iOS - Table View

Use of Table View

It is used for displaying a vertically scrollable view which consists of number of cells (generally reusable cells). It has special features like headers, footers, rows and section.

Important properties

• delegate
• dataSource
• rowHeight
• sectionFooterHeight
• sectionHeaderHeight
• separatorColor
• tableHeaderView
• tableFooterView

Important methods

- (UITableViewCell *)cellForRowAtIndexPath:(NSIndexPath *)indexPath

- (void)deleteRowsAtIndexPaths:(NSArray *)indexPaths
   withRowAnimation:(UITableViewRowAnimation)animation

- (id)dequeueReusableCellWithIdentifier:(NSString *)identifier

- (id)dequeueReusableCellWithIdentifier:(NSString *)identifier
   forIndexPath:(NSIndexPath *)indexPath

- (void)reloadData

- (void)reloadRowsAtIndexPaths:(NSArray *)indexPaths
   withRowAnimation:(UITableViewRowAnimation)animation

- (NSArray *)visibleCells

Sample code and steps

1. Let's add a tableview in ViewController.xib as shown below.

2. Set delegate and dataSource to file owner for tableview by right clicking and selecting datasource and delegate. Setting dataSource is shown below.

3. Then create an IBOutlet for tableView and name it as myTableView. It is shown in following images.

4. Then add an NSMutableArray for holding the data to be displayed in the table view.

5. Our ViewController should adopt the UITableViewDataSource and UITableViewDelegate protocols. The ViewController.h should look as shown below.

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController<UITableViewDataSource,
UITableViewDelegate>
{
    
    IBOutlet UITableView *myTableView;
    NSMutableArray *myData;
}

@end

6. We should implement the required tableview delegate and dataSource methods. The updatedViewController.m is as follows

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    // table view data is being set here 
    myData = [[NSMutableArray alloc]initWithObjects:
    @"Data 1 in array",@"Data 2 in array",@"Data 3 in array",
    @"Data 4 in array",@"Data 5 in array",@"Data 5 in array",
    @"Data 6 in array",@"Data 7 in array",@"Data 8 in array",
    @"Data 9 in array", nil];
    // Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark - Table View Data source 
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:
  (NSInteger)section{
    return [myData count]/2;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:
  (NSIndexPath *)indexPath{
    static NSString *cellIdentifier = @"cellID";
    
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:
    cellIdentifier];
    if (cell == nil) {
        cell = [[UITableViewCell alloc]initWithStyle:
        UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
    }
    NSString *stringForCell;
    if (indexPath.section == 0) {
        stringForCell= [myData objectAtIndex:indexPath.row];

    }
    else if (indexPath.section == 1){
        stringForCell= [myData objectAtIndex:indexPath.row+ [myData count]/2];

    }
    [cell.textLabel setText:stringForCell];
    return cell;
}

// Default is 1 if not implemented
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView{
    return 2;
}

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:
  (NSInteger)section{
    NSString *headerTitle;
    if (section==0) {
        headerTitle = @"Section 1 Header";
    }
    else{
        headerTitle = @"Section 2 Header";

    }
    return headerTitle;
}
- (NSString *)tableView:(UITableView *)tableView titleForFooterInSection:
  (NSInteger)section{
    NSString *footerTitle;
    if (section==0) {
        footerTitle = @"Section 1 Footer";
    }
    else{
        footerTitle = @"Section 2 Footer";
        
    }
    return footerTitle;
}

#pragma mark - TableView delegate

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:
 (NSIndexPath *)indexPath{
    [tableView deselectRowAtIndexPath:indexPath animated:YES];
    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
    NSLog(@"Section:%d Row:%d selected and its data is %@",
    indexPath.section,indexPath.row,cell.textLabel.text);
}


@end

7. Now when we run the application we'll get the following output.