Question

我想创建一个按钮，将我带到另一个视图控制器并自动从3开始倒计时到0，但我不知道如何设置其他视图控制器的倒计时。这是我试过的代码：

@implementation TestViewController

-(IBAction)test:(id)sender {
    CountdownViewController *cdvc = [[CountdownViewController alloc]  
initWithNibName:@"CountViewController" bundle:nil];
    [self.navigationController pushViewController:cdvc animated:YES];
}

@implementation CountdownViewController

int maintInt = 3;
NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(countDown) userInfo:nil repeats:YES];

-(void)countDown {
    maintInt -= 1;
    count.text = [NSString stringWithFormat:@"%i", maintInt];
    if(maintInt==1){
        [timer invalidate];
    }
}

Answer 1

您必须将倒计时代码放在一个方法中，您应该使用viewDidLoad或viewWillAppear方法调用该方法。

@implementation TestViewController

-(IBAction)test:(id)sender {
    CountdownViewController *cdvc = [[CountdownViewController alloc]  
initWithNibName:@"CountViewController" bundle:nil];
    [self.navigationController pushViewController:cdvc animated:YES];
}

@end

@implementation CountdownViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    // .. customize your views here ..

    // Initialize the timer once your view has been loaded.
    //
    NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(countDown:) userInfo:nil repeats:YES];
}


static int maintInt = 3;

- (void)countDown:(NSTimer *)timer {
    count.text = [NSString stringWithFormat:@"%i", maintInt];
    maintInt -= 1;

    if (maintInt == 0 && timer) {
        [timer invalidate];
        timer = nil;
    }
}

@end

自动启动倒计时Xcode XIB

1 个答案: