UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] init];

// 连续敲击2次

tap.numberOfTapsRequired = 2;

// 需要2根手指一起敲击

tap.numberOfTouchesRequired = 2;

[self.iconView addGestureRecognizer:tap];

[tap addTarget:self action:@selector(tapIconView:)];

手势识别的状态

typedef NS_ENUM(NSInteger, UIGestureRecognizerState) {

    // 没有触摸事件发生，所有手势识别的默认状态

    UIGestureRecognizerStatePossible,

    // 一个手势已经开始但尚未改变或者完成时

    UIGestureRecognizerStateBegan,

    // 手势状态改变

    UIGestureRecognizerStateChanged,

    // 手势完成

    UIGestureRecognizerStateEnded,

    // 手势取消，恢复至Possible状态

    UIGestureRecognizerStateCancelled,

    // 手势失败，恢复至Possible状态

    UIGestureRecognizerStateFailed,

    // 识别到手势识别

    UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded

};