UIAlertController是使用UIAlertAction的专用控制器。
值得注意的是苹果的docs：

重要

UIAlertController类旨在按原样使用，不支持子类化。此类的视图层次结构是私有的，不得修改。
虽然您可能没有对它进行子类化（您没有提供AlertHelper代码），但显然没有“按原样”使用它。
相反，您可能希望设计自己的“模拟”警报控制器。
这里有一个简单的例子...

AlertHelper.h

#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface AlertHelper : NSObject

+ (UIAlertController *)createAlertWithTitle:(NSString *)title
                                    message:(NSString *)message
                               cancelButton:(NSString *)cancel
                         continueButtonText:(NSString *)ok
                             continueAction:(UIAction *)continueAction
                               cancelAction:(UIAction *)cancelAction;

@end

NS_ASSUME_NONNULL_END

字符串

AlertHelper.m

#import "AlertHelper.h"

@implementation AlertHelper

+ (UIViewController *)createAlertWithTitle:(NSString *)title
                                    message:(NSString *)message
                               cancelButton:(NSString *)cancel
                         continueButtonText:(NSString *)ok
                             continueAction:(UIAction *)continueAction
                               cancelAction:(UIAction *)cancelAction;
{
    UIViewController *vc = [UIViewController new];
    vc.view.backgroundColor = [UIColor colorWithWhite:0.0 alpha:0.25];
    
    UIView *bkg = [UIView new];
    bkg.clipsToBounds = YES;
    bkg.backgroundColor = [UIColor systemBackgroundColor];
    bkg.layer.cornerRadius = 12.0;
    
    UILabel *titleLabel = [UILabel new];
    titleLabel.font = [UIFont systemFontOfSize:17.0 weight:UIFontWeightSemibold];
    titleLabel.numberOfLines = 0;
    titleLabel.textAlignment = NSTextAlignmentCenter;
    titleLabel.text = title;
    
    UILabel *msgLabel = [UILabel new];
    msgLabel.font = [UIFont systemFontOfSize:13.0 weight:UIFontWeightRegular];
    msgLabel.numberOfLines = 0;
    msgLabel.textAlignment = NSTextAlignmentCenter;
    msgLabel.text = message;

    UIButton *cancelButton = [UIButton systemButtonWithPrimaryAction:cancelAction];
    UIButton *okButton = [UIButton systemButtonWithPrimaryAction:continueAction];
    
    cancelButton.layer.borderColor = [UIColor systemBlueColor].CGColor;
    okButton.layer.borderColor = [UIColor systemBlueColor].CGColor;
    cancelButton.layer.borderWidth = 1.0;
    okButton.layer.borderWidth = 1.0;

    for (UIView *v in @[bkg, titleLabel, msgLabel, okButton, cancelButton]) {
        v.translatesAutoresizingMaskIntoConstraints = NO;
    }
    for (UIView *v in @[titleLabel, msgLabel, okButton, cancelButton]) {
        [bkg addSubview:v];
    }
    [vc.view addSubview:bkg];
    
    [NSLayoutConstraint activateConstraints:@[
        
        [titleLabel.topAnchor constraintEqualToAnchor:bkg.topAnchor constant:20.0],

        [titleLabel.leadingAnchor constraintEqualToAnchor:bkg.leadingAnchor constant:8.0],
        [titleLabel.trailingAnchor constraintEqualToAnchor:bkg.trailingAnchor constant:-8.0],
        
        [msgLabel.topAnchor constraintEqualToAnchor:titleLabel.bottomAnchor constant:4.0],
        [msgLabel.leadingAnchor constraintEqualToAnchor:bkg.leadingAnchor constant:8.0],
        [msgLabel.trailingAnchor constraintEqualToAnchor:bkg.trailingAnchor constant:-8.0],
        
        [cancelButton.topAnchor constraintEqualToAnchor:msgLabel.bottomAnchor constant:20.0],
        [cancelButton.leadingAnchor constraintEqualToAnchor:bkg.leadingAnchor constant:-1.0],

        [okButton.topAnchor constraintEqualToAnchor:cancelButton.topAnchor constant:0.0],
        [okButton.trailingAnchor constraintEqualToAnchor:bkg.trailingAnchor constant:1.0],

        [cancelButton.bottomAnchor constraintEqualToAnchor:bkg.bottomAnchor constant:1.0],
        
