当点击背景的时候出发事件，或者跳转界面或者产生其他的响应

-(void)viewDidLoad

{

UIImageView * imageView  = [UIImageView alloc]initWithFrame:CGRectmake

(20,20,200,100)]  ;

imageView.image = [UIImage imageName:@"aa.png"];

imageView.userInterationEnable = YES;

//主要的事应用这个类的方法

UITapGesturRecognizer * TapGesturRecognizer = [UITapGestureRecognizer alloc]

initWithTarget:self         action:@selecter(tapGestureRecognizer);

[imageView addGestureRecognizer:TapGesturRecognizer ];

[self.view addSubview:imageView];

}

//点击图片时，释放掉textfile的键盘

-(void)tapGestureRecognizer

{

[self.textfile resignFirstRsponder];

}