in the
data set. You can either create a View manually or inflate it from an
XML layout file. When the View is inflated, the parent View (GridView,
ListView...) will apply default layout parameters unless you use
inflate(int, android.view.ViewGroup, boolean) to specify a root view
and to prevent attachment to the root.
Parameters
position -- The position of the item within the adapter's data set of the item whose view we want.
convertView -- The old view to reuse, if possible. Note: You should check that this view is non-null and of an appropriate type before
using. If it is not possible to convert this view to display the
correct data, this method can create a new view.
parent -- The parent that this view will eventually be attached to Returns
returns -- A View corresponding to the data at the specified position.

You shouldn't be calling that method by yourself.
Android's ListView uses an Adapter to fill itself with Views. When the ListView is shown, it starts calling getView() to populate itself. When the user scrolls a new view should be created, so for performance the ListView sends the Adapter an old view that it's not used any more in the convertView param.