Android XML layout: Error parsing XML: not well-formed (invalid token) - I did close my View tags -

i getting error on button view. many questions saw on so, seems error arises when don't close views properly.

i think have closed tags still getting error. why that?

<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="${relativepackage}.${activityclass}" >      <button          android:layout_width="wrap_content"         android:layout:height="wrap_content"         android:text="@string/mainactivity_button1"         android:onclick="startsecondactivity" />  </relativelayout> 

there's additional/typo : in attribute name.

replace

android:layout:height 

with

android:layout_height 

the error not unclosed tags xml syntax problems in general. in xml, can have 1 namespace prefix attribute, , namespace prefixes separated name :.