Layout attribute is not defined - Android Studio

Issue

Undeclared namespace prefix "android" (for attribute "layout_width")

How can I fix this? This says that android is not defined. How can I solve it? please help

Solution

try to add this in the layout

xmlns:android="http://schemas.android.com/apk/res/android

here is an example:

<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="wrap_content"
    android:orientation="vertical">

Answered By - Kyler Nguyen