Color property in Android
                            
                         
                        
                     
                 
                
                      Hi All,
 
 I suppose we can set the color property by two types in android application  that is:
 
    android:background="@color/yellow"
  android:background="#808080ff"
 
 My problem is that, when I am trying to set background color by "@color/yellow", it shows System.NullReferenceException: Object reference not set to an instance of an object. And if I am using "#808080ff" it works fine.
 Any-body tell me what is the problem with android:background="@color/yellow" type.....?