键盘点出来就退不掉了，你可以把这几句加到有键盘的控制器里

//在view里添加一个点击事件
UITapGestureRecognizer *tapGr = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(viewTapped:)];
tapGr.cancelsTouchesInView = NO;
[self.view addGestureRecognizer:tapGr];

//点击空白处退出键盘
-(void)viewTapped:(UITapGestureRecognizer*)tapGr
{
[field resignFirstResponder];
}

//点击return 时调用的代理方法在这里退出键盘并完成搜索功能
-(BOOL)textFieldShouldReturn:(UITextField *)textField
{

[textField resignFirstResponder];

return YES;
}