我正在开发一个应用程序，但它是一个相当旧的应用程序。客户不想花太多时间，所以我正在寻找一个简单快速的解决方法来解决这个问题。

用户必须为他们的个人资料写一个摘要，所以他们需要很大的空间来写。整个应用程序是用 AlertController 弹出窗口构建的，所以我想用更大的多行 UITextField 替换单行 UITextField .

我该怎么做才能做到这一点？ 我目前添加了以下代码:

UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"" message:@"Enter your summary" preferredStyle:UIAlertControllerStyleAlert];
    [alert addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField) {
        textField.placeholder = @"Summary";
        textField.autocapitalizationType = UITextAutocapitalizationTypeSentences;
        textField.text = _summaryLabel.text;

        NSLayoutConstraint *constraint = [NSLayoutConstraint constraintWithItem:textField attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1 constant: 110.0];
        [textField addConstraint:constraint];
        [textField layoutIfNeeded];
    }];

这意味着 UITextField 实际上更大，但它不是多行的，而且它还在垂直居中文本。我该怎么办？

最佳答案

正如@rmaddy 所说，UITextField 仅适用于单行，您可以使用UITextView。

你可以这样实现:

How to use UITextView in UIAlertController

UIAlertController *alert = [UIAlertController
                            alertControllerWithTitle:@"Enter your summary"
                            message:@"\n\n\n\n\n\n\n\n"
                            preferredStyle:UIAlertControllerStyleAlert];
alert.view.autoresizesSubviews = YES;

UITextView *textView = [[UITextView alloc] initWithFrame:CGRectZero];
textView.translatesAutoresizingMaskIntoConstraints = NO;

NSLayoutConstraint *leadConstraint = [NSLayoutConstraint constraintWithItem:alert.view attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:textView attribute:NSLayoutAttributeLeading multiplier:1.0 constant:-8.0];
NSLayoutConstraint *trailConstraint = [NSLayoutConstraint constraintWithItem:alert.view attribute:NSLayoutAttributeTrailing relatedBy:NSLayoutRelationEqual toItem:textView attribute:NSLayoutAttributeTrailing multiplier:1.0 constant:8.0];

NSLayoutConstraint *topConstraint = [NSLayoutConstraint constraintWithItem:alert.view attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:textView attribute:NSLayoutAttributeTop multiplier:1.0 constant:-64.0];
NSLayoutConstraint *bottomConstraint = [NSLayoutConstraint constraintWithItem:alert.view attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:textView attribute:NSLayoutAttributeBottom multiplier:1.0 constant:64.0];
[alert.view addSubview:textView];
[NSLayoutConstraint activateConstraints:@[leadConstraint, trailConstraint, topConstraint, bottomConstraint]];

[alert addAction: [UIAlertAction actionWithTitle:@"Done"style:UIAlertActionStyleDefault handler:^(UIAlertAction*action) {
    NSLog(@"%@", textView.text);
}]];

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

或者使用UIAlertView:

How to Insert the UITextView into UIAlertview in iOS

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@""
                                                    message:@"Enter your summary"
                                                   delegate:self
                                          cancelButtonTitle:@"Cancel"
                                          otherButtonTitles:@"Done", nil];

UITextView *textView = [[UITextView alloc] initWithFrame:CGRectZero];
[alert setValue:textView forKey:@"accessoryView"];
[alert show];

或自定义您自己的警报，如 ios-custom-alertview

关于带有多行 UITextField 的 iOS AlertController，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/43591106/