frequent issues arising in android view, Error parsing XML: unbound prefix

Question

I have frequent problem in android view, Error parsing XML: unbound prefix on Line 2.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout android:orientation="vertical" android:id="@+id/myScrollLayout" 
android:layout_width="fill_parent"  android:layout_height="wrap_content">
    <TextView android:layout_height="wrap_content" android:layout_width="fill_parent" 
    android:text="Family" android:id="@+id/Family" 
    android:textSize="16px" android:padding="5px" 
    android:textStyle="bold" android:gravity="center_horizontal">
    </TextView>

    <ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="fill_parent" android:layout_height="wrap_content"
        android:orientation="vertical" android:scrollbars="vertical">
        <LinearLayout android:orientation="vertical" android:id="@+id/myMainLayout" 
        android:layout_width="fill_parent"  android:layout_height="wrap_content">
        </LinearLayout>
    </ScrollView>

</LinearLayout>

Answer 1

A couple of reasons that this can happen:

1) You see this error with an incorrect namespace, or a typo in the attribute. Like 'xmlns' is wrong, it should be xmlns:android

2) First node needs to contain: xmlns:android="http://schemas.android.com/apk/res/android"

3) If you are integrating AdMob, check custom parameters like ads:adSize, you need

xmlns:ads="http://schemas.android.com/apk/lib/com.google.ads"

4) If you are using LinearLayout you might have to define tools:

xmlns:tools="http://schemas.android.com/tools"