Question

我有2个视图控制器-1，用于输入用户的值，另一个用于在表视图中显示值。编码如下：

这用于显示通知传递的值：

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;
}

这是用于在名为source.m -

的视图控制器中输入用户的数据

- (IBAction)senddata:(id)sender
{
    NSDictionary *dict=[NSDictionary dictionaryWithObject:_nametextfield.text forKey:@"USERNAME"];
    [[NSNotificationCenter defaultCenter]postNotificationName:@"TestNotification" object:nil userInfo:dict];
}

当我尝试运行我的应用程序时，它没有在表视图控制器中显示输入的值。为什么会这样？提前谢谢......

Answer 1

你的代码看起来不错。但是你真的想在每次收到通知时重新实例化阵列吗？或者您只想实例化一次数组，然后通过通知添加值？如果你想要的是最后一个是我的解决方案：

接收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

发布通知的viewcontroller

@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

Answer 2

喜欢并试试这个

- (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];
}

何时使用通知传递值？

2 个答案: