长按手势操作只有刚开始的时候执行的是UIGestureRecognizerStateBegan事件，其他均为end手势，因此可以判断手势事件做相应的操作，如长按保存图片等。
//6.添加长按手势
UILongPressGestureRecognizer *gesture=[[UILongPressGestureRecognizer alloc]initWithTarget:self action:@selector(handleLongPressGestures:)];
gesture.minimumPressDuration=1.0f;
gesture.numberOfTouchesRequired = 1;
gesture.delegate = self;
self.qrCodeImage.userInteractionEnabled=YES;
[self.qrCodeImage addGestureRecognizer:gesture];
- (void) handleLongPressGestures:(UILongPressGestureRecognizer *)paramSender{
if (paramSender.state == UIGestureRecognizerStateBegan) {
[self savePhoto];
NSLog(@"long pressTap state :begin");
}else {
NSLog(@"long pressTap state :end");
}
NSLog(@"-------------");
}
