对于某些有互相关联的手势，如单击与双击，轻扫与长移可能会存在冲突，这时可以使用 requireGestureRecognizerToFail 方法。
UITapGestureRecognizer *tapGR =[[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(handleTap:)]; [tapGR setDelegate:self]; [tapGR setNumberOfTapsRequired:1]; [self addGestureRecognizer:tapGR]; UITapGestureRecognizer *doubleTapGR = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(handleDoubleTap:)]; [doubleTapGR setNumberOfTapsRequired:2]; [self addGestureRecognizer:doubleTapGR]; [tapGR requireGestureRecognizerToFail : doubleTapGR];