'updateTimer'未声明（首次使用此功能）

Question

我收到此错误''updateTimer'未声明（首次在此函数中使用）'

这是代码：

#import <UIKit/UIKit.h>


@interface SleepAppFinalViewController : UIViewController
{

    //IBOutlet UILabel *myLabel;

    IBOutlet UILabel *_label;
    NSTimer *timer;

}

-(void)updateTimer;

的.m

@implementation SleepAppFinalViewController

-(void)updateTimer {

    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setDateFormat:@"hh:mm:ss"];
    _label.text = [formatter stringFromDate:[NSDate date]];
    [formatter release];
}

- (void)viewDidLoad
{
    timer = [NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:(updateTimer) userInfo:nil repeats:YES];
    [super viewDidLoad];


}

错误发生在'timer'

的viewdidload行上

Answer 1

应该是@selector(updateTimer)而不是(updateTimer)。

Answer 2

- (void)viewDidLoad
{
    timer = [NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:@selector(updateTimer) userInfo:nil repeats:YES];
    [super viewDidLoad];


}