设置文本字段文本无效

我有一个屏幕,用户可以将电子邮件输入文本字段。其想法是,如果在输入电子邮件时,如果它尚未在存储的电子邮件中,它将提示用户将新的电子邮件/联系人输入到存储中。由于我在弹出联系人创建屏幕之前检查电子邮件是否有效,因此我希望将输入的文本直接放入新联系人创建页面的“电子邮件”字段中,并且不允许编辑。我尝试了许多方法,但无法让电子邮件显示在文本字段中。有人能解释为什么会这样吗?

用户输入电子邮件的初始VC代码。如果商店中不存在该电子邮件,则会触发创建联系人创建者页面的代码:

//I created this custom initializer since setting the text field (as I did below) would not work
ContactCreationViewController *contactCreationVC = [[ContactCreationViewController alloc] initWithEmail:trimmedText];
contactCreationVC.delegate = self;

//initially I tried setting the text here but it did not work, I now understand why
//[contactCreationVC.emailField setText:@"asdsadasd"];

[contactCreationVC setModalTransitionStyle:UIModalTransitionStyleCrossDissolve];
[contactCreationVC setModalPresentationStyle:UIModalPresentationOverCurrentContext];

[self presentViewController:contactCreationVC animated:YES completion:nil];

这是实际ContactCreatorVC的代码:

-(instancetype) initWithEmail:(NSString*)email{
    self = [super init];

    //tried setting email here which works as I check with breakpoints
    [self setEmail:email];

    //self.email = email here when I check
    return self;
}

....

- (nonnull UITableViewCell *)tableView:(nonnull UITableView *)tableView cellForRowAtIndexPath:(nonnull NSIndexPath *)indexPath {
switch (indexPath.row) {

....

    case 3: {
        ContactCreationTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:contactCreationCellIdentifier];
        cell.titleLabel.text = @"E-Mail";
        cell.userEntryTextfield.tag = 3;
        cell.userEntryTextfield.delegate = self;
        cell.userEntryTextfield.keyboardType = UIKeyboardTypeEmailAddress;

//I try setting the email here but self.email = nil (don't understand why)
        cell.userEntryTextfield.text = [NSString stringWithFormat:@"%@", self.email];
        cell.userEntryTextfield.userInteractionEnabled = NO;
        cell.userEntryTextfield.autocapitalizationType = UITextAutocapitalizationTypeNone;
        self.emailField = cell.userEntryTextfield;
        return cell;
    }

.....

}

即使问这么简单的问题,我也觉得自己很愚蠢,但我显然不明白幕后发生了什么,因为我什么都试过了。有人能解释发生了什么,并从最佳实践的角度提出理想的解决方案吗?

编辑:我想我的问题可以更简洁。。。这基本上可以归结为:为什么当我设定自我。当我访问self时,init中的电子邮件不会粘住。用cellForRow方法发送电子邮件(变为零)?

(textfield位于tableview的单元格中)