Wrong indexPath.row after reloadData - ios

Question

I'm trying to get the indexPath.row of a button clicked inside a tableView row.
When the user clicks this button I get the index.row corresponding to the button very well, but when I add more objects to the source array to create more cells by calling reloadData, the rowButtonClicked in each cell it's no longer giving me the correct indexPath.row in example I press the index 20 and now the printed indexPath.row is 9.
In cellForRowAtIndexPath to add the event to the button:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
lBtnWithAction = [[UIButton alloc] initWithFrame:CGRectMake(liLight1Xcord + 23, 10, liLight1Width + 5, liLight1Height + 25)];
lBtnWithAction.tag = ROW_BUTTON_ACTION;
lBtnWithAction.titleLabel.font = luiFontCheckmark;
lBtnWithAction.tintColor = [UIColor blackColor];
lBtnWithAction.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin;
[cell.contentView addSubview:lBtnWithAction];
}
else
{
lBtnWithAction = (UIButton *)[cell.contentView viewWithTag:ROW_BUTTON_ACTION];
}
//Set the tag
lBtnWithAction.tag = indexPath.row;
//Add the click event to the button inside a row
[lBtnWithAction addTarget:self action:#selector(rowButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
return cell;
}
To do something with the clicked index:
-(void)rowButtonClicked:(UIButton*)sender
{
//Get the index of the clicked button
NSLog(#"%li", (long)sender.tag);
[self doSomething:(long)sender.tag];
}
Constants.h
#define ROW_BUTTON_ACTION 9
Why it is giving an incorrect index when I change the initial items of the tableView? Is there a way to solve this issue?

Answer 1

It looks like you're messing up button tags. Once you set the tag
lBtnWithAction.tag = indexPath.row;
you won't be able to get button correctly with
lBtnWithAction = (UIButton *)[cell.contentView viewWithTag:ROW_BUTTON_ACTION];
(assuming ROW_BUTTON_ACTION is a constant). lBtnWithAction will be nil all the time except when indexPath.row is equal to ROW_BUTTON_ACTION.
I would propose to subclass UITableViewCell, add a button-property there and then just refer to it directly instead of searching by tag. In this case you'll be able to use tags for buttons freely :) –
#interface UIMyTableViewCell : UITableViewCell
#property (nonatomic, strong, nonnull) UIButton *lBtnWithAction;
#end
And then in cellForRowAtIndexPath:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UIMyTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UIMyTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
[cell.lBtnWithAction addTarget:self action:#selector(rowButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
}
cell.lBtnWithAction.tag = indexPath.row;
return cell;
}

Answer 2

You can simply update you line -
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
to
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath]

Answer 3

My take on this will be subclassing the UITableViewCell and providing a delegate for it to respond.
code:
//MyCoolTablewViewCell.h
#protocol MyCoolProtocol<NSObject>
-(void)youTouchedMyCoolCell:(MyCoolTableViewCell __nonnull *)myCoolCell;
#end
#interface MyCoolTableViewCell:UITableViewCell
#property(nonatomic, weak,nullable) id<MyCoolProtocol>myCooldelegate;
#end
//MyCoolTablewViewCell.m
#interface MyCoolTableViewCell(){
UIButton *mySuperCoolButton;
}
#end
#implementation MyCoolTablewViewCell
-(id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier{
if(!(self = [super initWithStyle:style reuseIdentifier:reuseIdentifier])){
return nil;
}
// init your stuff here
// init button
mySuperCoolButton = [UIBUtton buttonWithType:UIButtonTypeCustom];
[mySuperCoolButton addTarget:self action:#selector(tappedMyCoolButton:) forControlEvents:UIControlEventTouchUpInside];
return self;
}
- (void)tappedMyCoolButton:(id)sender{
if([_myCoolDelegate respondToSelector:#selector(youTouchedMyCoolCell:)]){
[_myCoolDelegate youTouchedMyCoolCell:self];
}
}
#end
then in your controller
// whatEverController.m
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
// get the cell
cell = [tableView dequeueReusableCellWithIdentifier:#"myCoolIdentifier"forIndexPath:indexPath];
cell.myCooldelegate = self;
}
-(void)youTouchedMyCoolCell:(MyCoolTableViewCell *)myCoolCell{
NSIndexPath *myCoolIndexPath = [_tableView indexPathForCell:myCoolCell];
// then do whatever you want with the index path
}