触摸键盘外关闭键盘

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event

{

    for (UIView *view_ in [self.view subviews]) {

        if ([view_ isKindOfClass:[UITextField class]]) {

            UITextField *tf = (UITextField *)view_;

            [tf resignFirstResponder];

        }

    }

}