Error parsing XML: unbound prefix, Most relevant problems in android

During creating different layout in android using xml, may be sometimes miss small things, that is necessary to create layouts.

Xml Layout File:

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout

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

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    tools:context=".MainActivity" >

    <TextView

        android:text="Top Title"

        android:id="@+id/TextView"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:layout_alignParentTop="true">

    </TextView>

</RelativeLayout>

In eclipse you should looks like this error:

How to solve this problems. lets talk some tips:

 Most important this aspect you forget to put, this :

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

you just put this on main or first node of xml layout;

Like this

<?xml version="1.0" encoding="utf-8"?>

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

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

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    tools:context=".MainActivity" >

    <TextView

        android:text="Top Title"

        android:id="@+id/TextView"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:layout_alignParentTop="true">

    </TextView>

</RelativeLayout>

I think, now your problem solve.

Please dontt forget this problem on google.

Have a fun with solved problem and Happy Coding!!!