        [cancelButton.trailingAnchor constraintEqualToAnchor:okButton.leadingAnchor constant:1.0],
        [cancelButton.widthAnchor constraintEqualToAnchor:okButton.widthAnchor],

        [cancelButton.heightAnchor constraintEqualToConstant:40.0],
        [okButton.heightAnchor constraintEqualToAnchor:cancelButton.heightAnchor],
        
        [bkg.widthAnchor constraintEqualToConstant:274.0],
        [bkg.centerXAnchor constraintEqualToAnchor:vc.view.centerXAnchor],
        [bkg.centerYAnchor constraintEqualToAnchor:vc.view.centerYAnchor],

    ]];

    return vc;
}

@end

型
以及一个示例视图控制器：

ViewController.h

import <UIKit/UIKit.h>

@interface ViewController：UIViewController @end

ViewController.m

#import "ViewController.h"
#import "AlertHelper.h"

@interface ViewController ()
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    self.view.backgroundColor = [UIColor systemYellowColor];

    UIAction *act = [UIAction actionWithTitle:@"Show Fake Alert VC" image:nil identifier:nil handler:^(UIAction * _Nonnull action) {
        [self showFakeAlertVC];
    }];

    UIButton *btn = [UIButton systemButtonWithPrimaryAction:act];
    btn.backgroundColor = [UIColor colorWithWhite:0.95 alpha:1.0];
    btn.translatesAutoresizingMaskIntoConstraints = NO;
    [self.view addSubview:btn];
    
    UILayoutGuide *g = self.view.safeAreaLayoutGuide;
    
    [NSLayoutConstraint activateConstraints:@[
        [btn.topAnchor constraintEqualToAnchor:g.topAnchor constant:60.0],
        [btn.leadingAnchor constraintEqualToAnchor:g.leadingAnchor constant:80.0],
        [btn.trailingAnchor constraintEqualToAnchor:g.trailingAnchor constant:-80.0],
    ]];
}

- (void)removeFakeAlertVC {
    UIViewController *vc;
    for (int i = 0; i < [self.childViewControllers count]; i++) {
        if ([self.childViewControllers[i].title isEqualToString:@"MyFakeAlertVC"]) {
            vc = self.childViewControllers[i];
            break;
        }
    }
    if (nil != vc) {
        [vc willMoveToParentViewController:nil];
        [vc.view removeFromSuperview];
        [vc removeFromParentViewController];
    }
}
- (void)showFakeAlertVC {
    
    UIAction *okAction = [UIAction actionWithTitle:@"Continue" image:nil identifier:nil handler:^(UIAction * _Nonnull action) {
        // do something because OK / Continue was tapped
        NSLog(@"OK tapped!");
        [self removeFakeAlertVC];
    }];
    UIAction *cancelAction = [UIAction actionWithTitle:@"Cancel" image:nil identifier:nil handler:^(UIAction * _Nonnull action) {
        // do something because Cancel was tapped
        NSLog(@"Cancel tapped!");
        [self removeFakeAlertVC];
    }];
    
    UIViewController *alert = [AlertHelper createAlertWithTitle:@"Some really long Title that we expect to wrap."
                                                        message:@"Some really long Message that we also expect to wrap."
                                                   cancelButton:@"Cancel Btn"
                                             continueButtonText:@"Continue Btn"
                                                 continueAction:okAction
                                                   cancelAction:cancelAction
    ];
    
    [self addChildViewController:alert];

    // we'll use this when we want to remove the
    //  view and child controller
    //  in case we have more than one child
    alert.title = @"MyFakeAlertVC";
    
    UIView *sv = self.view;
    UIView *v = alert.view;
    
    v.translatesAutoresizingMaskIntoConstraints = false;
    
    [sv addSubview:v];
    [alert didMoveToParentViewController:self];
    
    [NSLayoutConstraint activateConstraints:@[
        
        [v.topAnchor constraintEqualToAnchor:sv.topAnchor constant:0.0],
        [v.leadingAnchor constraintEqualToAnchor:sv.leadingAnchor constant:0.0],
        [v.trailingAnchor constraintEqualToAnchor:sv.trailingAnchor constant:0.0],
        [v.bottomAnchor constraintEqualToAnchor:sv.bottomAnchor constant:0.0],

    ]];
    
}

@end

型
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