'indexPath' undeclared (first use in this function)

Question

I have the following error. 'indexPath' undeclared (first use in this function).

Code. didSelectRowAtIndexPath

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {  

UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
UIActivityIndicatorView *spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle: UIActivityIndicatorViewStyleWhiteLarge];
cell.accessoryView = spinner;
[spinner startAnimating];
[spinner release];

[self performSelector:@selector(pushDetailView:) withObject:tableView afterDelay:0.1];
}

pushDetailView

- (void)pushDetailView:(UITableView *)tableView {

// Push the detail view here
[tableView deselectRowAtIndexPath:indexPath animated:YES];
//load the clicked cell.
DetailsImageCell *cell = (DetailsImageCell *)[tableView cellForRowAtIndexPath:indexPath];

//init the controller.
AlertsDetailsView *controller = nil;
if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad){
controller = [[AlertsDetailsView alloc] initWithNibName:@"DetailsView_iPad" bundle:nil];
} else {
controller = [[AlertsDetailsView alloc] initWithNibName:@"DetailsView" bundle:nil];
}

//set the ID and call JSON in the controller.
[controller setID:[cell getID]];

//show the view.
[self.navigationController pushViewController:controller animated:YES];
}

I think it's because I'm not parsing the indexPath value from didSelectRowAtIndexPath to pushDetailView but I don't know how to approach this.

Could someone please advise?

Thanks.

Answer 1

The problem is that you pushDetailView: method has no indexPath variable on it's scope.

Instead of

- (void)pushDetailView:(UITableView *)tableView {

You should make your method like this:

- (void)pushDetailView:(UITableView *)tableView andIndexPath: (NSIndexPath*) indexPath {

and then indexPath would be declared on the method scope.

Then, inside your didSelectRowAtIndexPath method, replace

[self performSelector:@selector(pushDetailView:) withObject:tableView afterDelay:0.1];

for the code bellow:

double delayInSeconds = 0.1;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
    [self pushDetailView: tableView andIndexPath: indexPath];
});

This uses GCD to execute the code after a delay, instead of the performSelector: withObject :afterDelay: and here is a nice post explaining why sometimes is better to opt for this aproach

Answer 2

Since you need to provide two arguments and perform after a delay package both arguments in an NSDictionary and pass it:

    NSDictionary *arguments = [NSDictionary dictionaryWithObjectsAndKeys:
    tableView, @"tableView", indexPath, @"indexPath", nil];
    [self performSelector:@selector(pushDetailView:) withObject:arguments afterDelay:0.1];
    ...

- (void)pushDetailView:(NSDictionary *)arguments {
    UITableView *tableView = [arguments objectForKey:@"tableView"];
    NSIndexPath *indexPath = [arguments objectForKey:@"indexPath"];
    ...

Or as @Felipe suggests, use GCD.