The specified child already has a parent. You must

问题:

In my app, 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 isn't occurring 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 gives me 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.

回答1:

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

回答2:

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));

回答3:

simply pass the attachtoroot argument as false

View view = inflater.inflate(R.layout.child_layout_to_merge, parent_layout, false);

回答4:

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.

回答5:

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).

回答6:

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.

回答7:

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.

回答8:

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.

回答9:

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

回答10:

You can use this methode to check if a view has children or not .

public static boolean hasChildren(ViewGroup viewGroup) {
    return viewGroup.getChildCount() > 0;
 }

回答11:

check if you already added the view

if (textView.getParent() == null)
    layout.addView(textView);

回答12:

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