Three20 : how to pass a class of objects between 2 views

Question

I have a TTableView. The items in this table a mapped to an url, so that when I click on an item, another view appear with informations about this item. All these informations a

Answer 1

The big problem with directly using TTURLAction is that you can't really use them with TTTableViewItem. The only way to really do it is override -didSelectObject:atIndexPath: and build your custom TTURLAction with your desired object in the query dictionary. But this breaks the nice separation of Model and View Controller, and gets complicated once you have multiple objects to pass.

Instead of this, I've been using a small category which automatically takes the userInfo property of the table item (which I set to whatever I need), and automatically adds it as a URL parameter.

And then you use this to retrieve it in your mapped view controller.

- (id)initWithNavigatorURL:(NSURL *)URL query:(NSDictionary *)query { 
if (self = [self initWithNibName:nil bundle:nil]) {
    id myPassedObject = [query objectForKey:@"__userInfo__"];
    // do the rest of your initlization
}
return self;

}

You can download it as a GitHub Gist here. The code is also below. We're considering merging this into the main branch at some point.

---

TTTableViewDelegate+URLAdditions.h

@interface TTTableViewDelegate(URLAdditions)

@end

---

TTTableViewDelegate+URLAdditions.m

#import "TTTableViewDelegate+URLAdditions.h"

@implementation TTTableViewDelegate(URLAdditions)

- (void)tableView:(UITableView*)tableView didSelectRowAtIndexPath:(NSIndexPath*)indexPath {
    id dataSource = (id)tableView.dataSource;
    id object = [dataSource tableView:tableView objectForRowAtIndexPath:indexPath];

    // Added section to automatically wrap up any TTTableItem userInfo objects.  If it is a dictionary, it gets sent directly
    // If it is not, it is put in a dictionary and sent as they __userInfo__ key
    if( [object isKindOfClass:[TTTableLinkedItem class]] ) {
        TTTableLinkedItem* item = object;

        if( item.URL && [_controller shouldOpenURL:item.URL] ) {
            // If the TTTableItem has userInfo, wrap it up and send it along to the URL
            if( item.userInfo ) {
                NSDictionary *userInfoDict;

                // If userInfo is a dictionary, pass it along else create a dictionary
                if( [item.userInfo isKindOfClass:[NSDictionary class]] ) {
                    userInfoDict = item.userInfo;
                } else {
                    userInfoDict = [NSDictionary dictionaryWithObject:item.userInfo forKey:@"__userInfo__"];
                }

                [[TTNavigator navigator] openURLAction:[[[TTURLAction actionWithURLPath:item.URL]
                                                         applyQuery:userInfoDict]
                                                        applyAnimated:YES]];
            } else {
                TTOpenURL( item.URL );
            }
        }

        if( [object isKindOfClass:[TTTableButton class]] ) {
            [tableView deselectRowAtIndexPath:indexPath animated:YES];
        }
        else if( [object isKindOfClass:[TTTableMoreButton class]] ) {
            TTTableMoreButton* moreLink = (TTTableMoreButton*)object;
            moreLink.isLoading = YES;
            TTTableMoreButtonCell* cell
            = (TTTableMoreButtonCell*)[tableView cellForRowAtIndexPath:indexPath];
            cell.animating = YES;
            [tableView deselectRowAtIndexPath:indexPath animated:YES];

            if( moreLink.model )
                [moreLink.model load:TTURLRequestCachePolicyDefault more:YES];
            else
                [_controller.model load:TTURLRequestCachePolicyDefault more:YES];
        }
    }

    [_controller didSelectObject:object atIndexPath:indexPath];
}

@end