selector and PerformSelector - ios

Question

I have a UITableView with several sections. Each section contains a different set of data: phoneNumbers, addresses....
For each of those sets I have a model: PhoneNumber, Address. They're completely different but have some methods in common.
In my UITableView I have an array containing those models/classnames:
NSMutableArray *classNames;
In the viewDidLoad of my UITableView I do some initializations for all those sections:
//section 1: PhoneNumbers
phoneNumbers = [PhoneNumbers getAllIDs];
if (phoneNumbers && (phoneNumbers.count >0)) {
[classNames addObject:#"PhoneNumber"];
[dataIDs addObject:phoneNumbers];
}
I do this again for all the other sections/models:
//section 2: Addresses
addresses = [Address getAllIDs];
if (addresses && (addresses.count >0)) {
[classNames addObject:#"Address"];
[dataIDs addObject:addresses];
}
// section 3: .....
Ok so far for initialization. This looks good and works fine.
Then later on in my cellForRowAtIndexPath I'm retrieving the actual data via those ID's
NSInteger section = [indexPath section];
NSInteger row = [indexPath row];
NSArray *rows = [dataIDs objectAtIndex:section];
NSNumber *recordID = [rows objectAtIndex:row];
I then figure out in what class we have to fetch the actual data:
Class displayedDataClass = NSClassFromString ([classNames objectAtIndex:section]);
and get the data to populate the cell.
id displayedRecord = [[displayedDataClass alloc] init];
[displayedRecord getByID:recordID];
I can then set the labels in my cell using :
[cell.someLabel setText:[displayRecord fullDesciption]];
So far so good, I succesfully abstracted everything, the cellForRowAtIndexPathdoesn't need to know where things come from, as long as those classes respond to the methods for retrieving the data for the labels (in the case above fullDesciption)
Now I need an actionButton in every Cell performing some kind of action
To make sure I understood the concept of selectors and performSelection I just quick and dirty made in action in my TableView Class:
- (void) buttonTarget {
NSLog (#"yes");
}
And in my cellForRowAtIndexPath method created a button with the following target:
button addTarget:self action:#selector(buttonTarget) forControlEvents:UIControlEventTouchUpInside];
Ok, so far so good, things work like expected. But this is not what I really wanted. The action should not be performed here, but in the actual class (PhoneNumber,Address,...).
To keep things clean I made a model Action, containing the icon for the button, a description and the selector:
#interface Action : NSObject
#property (nonatomic, strong) NSString *description;
#property (nonatomic, strong) UIImage *icon;
#property (nonatomic ) SEL selector;
#end
In my PhoneNumber class (and similar classes) the action is set to the correct selector:
Action *phoneAction = [[Action alloc] init];
phoneAction.description = NSLocalizedString(#"Call", #"Call button description");
phoneAction.icon = [UIImage imageNamed:#"phone"];
phoneAction.selector = #selector(callPhone);
Of course callPhone is implemented in the PhoneNumber class.
In my TableView I then get the actions for that cell
action = [displayedRecord action];
I then try to use that selector in my Button:
[button addTarget:displayedRecord action:[action selector] forControlEvents:UIControlEventTouchUpInside];
But here things go wrong: we never arrive in that method and I get the following error:
[UIDeviceWhiteColor callPhone]: unrecognized selector sent to instance
0x874af90 2013-12-29 23:23:03.629 thinx[27242:907] * Terminating app
due to uncaught exception 'NSInvalidArgumentException', reason:
'-[UIDeviceWhiteColor callPhone]: unrecognized selector sent to
instance 0x874af90'

Answer 1

Sounds like you have a zombie. When you get an action being sent to an object that makes no sense, it usually means that your object is being deallocated before you can send a message to it.
In your case, you're adding "displayedRecord" as the target for your button.
In order for that to work, you need to keep a strong reference to displayedRecord call for the lifetime of your button object. What owns your displayedRecord object?
If you can't debug this from looking at your code you can use the zombies instrument to try to figure it out.

Answer 2

In your unrecognized selector error you sent the message to an object called UIDeviceWhiteColor. Does that class have a method called callPhone? It seems to me that displayedRecord is not pointing to the object you think it is.