I can't delete item from list Xcode - ios

Question

Hi I am trying out Xcode and I want to delete items from the list. I can get the delete button to show but once the delete button is clicked it wont delete. The delete code is at the end of the code. There is something missing in the deleting part of the code and I am not really sure what it is.
#import "ToDoListTableViewController.h"
#import "ToDoItem.h"
#import "AddToDoItemViewController.h"
#interface ToDoListTableViewController ()
#property NSMutableArray *toDoItems;
#end
#implementation ToDoListTableViewController
- (void)loadInitialData {
ToDoItem *item1 = [[ToDoItem alloc] init];
item1.itemName = #"Buy milk";
[self.toDoItems addObject:item1];
ToDoItem *item2 = [[ToDoItem alloc] init];
item2.itemName = #"Buy eggs";
[self.toDoItems addObject:item2];
ToDoItem *item3 = [[ToDoItem alloc] init];
item3.itemName = #"Read a book";
[self.toDoItems addObject:item3];
}
- (IBAction)unwindToList:(UIStoryboardSegue *)segue {
AddToDoItemViewController *source = [segue sourceViewController];
ToDoItem *item = source.toDoItem;
if (item != nil) {
[self.toDoItems addObject:item];
[self.tableView reloadData];
}
}
- (void)viewDidLoad {
[super viewDidLoad];
self.toDoItems = [[NSMutableArray alloc] init];
[self loadInitialData];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
// Return the number of sections.
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:
(NSInteger)section {
// Return the number of rows in the section.
return [self.toDoItems count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath: (NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"ListPrototypeCell" forIndexPath:indexPath];
// Configure the cell...
ToDoItem *toDoItem = [self.toDoItems objectAtIndex:indexPath.row];
cell.textLabel.text = toDoItem.itemName;
if (toDoItem.completed) {
cell.accessoryType = UITableViewCellAccessoryCheckmark;
} else {
cell.accessoryType = UITableViewCellAccessoryNone;
}
return cell;
}
// Override to support editing the table view.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
// Delete the row from the data source
[tableView deleteRowsAtIndexPaths:#[indexPath] withRowAnimation:UITableViewRowAnimationFade];
} else if (editingStyle == UITableViewCellEditingStyleInsert) {
// Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
}
}

Answer 1

In your tableView:(UITableView *)tableView commitEditingStyle: (UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath method you only delete the cell. You also have to delete your actual data.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
// Delete data from array
[self.toDoItems removeObjectAtIndex:indexPath.row];
// Delete the row from the data source
[tableView deleteRowsAtIndexPaths:#[indexPath] withRowAnimation:UITableViewRowAnimationFade];
} else if (editingStyle == UITableViewCellEditingStyleInsert) {
// Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
}
}

Answer 2

When deleteRowsAtIndexPaths gets called it refreshes the tableViews data, which then calls cellForRowAtIndexPath. Now that you didn't change the data, nothing will change in the tableView.

Answer 3

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
// Delete data from array
[self.toDoItems removeObjectAtIndex:indexPath.row];
// Reload table -> it's OK
[tableView reloadData];
} else if (editingStyle == UITableViewCellEditingStyleInsert) {
// Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
}
}