textField becomeFirstResponder failed

[HuanLiu]

I found that when current viewController show up again , the textField can't become first responder if return no in this method

- (BOOL)tokenFieldShouldEndEditing:(ZFTokenField *)textField
{
    return NO;
}

[HuanLiu]

finally , I changed below method, fixed this problem . I won't remove textField .

- (void)reloadFieldData
{
    for (UIView *view in self.tokenViews) {
        if ([view isKindOfClass:[ZFTokenTextField class]]) {
            continue;
        }
        [view removeFromSuperview];
    }
    self.tokenViews = [NSMutableArray array];
   ...
  if ( ![self.tokenViews containsObject:self.textField] ) {
        [self.tokenViews addObject:self.textField];
    }
    if ( ![self.textField isDescendantOfView:self] ) {
        [self addSubview:self.textField];
    }else{
        [self bringSubviewToFront:self.textField];
    }