ios - SpriteKit 中的更新方法不能正确更新时间

Question

如果我在更新方法中实现该方法，我想以秒为单位，它只在第一秒有效，然后它会不停地打印数字，而不会在打印下一个数字之前等待一秒钟；我不明白为什么会这样

 -(void) countinSeconds{
            SKAction *count = [SKAction waitForDuration:1];

            SKAction *time = [SKAction runBlock:^{
                    timex++;
                       }];
            SKAction *print = [SKAction runBlock:^{
            NSLog(@"%i",timex);
            }];
            [self runAction:[SKAction sequence:@[count,time,print]]];



        }
        -(void)update:(NSTimeInterval)currentTime {

                    [self countinSeconds];

        }

Answer 1

不需要为此使用操作； update: 方法是通过当前时间传递的，所以只需记住您何时开始并做一些简单的数学运算即可:

@implementation YourClass () {
    BOOL _started;
    NSTimeInterval _startTime;
    NSUInteger _lastLogTime;
}
@end

@implementation YourClass

- (void)update:(NSTimeInterval)currentTime
{
    if (!_started) {
        _startTime = currentTime;
        _started = YES;
    } else {
        NSUInteger elapsedTime = (NSUInteger)(currentTime - _startTime);
        if (elapsedTime != _lastLogTime) {
            NSLog(@"Tick: %lu", elapsedTime);
            _lastLogTime = elapsedTime;
        }
    }
}

@end