[tap addtarget:self action:@selector(tapiconview:)];
3.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
};