Hello Devs(这是我在Stack-Overflow中的第一篇文章,所以请在评论中告诉我我做错了:).
UIPinchGestureRecognizer *twoFingerPinch = [[[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingerPinch:)] autorelease]; [[self view] addGestureRecognizer:twoFingerPinch];
虚空行动：
- (void)twoFingerPinch:(UIPinchGestureRecognizer *)recognizer
{
NSLog(@"Pinch scale: %f",recognizer.scale);
}
问题是我想检测用户是否在20秒内没有收缩,因此我可以提醒用户@“捏合以显示更多图像”.我正在使用图像缩略图,如果用户捏它将显示更多图像.感谢您的帮助,祝您度过愉快的假期.
解决方法
使用20秒启动计时器,当用户捏时,仅在twoFingerPinch方法中无效.无论何时需要开始检查,都要启动此计时器.在计时器操作方法中,您可以输入代码以显示此警报.
在.h文件中声明计时器,
@property(nonatomic,strong) NSTimer *timer;
在viewDidLoad或你想要启动计时器检查这个的任何方法,
self.timer = [NSTimer scheduledTimerWithTimeInterval:20.0f target:self selector:@selector(showAlert) userInfo:nil repeats:YES];
在showAlert方法中,
- (void)showAlert {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:nil message:@"Pinch to show more Images" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"OK",nil];
[alert show];
}
在twoFingerPinch方法中,
- (void)twoFingerPinch:(UIPinchGestureRecognizer *)recognizer
{
NSLog(@"Pinch scale: %f",recognizer.scale);
[self.timer invalidate];
//if the timer needs to be restarted add,self.timer = [NSTimer scheduledTimerWithTimeInterval:20.0f target:self selector:@selector(showAlert) userInfo:nil repeats:YES];
}