Question

我有一个问题，我是iphone编程的首发，我不知道该怎么做。我必须让KVO观察者知道文本字段何时接收字符串并将字符串显示到带有动画的tableview中，我已经从文本字段中获取了字符串数组但我不知道如何将其显示在tableview中。所以有些人会非常感谢!!

继承我的代码：

- (BOOL)textFieldShouldReturn:(UITextField *)textField{
    NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
    if (!self.tasks) self.tasks = [NSMutableArray new];

    [self.tasks addObject:textField.text];
    [userDefaults setObject:self.tasks forKey:@"tasks"];
    NSLog(@"tasks:%@", [[NSUserDefaults standardUserDefaults]objectForKey:@"tasks"]);
    NSLog(@"number of tasks:%d", self.tasks.count); <-- this print works good, also the first one
    [textField addObserver:self forKeyPath:@"name" options:NSKeyValueObservingOptionNew context:NULL];
    [textField resignFirstResponder];
    return YES;
}

在tableviewcontroller中我只有这个（用于测试，但它不起作用:(）：

[self viewdidload];
    if (!self.TasksArray) self.TasksArray = [NSMutableArray new];
    self.TasksArray = [[NSUserDefaults standardUserDefaults]objectForKey:@"tasks"];


 - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
    {

        NSLog(@"number of tasks when tableview:%d", self.TasksArray.count);
            //return self.TasksArray.count;
        return self.TasksArray.count;
    }

Answer 1

将对象设置为[NSUserDefaults standardUserDefaults]后请务必致电[NSUserDefaults standardUserDefaults] synchronize];

- (BOOL)textFieldShouldReturn:(UITextField *)textField{
    NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
    if (!self.tasks) self.tasks = [NSMutableArray new];

    [self.tasks addObject:textField.text];
    [userDefaults setObject:self.tasks forKey:@"tasks"];
    [userDefaults synchronize];
    NSLog(@"tasks:%@", [[NSUserDefaults standardUserDefaults]objectForKey:@"tasks"]);
    NSLog(@"number of tasks:%d", self.tasks.count); <-- this print works good, also the first one
    [textField addObserver:self forKeyPath:@"name" options:NSKeyValueObservingOptionNew context:NULL];
    [textField resignFirstResponder];
    return YES;
}

在您将对象从[self.tableView reloadData]分配到[NSUserDefaults standardUserDefaults]后，您可能还需要致电self.TasksArray。

- (void)viewDidLoad
{
  [super viewDidload];

  if (!self.TasksArray) self.TasksArray = [NSMutableArray new];
  self.TasksArray = [[NSUserDefaults standardUserDefaults]objectForKey:@"tasks"];

  [self.tableView reloadData]; 
}   

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
  NSLog(@"number of tasks when tableview:%d", self.TasksArray.count);
  return self.TasksArray.count;
}

根据您的应用架构，最好在[self.tableView reloadData]

中拨打viewWillAppear:(BOOL)animated

Answer 2

尝试使用textFieldDidEditing下面的代码。

- (void)textFieldDidEndEditing:(UITextField *)textField
{
   NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
    if (!self.tasks) self.tasks = [NSMutableArray new];

    [self.tasks addObject:textField.text];
    [userDefaults setObject:self.tasks forKey:@"tasks"];
    [userDefaults synchronize];
    NSLog(@"tasks:%@", [[NSUserDefaults standardUserDefaults]objectForKey:@"tasks"]);
    NSLog(@"number of tasks:%d", self.tasks.count); <-- this print works good, also the first one
    [textField addObserver:self forKeyPath:@"name" options:NSKeyValueObservingOptionNew context:NULL];

    [textField resignFirstResponder];
    [self.yourtableview reloadData];

}

希望它可以帮助你..

如何使用MutableArray信息制作KVO观察者并提供tableview？

2 个答案: