NSUserDefaults在UITableViewController中添加行

Question

I am trying to use NSUserDefaults to store a UITextField text and to retrieve it in another controller after you press Done button while editing.

in the controller where the user put information i code this :

-(IBAction)confirmAction:(id)sender{

UIViewController *prevVC = [self.navigationController.viewControllers objectAtIndex:1];
[self.navigationController popToViewController:prevVC animated:YES];

NSUserDefaults *try = [NSUserDefaults standardUserDefaults];
[try setObject:self.nameTextField.text forKey:@"name"];
[try synchronize];

}

and in the other controller i use this :

-(void)doneAction:(id)sender{

[self.tableView setEditing:NO animated:NO];

self.navigationItem.leftBarButtonItem = nil;

self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemEdit target:self action:@selector(editButtonClicked:)];

NSUserDefaults *try = [NSUserDefaults standardUserDefaults];
[ingredients addObject:[try stringForKey:@"name"]];



}

why i can't see any results. nothing is added in the tableview. why? did i write something wrong?

Answer 1

The most likely reason why you do not see the changes is that the UITableView does not know that you have added a new item to the ingredients array. In MVC terms, your controller made changes to the model, but it did not notify the view of that change.

You need to call [self.tableView reloadData]; at the end of your doneAction: method:

-(void)doneAction:(id)sender {
    [self.tableView setEditing:NO animated:NO];
    self.navigationItem.leftBarButtonItem = nil;
    self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemEdit target:self action:@selector(editButtonClicked:)];
    NSUserDefaults *try = [NSUserDefaults standardUserDefaults];
    [ingredients addObject:[try stringForKey:@"name"]];
    [self.tableView reloadData];
}

Answer 2

You should add [self.tableView reloadData]; after [ingredients addObject:[try stringForKey:@"name"]];