Question

计时器不会停止，不会停在stopButtonPressed中，如果sec值为0则不会停止。计时器应该例如计数从100到0.如果值== 0或按下停止按钮，计时器应该停止！但它仍在继续计算。

我的错误在哪里？我尝试了不同的方法但没有任何作用。

以下是代码：

<。>文件中的

@property (weak, nonatomic) NSTimer *countdownTimer;

<。>文件中的

- (void)timer {

    sec = sec - 1;
    int minutes = sec / 60;
    int seconds = sec - (minutes * 60);

    [_timerLabel setText:[NSString stringWithFormat:@"%02d:%02d",minutes,seconds]];

    if (sec == 0) {
        [_countdownTimer invalidate];
        _countdownTimer = nil;
    }
}

- (void)startTimer {

    _countdownTimer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(timer) userInfo:nil repeats:YES];
}

- (IBAction)startButtonPressed:(id)sender {

    [self startTimer];
    [_startButton setHidden:YES];
    [_stopButton setHidden:NO];
}

- (IBAction)stopButtonPressed:(id)sender {

    [_stopButton setHidden:YES];
    [_countdownTimer invalidate];
    [_startButton setHidden:NO];
}

谢谢！

Answer 1

我已经尝试过这段代码而且效果很好，当你按下stopButton并且sec == 0时，计时器停止;

#import "ViewController.h"

@interface ViewController (){
    NSTimer*_countdownTimer;
    int sec;
}

@property (nonatomic,weak) IBOutlet UILabel*_timerLabel;
@property (nonatomic,weak) IBOutlet UIButton*_startButton;
@property (nonatomic,weak) IBOutlet UIButton*_stopButton;

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    sec=100;
}

- (void)timer {

    sec = sec - 1;
    int minutes = sec / 60;
    int seconds = sec - (minutes * 60);

    [self._timerLabel setText:[NSString stringWithFormat:@"%02d:%02d",minutes,seconds]];

    if (sec == 0) {
        [_countdownTimer invalidate];
        _countdownTimer = nil;
    }
}

- (void)startTimer {
    _countdownTimer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(timer) userInfo:nil repeats:YES];
}

- (IBAction)startButtonPressed:(id)sender {
    [self startTimer];
    [self._startButton setHidden:YES];
    [self._stopButton setHidden:NO];
}

- (IBAction)stopButtonPressed:(id)sender {
    [self._stopButton setHidden:YES];
    [_countdownTimer invalidate];
    _countdownTimer=nil;
    [self._startButton setHidden:NO];
}

NSTimer [计时器无效]不起作用

1 个答案: