将 NSMutableDictionary 从一个视图传递到另一个视图

Question

我正在尝试将数据从一个 ViewController 传递到另一个 ViewController。

Firstviewcontroller.m

-(void)NavigateToAnotherScreen:(NSMutableDictionary*)dict{
    [self performSegueWithIdentifier:@"NavDashBoardToInfo" sender:self];

}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([[segue identifier] isEqualToString:@"NavDashBoardToInfo"])
    {
        InfoViewController *vc = [segue destinationViewController];
        [vc setAppointmentDictionary:dict];
    }
}

Secondviewcontroller.h

@property (strong, nonatomic) NSMutableDictionary *AppointmentDictionary;

Secondviewcontroller.m

@synthesize AppointmentDictionary;

- (void)viewWillAppear:(BOOL)animated{
    NSLog(@"dict===>%@",AppointmentDictionary); // This gives me null
}

请帮助我。我做错了什么。

我在 viewwillappear 中得到 AppointmentDictionary = (null)。虽然我正在做这个的正确副本。

Answer 1

您正在创建 InfoViewController 实例，而不是推送该视图控制器。您在此处执行 "performSegueWithIdentifier" 将创建新实例，因此您的第一个实例 "info" 不会通过此处。你可以用其他方式做。

 InfoViewController *info = [[InfoViewController alloc] init];
 info.AppointmentDictionary = [dict mutableCopy];
 [self.navigationController pushViewController: info animated:true];

选项 2：

-(void)NavigateToAnotherScreen:(NSMutableDictionary*)dict{
    [self performSegueWithIdentifier:@"NavDashBoardToInfo" sender: [dict mutableCopy]];

}
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    if ([segue.identifier isEqualToString:@"NavDashBoardToInfo"]) {
        InfoViewController *viewController = (InfoViewController *)segue.destinationViewController;
        viewController.AppointmentDictionary = (NSMutableDictionary *)sender;
    }
}

在 prepareforsegue 方法中，您必须像上面提到的那样传递值。注意：确保你的目标视图控制器是 InfoViewController

Answer 2

试试这个：

-(void)NavigateToAnotherScreen:(NSMutableDictionary*)dict
{
    [self performSegueWithIdentifier:@"NavDashBoardToInfo" sender:dict];
}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
         InfoViewController *info = segue.destinationViewController;
         info.AppointmentDictionary = sender;
}

Answer 3

如果您使用 performsegue 进行导航，那么您可以使用以下方法在 ViewControllers

之间传输数据

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([[segue identifier] isEqualToString:@"NavDashBoardToInfo"])
    {
        InfoViewController *info = [segue destinationViewController];
        info.AppointmentDictionary = "Value you want to pass";
    }
}

Answer 4

试试这个

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if ([segue.destinationViewController respondsToSelector:@selector(setAppointmentDictionary:)]) {
    [segue.destinationViewController performSelector:@selector(setAppointmentDictionary:)
                                          withObject:dict];
}
}

Answer 5

如果您使用的是 performSegueWithIdentifier，请在函数中提供正文。不要使用代码创建任何新实例并在故事板中提供 segue -

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    if ([segue.identifier isEqualToString:@"YourController_Segue"]) {
        YourController *viewController = (YourController *)segue.destinationViewController;
        viewController.AppointmentDictionary = (NSMutableDictionary *)sender;
    }
}

将 NSMutableDictionary 从一个视图传递到另一个视图

Pass NSMutableDictionary from one view to another

copy

objective-c

nsmutabledictionary

ios