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

android

view-management

android-development

best-practices

byAlex Kataev·Nov 6, 2024

You've stumbled upon the unexpected-- The specified child already has a parent error. Don't panic; it's fixable!

if (child.getParent() != null) {
    ((ViewGroup)child.getParent()).removeView(child); // Let's break the shackles here!
}
yourNewParent.addView(child); // Voila! New home for our kid.

The error decoded

This section will take you through some common scenarios that often lead to our notorious 'child has a parent' error. Time to decode!

Juggling dynamically with views

One aspect of Android development is dynamically adding or removing views. Be wary, this could be an invitation to our unwelcome error. To safely play:

Ensure the view is an orphan (has no parent) before adding it elsewhere.
Inflate views with care, inflate(..., false) will prevent surprise adoptive parents.
Get rid of outgrown views prudently to avoid any family feud.

Moving layouts—Have you packed everything?

Switching layouts may turn tricky sometimes, so:

Say goodbye to previous parent with removeView().
And only then, introduce your view to the new parent layout.

Beware of false attachment while inflating

In inflate(), setting attachToRoot to false is key. Failure to abide may:

Get the view attached to the root like a magnet.
Lead to our error when you try to add the same view elsewhere.

Kotlin's magic trick

Kotlin developers can do this neat trick to clean up their code for removing views:

fun View.removeSelf() {
    (parent as? ViewGroup)?.removeView(this)
}

Just call childView.removeSelf(), the magic word!

Keeping it smooth while parent-switching views

To make your UI changes smooth and less prone to errors, follow these best practices, and thank me later ;-)

Parental check before custody transfer

Before moving a view to another parent, check if it's still stuck with its previous parent:

if(view.getParent() != null) {
    ((ViewGroup) view.getParent()).removeView(view);
}

It's as effective as checking for monsters under the bed every night!

Remember the view family tree

Android view hierarchy is a robust family tree you should understand:

Each view can only be a golden child with one parent.
If you're thinking of giving your view to another parent, it'll automatically cut ties with its previous one.