Full text is not displayed in K2 Item view.

I have this settings in item view options:
Introtex: Hide
Fulltext: Show

Settings in Item view options in category listings:
Introtext: Show
Introtext word limit: 30

Advanced:
Use one editor window for introtext & fulltext: Yes

Also i have edited file item.php at location \components\com_k2\models\
i change the following line :

if ($item->params->get('catItemIntroTextWordLimit') && $task == 'category')

with following :

if ($item->params->get('catItemIntroTextWordLimit') && ($task == 'category' || $task == 'user' || $task == 'tag' || $task == 'date' || $task == 'search' || $task == ''))


How to display the full text of the article in item view layout?

First, hacking core code is a really bad idea. I recommend to revert your modifications. If full text is not displayed in item view then this probably has to do with the category settings ( ensure that it is not inheriting from an other category ) or your template overrides.

I revert my modifications
settings are not inheriting from an other category
And nothing change in the item view layout - there is no text displayed
How to check if my template overrides?

You need to check that there only one folder ( named "default" ) under components/com_k2/templates and there are no folder/files under templates/YOUR_SITE_TEMPLATE/html/com_k2 . Finally note that since you are using a single editor, the full text variable contains the text you enter after you click the "Read more" button.