Can I have a UIButton's action method take a second parameter? - ios

Question

I want to place a button in each cell of a table. I want the target to be a class that I'm using to handle all of the API calls. I want the button's method to be in the friendController class, not in the UITableView's View Controller.
[cell.deleteButton addTarget:friendController
action:#selector(deleteFriend: forID:cell.idNumber)
forControlEvents:UIControlEventTouchUpInside];
Where friendController is the class with the API calls, and cell.idNumber is an instance variable of each cell containing the ID number of the user associated with that cell.
I know (well, I presume) that I could set the cell itself as the target and then have a method which looks like:
-(IBAction)deleteFriend:(id)sender {
[friendController deleteFriend:self.idNumber];
}
Is that correct? It doesn't seem like an elegant way of doing this. Is there a way to do it the way I want to, or is there a better way to do it?
EDIT: I emboldened the last crucial part of my question. I want the button's action to be a method in another class (friendController). friendController is a class I created to house all of the API calls and business logic. If I set the target to friendController, must the action be a method in that class?

Answer 1

You can do this two ways.
Subclassing UIButton
The first would be to subclass UIButton and create a property for the idNumber. So you would first set the property like so:
cell.deleteButton.idNumber = /* set id here */
[cell.deleteButton addTarget:friendController
action:#selector(deleteFriend:)
forControlEvents:UIControlEventTouchUpInside];
and then access it inside your deleteFriend: method:
- (IBAction)deleteFriend:(id)sender {
YourButtonClass *button = (YourButtonClass *)sender;
[friendController deleteFriend:button.idNumber];
}
Retrieve the idNumber directly from the cell
Described in this post you can grab the index path of the button's cell and then access the idNumber from there.

Answer 2

Use the tag property of the button.
cell.deleteButton.tag = cell.idNumber;
[cell.deleteButton addTarget:friendController action:#selector(deleteFriend:) forControlEvents:UIControlEventTouchUpInside];
In the method, you can use the tag to retrieve the cell idNumber
-(IBAction)deleteFriend:(id)sender {
int idNumber = ((UIButton *) sender).tag;
[friendController deleteFriend: idNumber];
}

Answer 3

With 2 parameters indicating the control that sends the message and the event that triggered the message:
action:#selector(buttonAction:Second:)
- (void)viewDidLoad
{
[super viewDidLoad];
UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[btn addTarget:self action:#selector(buttonAction:Second:) forControlEvents:UIControlEventTouchUpInside];
}
- (void)buttonAction:(NSString *)firstCharacter
Second:(NSNumber *)second
{
}

Answer 4

Since the button is inside a UITableViewCell, you might consider subclass a UITableViewCell with your property idNumber(I don't like reuse Tag because it can only be an integer) and a delegate:
#protocol MyTableViewCellDelegate;
#interface MyTableViewCell : UITableViewCell
#property (nonatomic, assign) NSInteger idNumber;
#property (nonatomic, weak) id<MyTableViewCellDelegate> delegate;
#end
#protocol MyTableViewCellDelegate <NSObject>
-(void) shouldDeleteFriendById:(NSInteger)idNumber;
#end
And handle the button action inside the MyTableViewCell implementation:
- (void) myInit
{
UIButton* button = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
[button addTarget:self action:#selector(onButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
[self addSubview:button];
}
- (IBAction)onButtonClicked:(id)sender
{
[self.delegate shouldDeleteFriendById:self.idNumber];
}
Then implement cell's delegate in your tableViewController:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
MyTableViewCell *cell = (MyTableViewCell*)[tableView dequeueReusableCellWithIdentifier:#"MyCell" forIndexPath:indexPath];
// Configure the cell...
cell.idNumber = indexPath.row;
cell.delegate = self;
return cell;
}
- (void) shouldDeleteFriendById:(NSInteger)idNumber
{
NSLog(#"should delete by id:%d", idNumber);
}