点击 View 空白释放键盘

 在view上添加一个UITapGestureRecognizer
- (void)viewDidLoad
{
[super viewDidLoad];
UITapGestureRecognizer *tapGr = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(viewTapped:)];
tapGr.cancelsTouchesInView = NO;
[self.view addGestureRecognizer:tapGr];
}
-(void)viewTapped:(UITapGestureRecognizer*)tapGr{
[activitySearchBar resignFirstResponder];
}