Ho wto pass values using notification? - ios

Question

I have 2 view controllers-1 for entering the value from the user and another to display value in a table view. The coding goes as follows:
This is for displaying the value passed by the notification:
ListTableViewContrller.m
#property(strong,nonatomic)NSMutableArray *namearray;
#end
#implementation ListTableViewController
- (void)viewDidLoad {
[super viewDidLoad];
[[NSNotificationCenter defaultCenter]addObserver:self selector:#selector(receieveTestNotificatiom:) name:#"TestNotification" object:nil];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
-(void)receieveTestNotificatiom:(NSNotification *)notification
{
_namearray=[[NSMutableArray alloc]initWithObjects:[notification.userInfo objectForKey:#"USERNAME"], nil];
[self.tableView reloadData];
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return _namearray.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"cellreuse" forIndexPath:indexPath];
cell.detailTextLabel.text=[_namearray objectAtIndex:indexPath.row];
return cell;
}
This is for entering the data from the user in a view controller named as source.m-
- (IBAction)senddata:(id)sender
{
NSDictionary *dict=[NSDictionary dictionaryWithObject:_nametextfield.text forKey:#"USERNAME"];
[[NSNotificationCenter defaultCenter]postNotificationName:#"TestNotification" object:nil userInfo:dict];
}
When i try to run my application, it is not displaying the entered value in the table view controller. Why is it so? Thanks in advance......

Answer 1

do like and try this
- (void)viewDidLoad {
[super viewDidLoad];
// allocate the memory here
_namearray=[NSMutableArray new];
[[NSNotificationCenter defaultCenter]addObserver:self selector:#selector(receieveTestNotificatiom:) name:#"TestNotification" object:nil];
}
-(void)receieveTestNotificatiom:(NSNotification *)notification
{
NSString *value = [NSString stringwithFormat:#"%#",[notification.userInfo objectForKey:#"USERNAME"]];
NSLog(#"%# value", [notification userInfo]);
[_namearray addobject:value];
[self.tableView reloadData];
}

Answer 2

your code looks ok. but do you really want to reinstantiate the array every time you receive a notification? or do you want to instantiate the array only once and then add values you get via notification? if the last is what you want here is my solution:
receiving tableviewcontroller
#interface TableViewController ()
#property (strong, nonatomic) NSMutableArray *names;
#end
#implementation TableViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.tableView.estimatedRowHeight = 44.0;
self.tableView.rowHeight = UITableViewAutomaticDimension;
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(receivedNotification:) name:#"NEW_NAME_NOTIFICATION" object:nil];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return self.names.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"NameCell" forIndexPath:indexPath];
cell.textLabel.text = self.names[indexPath.row];
return cell;
}
- (void)receivedNotification:(NSNotification *)notification {
[self.names addObject:notification.userInfo[#"value"]];
[self.tableView insertRowsAtIndexPaths:#[[NSIndexPath indexPathForRow:self.names.count - 1 inSection:0]] withRowAnimation:UITableViewRowAnimationAutomatic];
}
- (NSMutableArray *)names {
if (!_names) {
_names = [NSMutableArray array];
}
return _names;
}
#end
viewcontroller that posts notifications
#interface NewNameViewController ()
#property (weak, nonatomic) IBOutlet UITextField *textField;
#end
#implementation NewNameViewController
- (IBAction)doneBarButtonItemTapped:(UIBarButtonItem *)sender {
[self.presentingViewController dismissViewControllerAnimated:YES completion:^{
[[NSNotificationCenter defaultCenter] postNotificationName:#"NEW_NAME_NOTIFICATION" object:nil userInfo:#{#"value": self.textField.text}];
}];
}
#end