Question

I am showing an alert on UILongPressGestureRecognizer, the issue I am facing is that every time I have to click it three times to dismiss the alert while the alert should be dismissed on single click on button.

And due to this abnormal behavior, entries get duplicated in the core data..

The code I am using is as under:

In cellForRowAtIndexPath:

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    // NSString * cellValue;
    if (tableView == listTable) {
       cellValue = [listVehicles objectAtIndex:indexPath.row];
    } else { // handle search results table view
        cellValue = [filteredListItems objectAtIndex:indexPath.row];
    }

    static NSString *CellIdentifier = @"vlCell";

    VehicleListCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil) {
        NSLog(@"Cell Created");

        NSArray *nibObjects = [[NSBundle mainBundle] loadNibNamed:@"VehicleListCell" owner:nil options:nil];

        for (id currentObject in nibObjects) {
            if ([currentObject isKindOfClass:[VehicleListCell class]]) {
                cell = (VehicleListCell *)currentObject;
            }
        }

        UILongPressGestureRecognizer *pressRecongnizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(tableCellPressed:)];
        pressRecongnizer.minimumPressDuration = 0.5f;
        [cell addGestureRecognizer:pressRecongnizer];
        [pressRecongnizer release];
    }

    cell.textLabel.font = [UIFont systemFontOfSize:10];

    [[cell ignition] setImage:[UIImage imageNamed:@"ignition.png"]];
    [[cell direction] setImage:[UIImage imageNamed:@"south.png"]];

    cell.licPlate.text = cellValue;

    NSLog(@"cellvalue for cellforRow: %@", cell.licPlate.text);

    return cell;
}

In (void)tableCellPressed:(UILongPressGestureRecognizer *)recognizer method

- (void)tableCellPressed:(UILongPressGestureRecognizer *)recognizer {
    VehicleListCell* cell = (VehicleListCell *)[recognizer view];
    cellValueForLongPress = cell.licPlate.text;

    NSLog(@"cell value: %@", cellValueForLongPress);

    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:nil message:nil delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles: nil] ;

    [alert addButtonWithTitle:@"Add to Favourites"];
    [alert addButtonWithTitle:@"Take to Map"];

    [alert show];
}

In alert view method:

-(void)alertView:(UIAlertView *)alert clickedButtonAtIndex:(NSInteger)buttonIndex {

    NSString *title = [alert buttonTitleAtIndex:buttonIndex];

    NSManagedObjectContext *context = [app managedObjectContext];
    Favouritesdata * favourites = [NSEntityDescription insertNewObjectForEntityForName:@"Favouritesdata" inManagedObjectContext:context];

    if([title isEqualToString:@"Add to Favourites"])
    {
        NSLog(@"Added to favourites.");

        NSLog(@"cellValueForLongPress: %@", cellValueForLongPress);


        if (cellValueForLongPress <= 0) {
            NSLog(@"There is no value to save");
        }
        else {
            favourites.licenseplate = cellValueForLongPress;
        }

        [alert dismissWithClickedButtonIndex:0 animated:YES];
    }
    else if([title isEqualToString:@"Take to Map"])
    {
        NSLog(@"Go to MapView");
    }

    NSError *error;

    if (![context save:&error]) {
        NSLog(@"Error Occured");} 
}

What can be the issue?

Answer 1

The issue is that your long press gesture recogniser fires for each of the states, began, ended etc. If the state of the event is not the ‘began’ one then you should return and not perform the subsequent code.

- (void)tableCellPressed:(UILongPressGestureRecognizer *)recognizer { 
       if (recognizer.state != UIGestureRecognizerStateBegan) {
            return;
        }

       // ... rest of code
}