Working with UITableView Sections and Rows: Increasing Label Values Separately
In this article, we will delve into the world of UITableView sections and rows. Specifically, we’ll explore how to increase label values separately for each row within a section. This is achieved by using a combination of custom cells, actions, and event handling.
Understanding UITableView Structure
A UITableView consists of sections and rows. Each section represents a group of related data, while each row represents an individual item within that section. When you select a cell in the table view, it can trigger various actions based on your specific requirements.
The Code
We’ll use the provided code snippet as a starting point for our implementation. The code is written in Objective-C and utilizes UIKit framework components.
SectionIndexTitlesForTableView Method
- (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView {
NSArray *toBeReturned = [NSArray arrayWithArray:
[@"A|B|C|D|E|F|G|H|I|J|K|L|M|N|O|P|Q|R|S|T|U|V|W|X|Y|Z"
componentsSeparatedByString:@"|"]];
return toBeReturned;
}
This method returns an array of section titles for the table view. In this case, we have a single section with 32 titles.
Cell For Row Method
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *MyIdentifier = @"MyIdentifier";
LocationsCustomCell *cell = (LocationsCustomCell *)[tableView dequeueReusableCellWithIdentifier:MyIdentifier];
if(cell == nil) {
[[NSBundle mainBundle] loadNibNamed:@"LocationsCustomCell" owner:self options:nil];
cell = locationCustomcell;
}
@try {
if(indexPath.section < [arrayOfCharacters count]) {
NSString *sortedStr = [[objectsForCharacters objectForKey:[arrayOfCharacters objectAtIndex:indexPath.section]] objectAtIndex:indexPath.row];
if([sortedStr isKindOfClass:[NSNull class]]) {
cell.locationNameLabel.text=@"";
} else {
cell.locationNameLabel.text=sortedStr;
cell.locationNameLabel.textColor=[UIColor blackColor];
}
}
}
@catch (NSException *exception) {
}
sectionNo = indexPath.section;
cell.plusButn.tag = sectionNo*100+indexPath.row;
cell.minusButn.tag = sectionNo*100+indexPath.row;
cell.locationCountLabel.tag=sectionNo*100+indexPath.row;
[cell.plusButn addTarget:self action:@selector(plusButnPressed:) forControlEvents:UIControlEventValueChanged];
[cell setSelectionStyle:UITableViewCellSelectionStyleNone]; // Set selection style to none
return cell;
}
This method returns a custom UITableViewCell instance. The cell is reused from the table view’s pool, and its properties are updated based on the row index path.
plusButnPressed Method
- (void)plusButnPressed:(id)sender {
// Get the current row index path
NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:[sender locationInView:self.tableView]];
// Increment the label value
int a = [self.tableView cellForRowAtIndexPath:indexPath].locationCountLabel.text.intValue;
a++;
// Update the label text
[self.tableView cellForRowAtIndexPath:indexPath].locationCountLabel.text = [NSString stringWithFormat:@"%d",a];
}
This method is called when the plusButn button is pressed. It retrieves the current row index path and increments the label value by 1.
minusButtonPressed Method
- (void)minusButtonPressed:(id)sender {
// Get the current row index path
NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:[sender locationInView:self.tableView]];
// Decrement the label value
int a = [self.tableView cellForRowAtIndexPath:indexPath].locationCountLabel.text.intValue;
a--;
// Update the label text
[self.tableView cellForRowAtIndexPath:indexPath].locationCountLabel.text = [NSString stringWithFormat:@"%d",a];
}
This method is called when the minusButn button is pressed. It retrieves the current row index path and decrements the label value by 1.
The Solution
To increase label values separately for each row within a section, we need to add two actions to the buttons in our custom cell: plusButtonPressed and minusButtonPressed. We then handle these events in the view controller’s implementation file.
// In ViewController.m
- (void)buttonPressed:(id)sender withEvent:(UIEvent *)event {
UITouch *touch = [[event touches] anyObject];
CGPoint location = [touch locationInView:self.tableView];
NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:location];
// Get the current row index path
int a = [[self.tableView cellForRowAtIndexPath:indexPath].locationCountLabel.text intValue];
if ([sender isEqual:cell.plusButn]) {
a++;
} else if ([sender isEqual:cell.minusButn]) {
a--;
}
[self.tableView cellForRowAtIndexPath:indexPath].locationCountLabel.text = [NSString stringWithFormat:@"%d",a];
}
The Final Code
// In ViewController.m
- (void)viewDidLoad {
[super viewDidLoad];
// Create and configure the table view
self.tableView = [[UITableView alloc] initWithFrame:self.view.bounds style:UITableViewStyleGrouped];
self.tableView.delegate = self;
self.tableView.dataSource = self;
[self.tableView registerClass:[LocationsCustomCell class] forCellReuseIdentifier:@"LocationsCustomCell"];
[self.tableView reloadData];
// Add actions to the buttons in our custom cell
if (cell == nil) {
[[NSBundle mainBundle] loadNibNamed:@"LocationsCustomCell" owner:self options:nil];
cell = locationCustomcell;
[cell.plusButn addTarget:self action:@selector(plusButtonPressed:) forControlEvents:UIControlEventTouchUpInside];
[cell.minusButn addTarget:self action:@selector(minusButtonPressed:) forControlEvents:UIControlEventTouchUpInside];
}
}
- (void)buttonPressed:(id)sender withEvent:(UIEvent *)event {
UITouch *touch = [[event touches] anyObject];
CGPoint location = [touch locationInView:self.tableView];
NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:location];
// Get the current row index path
int a = [[self.tableView cellForRowAtIndexPath:indexPath].locationCountLabel.text intValue];
if ([sender isEqual:cell.plusButn]) {
a++;
} else if ([sender isEqual:cell.minusButn]) {
a--;
}
[self.tableView cellForRowAtIndexPath:indexPath].locationCountLabel.text = [NSString stringWithFormat:@"%d",a];
}
By using this approach, you can increase label values separately for each row within a section in your UITableView.
Last modified on 2024-04-04