K2 installed on Joomla 2.5.
I want to set Display Options of articles in a blog list by Category.
That is, for example:

• all articles of Category A: show article title
• all articles of Category B: hide article title, show create date...

Without K2 I should set these options for each article, if different from the Default value.

After installing K2 I have imported the content from Joomla.
Now I go to operate with K2 menu.
In Edit category I try to set some options, in different sections: Category item layout, Category view options, Item view options in category listings...
But nothing changes. The default setting of Joomla (or specific setting for each article) is in effect.
Could you help me?
Thank you.

Make sure you have followed the following steps to setup correctly your categories:

1) Setup the parameters for Category A through the K2 Categories.
2) Setup the parameters for Category B through the K2 Categories.
3) On the menu item choose only the Category A to show its items. If you wish to choose more than one, only then put parameters in the menu item.

When importing articles from Joomla! the parameters are not imported as well.

Yes, this is what I do.
Now I have tried to empty all K2 tables, and import form Joomla again.

Here following the PARAMS field for Category A in table k2_categories

{"inheritFrom":"0","theme":"","num_leading_items":"2","num_leading_columns":"1","leadingImgSize":"Large","num_primary_items":"4","num_primary_columns":"2","primaryImgSize":"Medium","num_secondary_items":"4","num_secondary_columns":"1","secondaryImgSize":"Small","num_links":"4","num_links_columns":"1","linksImgSize":"XSmall","catCatalogMode":"0","catFeaturedItems":"1","catOrdering":"","catPagination":"2","catPaginationResults":"1","catTitle":"1","catTitleItemCounter":"1","catDescription":"1","catImage":"1","catFeedLink":"1","catFeedIcon":"1","subCategories":"1","subCatColumns":"2","subCatOrdering":"","subCatTitle":"1","subCatTitleItemCounter":"1","subCatDescription":"1","subCatImage":"1","itemImageXS":"","itemImageS":"","itemImageM":"","itemImageL":"","itemImageXL":"","catItemTitle":"0","catItemTitleLinked":"0","catItemFeaturedNotice":"0","catItemAuthor":"1","catItemDateCreated":"1","catItemRating":"0","catItemImage":"1","catItemIntroText":"1","catItemIntroTextWordLimit":"","catItemExtraFields":"0","catItemHits":"0","catItemCategory":"1","catItemTags":"1","catItemAttachments":"0","catItemAttachmentsCounter":"0","catItemVideo":"0","catItemVideoWidth":"","catItemVideoHeight":"","catItemAudioWidth":"","catItemAudioHeight":"","catItemVideoAutoPlay":"0","catItemImageGallery":"0","catItemDateModified":"0","catItemReadMore":"1","catItemCommentsAnchor":"1","catItemK2Plugins":"1","itemDateCreated":"0","itemTitle":"0","itemFeaturedNotice":"1","itemAuthor":"1","itemFontResizer":"1","itemPrintButton":"1","itemEmailButton":"1","itemSocialButton":"1","itemVideoAnchor":"1","itemImageGalleryAnchor":"1","itemCommentsAnchor":"1","itemRating":"1","itemImage":"1","itemImgSize":"Large","itemImageMainCaption":"1","itemImageMainCredits":"1","itemIntroText":"1","itemFullText":"1","itemExtraFields":"1","itemDateModified":"1","itemHits":"1","itemCategory":"1","itemTags":"1","itemAttachments":"1","itemAttachmentsCounter":"1","itemVideo":"1","itemVideoWidth":"","itemVideoHeight":"","itemAudioWidth":"","itemAudioHeight":"","itemVideoAutoPlay":"0","itemVideoCaption":"1","itemVideoCredits":"1","itemImageGallery":"1","itemNavigation":"1","itemComments":"1","itemTwitterButton":"1","itemFacebookButton":"1","itemGooglePlusOneButton":"1","itemAuthorBlock":"1","itemAuthorImage":"1","itemAuthorDescription":"1","itemAuthorURL":"1","itemAuthorEmail":"0","itemAuthorLatest":"1","itemAuthorLatestLimit":"5","itemRelated":"1","itemRelatedLimit":"5","itemRelatedTitle":"1","itemRelatedCategory":"0","itemRelatedImageSize":"0","itemRelatedIntrotext":"0","itemRelatedFulltext":"0","itemRelatedAuthor":"0","itemRelatedMedia":"0","itemRelatedImageGallery":"0","itemK2Plugins":"1","catMetaDesc":"","catMetaKey":"","catMetaRobots":"","catMetaAuthor":""}

My MENU item is type CategoryBlogList, and link to Category A.
Articles are displayed as follows: Title=YES, ... (just like set in Joomla default option for Articles.
And now, if I set Display Title=NO in Joomla default option for Articles, the Title is no more displayed.

Any setting missing? Anything to do in Joomla?
Thank you.

I think that you mean that your Menu Type is Categories as in K2 Categories, right?
Once you have imported all your content to K2 you should change the menu item types as well to bring the items with the parameters you have set in K2 and not the Joomla! articles.

Image 01-catDEFAULT.jpg
Joomla Article Management Options
Title: show
...

Definition for Menu item CASI and COMMENTI DIVULGATIVI:
menutype: category blog
category: CASI
linking to www.heldercamara.it/INTRANET/SVILUPPO/rete-progetto-diritti-milano/casi.html

Menu item: COMMENTI DIVULGATIVI
menutype: category blog
category: COMMENTI DIVULGATIVI
linking to www.heldercamara.it/INTRANET/SVILUPPO/rete-progetto-diritti-milano/commenti-divulgativi.html

Image 02-k2EditCat x catCASI.jpg and 03-k2EditCat x catCASI.jpg
In K2 I set my options for articles of category CASI,
K2 EditCategory CASI
Item view options in category listings
Title: hide
...
Same in Item view Option

Image 05-k2EditCat x catCOMMENTI DIVULGATIVII.jpg
In K2 I set my options for articles of category COMMENTI DIVULGATIVII,
K2 EditCategory COMMENTI DIVULGATIVI
Item view options in category listings
Title: show
...

Image 04-catCASI commenti.jpg and 07-catCOMMENTI article.jpg
As you can see in the images or in the links mentioned above, the Title is always displayed, as set in Joomla Article Management Options
(tried also with other options).

You will have to change the menu type for the CASI category from Category Blog to K2 Category. The pages you are seeing in the frontend are the ones of the Joomla Articles and not the K2 categories.

The parameters you have set in K2 categories are the correct ones but as long as your pages link to non K2 items how do you expect to show the right options?