Swipe To Delete TableView Row

Question

I have my array:

self.colorNames = [[NSArray alloc] 
initWithObjects:@"Red", @"Green",
@"Blue", @"Indigo", @"Violet", nil];

I've tried everything I can find, but there's always errors. I want to be able to swipe so that the delete button appears, and then press the delete button and have that row removed.

Full code (everything relating to the table):

// HEADER FILE
@interface ViewController : UIViewController <UITableViewDelegate, UITableViewDataSource> {

  IBOutlet UITableView *tableView;
    NSMutableArray *colorNames;

}
@property (strong, nonatomic) NSArray *colorNames;


@end

// IMPLEMENTATION

#import "ViewController.h"

@implementation ViewController

@synthesize colorNames; 

- (void)viewDidLoad {

    [super viewDidLoad];

    self.colorNames = [[NSMutableArray alloc] 
    initWithObjects:@"Red", @"Green",
    @"Blue", @"Indigo", @"Violet", nil];

    [super viewDidLoad];
    //[tableView setEditing:YES animated:NO];
}


- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return 1;
 }

// Customize the number of rows in the table view.
- (NSInteger)tableView:(UITableView *)tableView  numberOfRowsInSection:(NSInteger)section {
    int count = [colorNames count];
    return count;
}

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

}  

 // Customize the appearance of table view cells.
 - (UITableViewCell *)tableView:(UITableView *)tableView 
 cellForRowAtIndexPath:(NSIndexPath *)indexPath {

 static NSString *CellIdentifier = @"Cell";

 UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

 if (cell == nil) {
     cell = [[UITableViewCell alloc]
             initWithStyle:UITableViewCellStyleDefault
             reuseIdentifier:CellIdentifier];

 }
     // Configure the cell.
     cell.textLabel.text = [self.colorNames objectAtIndex: [indexPath row]];

 return cell;

 }

Answer 1

You have to implement the necessary UITableViewDelegate and UITableViewDataSource methods.

First, add this:

- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath {
    return YES;
}

Then:

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        //remove the deleted object from your data source.
        //If your data source is an NSMutableArray, do this
        [self.dataArray removeObjectAtIndex:indexPath.row];
        [tableView reloadData]; // tell table to refresh now
    }
}

Answer 2

For a start, your colorNames should be an NSMutableArray rather than an NSArray. You can’t add or remove objects from a regular (non-mutable) array; you’d have to recreate it each time you made a change. Switching that will make this easier. For your implementation of -tableView:commitEditingStyle:forRowAtIndexPath:, you’ll then be able to do something like this:

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    if(editingStyle == UITableViewCellEditingStyleDelete)
    {
        [colorNames removeObjectAtIndex:indexPath.row];
        [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationLeft];
    }
}

Answer 3

Implement the following method:

- (UITableViewCellEditingStyle)tableView:(UITableView *)tableView editingStyleForRowAtIndexPath:(NSIndexPath *)indexPath
{
    return UITableViewCellEditingStyleDelete;
}

Answer 4

Swift 3 and Swift 4 answer without using reloadData

I prefer using deleteRows instead of using reloadData.

func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
    // Enables editing only for the selected table view, if you have multiple table views
    return tableView == yourTableView
}

func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
    if editingStyle == .delete {
        // Deleting new item in the table
        yourTableView.beginUpdates()
        yourDataArray.remove(at: indexPath.row)
        yourTableView.deleteRows(at: [indexPath], with: .automatic)
        yourTableView.endUpdates()
    }
}