Pass value using NSCoding Protocol

Question

I'm trying to pass data to detail page upon clicking a cell inside UITabelViewCell using NSCoding Protocol

NSCoder *coder =[[NSCoder alloc] init];

[coder encodeObject:@"value" forKey:@"title"];

[coder encodeObject:cell.remainderContentLabel.text forKey:@"content"];

[coder encodeObject:cell.remainderDateTimeLabel.text forKey:@"datetime"];

[coder encodeObject:cell.remainterImageView.image forKey:@"image"];

RemainderDetailViewController *detailVC = [[RemainderDetailViewController alloc] initWithCoder:coder];

[self.navigationController pushViewController:detailVC animated:YES];

But it is crashing msg is

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -encodeObject:forKey: cannot be sent to an abstract object of class NSCoder: Create a concrete instance!'

In detail page decoding is done by

- (id) initWithCoder:(NSCoder *) aDecoder {

    if(self = [super initWithCoder:aDecoder]) {

      _remainderTitle.text =  [aDecoder decodeObjectForKey:@"title"];

      _remainderDetails.text =  [aDecoder decodeObjectForKey:@"content"];

      _dateAndTime.text =   [aDecoder decodeObjectForKey:@"datetime"];

      _remainderImage.image =  [aDecoder decodeObjectForKey:@"image"];

    }

    return self;
}

How to use

- (void)encodeWithCoder:(NSCoder *)encoder

What is wrong im doing? Class is confirmed to NSCopying protocol

https://stackoverflow.com/questions/22168753/unrecognized-selector-sent-to-instance-while-archiving-data-nscoding ? But to pass data inside a UITableViewCell, I don't see why use NSCoding. — Larme, Jul 31 '17 at 12:23
when this encodeWithCoder getting called? how can i push the VC — Saranjith, Jul 31 '17 at 12:24
The detail page is needed to be reused in many places. So i can simply write initWithCoder from anywhere — Saranjith, Jul 31 '17 at 12:26
I read more carefully your code, and the `RemainderDetailViewController` code doesn't make really sense. `RemainderDetailViewController` has a xib? A storyboard ? — Larme, Jul 31 '17 at 12:26
Then how can i give initWithCoder if im using segue. It will be performSegue — Saranjith, Jul 31 '17 at 12:28
Do not use `initWithCoder:`. I don't think it's usefull in your code. It's quite an "advance" knowledge to have, but if you are missing the `performSegue:`/Storyboard uses to pass data or reuses sames ViewController with different data/options, then study them instead. — Larme, Jul 31 '17 at 12:30
Good. All thus i have tried. Okey can you please give an example where i can implement the NSCoding. Because i want to go in some deep. — Saranjith, Jul 31 '17 at 12:35
http://nshipster.com/nscoding/ Use it to save data, not really UIViewController (for 99% of the cases). — Larme, Jul 31 '17 at 12:36

score 1 · Answer 1 · answered Aug 01 '17 at 05:37

AS I know - (id) initWithCoder:(NSCoder *) aDecoder is called when you load a ViewController from storyboard. If you want to push to a ViewController in the storyboard using code. You can

RemainderDetailViewController *detailVC = [[UIStoryboard storyboardWithName:@"XXX" bundle:nil] instantiateViewControllerWithIdentifier:@"yourControllerIdentifier"];
detailVC.paramDic = @{...};
[self.navigationController pushViewController:detailVC animated:YES];

The "yourControllerIdentifier" is defined in the storyboard.You can't initialize a ViewController by using the method directly. And in the destination ViewController - (id) initWithCoder:(NSCoder *) aDecoder can be fired. You can do some initial work in it.

score 0 · Answer 2 · edited Jun 20 '20 at 09:12

Use a dictionary to pass a bunch of objects.

But if you want to use an archive, read the documentation of NSCoder, it says:

The NSCoder abstract class declares the interface used by concrete subclasses to transfer objects and other values between memory and some other format.

…

The concrete subclasses provided by Foundation for these purposes are NSArchiver, NSUnarchiver, NSKeyedArchiver, NSKeyedUnarchiver, and NSPortCoder.

Use NSKeyedArchiver.

Pass value using NSCoding Protocol

2 Answers2