iOS获取用户名和当前时间

Question

我正在开发一个 iOS 应用程序，它的一个屏幕应该显示当前的用户名和时间，但我在尝试将该信息分配到 NSStrings 时遇到了麻烦:当我运行该应用程序时，标签显示(空)消息。

这是我的代码:

About.h

@interface About : UIViewController

@property (weak) IBOutlet UILabel * username;
@property (weak) IBOutlet UILabel * date;

@property (strong, nonatomic) NSString * usuari;
@property (strong, nonatomic) NSString * data;
@property (strong, nonatomic) NSString * name;
@property (strong, nonatomic) NSString * currentTime;


@end

About.m

#import "About.h"

@interface About()
@end

@implementation About

- (void)viewDidLoad
{
    [super viewDidLoad];

    UILabel * username = [[UILabel alloc] initWithFrame:CGRectMake(162, 106, 150, 72)];
    [self.view addSubview: username];
    username.numberOfLines = 4;
    username.textColor = [UIColor blackColor];
    username.text = [NSString stringWithFormat:@"Usuari: %@", _usuari];

    UILabel * date = [[UILabel alloc] initWithFrame:CGRectMake(160, 261, 1488, 44)];
    [self.view addSubview: date];
    date.numberOfLines = 4;
    date.textColor = [UIColor blackColor];
    date.text = [NSString stringWithFormat:@"Hora: %@", _currentTime];

}

-(void) gettingUser
{
    [[UIDevice currentDevice] name];
   _username.text = [NSString stringWithFormat:@"Usuari: %@", _name];
}

-(void) gettingTime
{
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateStyle:NSDateFormatterMediumStyle];
    [dateFormatter setTimeStyle:NSDateFormatterMediumStyle];
    [dateFormatter setTimeZone:[NSTimeZone localTimeZone]];
    NSString *currentTime = [dateFormatter stringFromDate:[NSDate date]];

    _date.text = [NSString stringWithFormat:@"Hora: %@", _currentTime];
    //self.date.text = [NSDate date];

    //NSTimer schedule interval
    //NSDateFormatter alloc
}


@end

你能帮我解决这个问题吗？

Answer 1

在引用对象的属性而不是属性的底层 ivar 时使用“self.”。

例如像这样更改一行:

_username.text = [NSString stringWithFormat:@"Usuari: %@", _name];

到

self.username.text = [NSString stringWithFormat:@"Usuari: %@", self.name];