由故事板设置覆盖的控制值

Question

我有一个自定义类型LVSBBSettingsViewController的VC用于用户设置。 VC由LVSMainViewController中的主菜单显示。主VC以编程方式设置VC中的控件值。但是，当出现设置视图时，控件全部恢复为故事板中分配给它们的值。

我正在使用委托关闭设置视图，并在关闭时将数据从设置VC传回主VC。但是我不认为这是导致问题的原因，因为即使我删除它也会发生同样的事情。

造成这种情况的原因是什么？我有一种感觉，我错过了一些非常简单的东西......

LVSBBSettingsViewController.h：

#import <UIKit/UIKit.h>

@class LVSBBSettingsViewController;

#pragma mark LVSBBSettingsViewController Delegate

@protocol LVSBBSettingsViewControllerDelegate <NSObject>

- (void)settingsViewControllerDidCancel:(LVSBBSettingsViewController *)controller;
- (void)settingsViewControllerDidSave:(LVSBBSettingsViewController *)controller;

@end

#pragma mark LVSBBSettingsViewController

@interface LVSBBSettingsViewController : UITableViewController

@property (nonatomic, weak) id <LVSBBSettingsViewControllerDelegate> delegate;

@property (weak, nonatomic) IBOutlet UISwitch *showBranchVarLabelsSwitch;
@property (weak, nonatomic) IBOutlet UISwitch *useAnimationSwitch;
@property (weak, nonatomic) IBOutlet UISwitch *showAllNodesSwitch;
@property (weak, nonatomic) IBOutlet UILabel *tempLabel;

- (IBAction)cancel:(id)sender;
- (IBAction)done:(id)sender;

@end

LVSBBSettingsViewController.m：

#import "LVSBBSettingsViewController.h"

@interface LVSBBSettingsViewController ()

@end

@implementation LVSBBSettingsViewController

// ... Xcode-generated stuff ...

- (IBAction)cancel:(id)sender
{
    [self.delegate settingsViewControllerDidCancel:self];
}

- (IBAction)done:(id)sender
{
    [self.delegate settingsViewControllerDidSave:self];
}

@end

LVSBBMainViewController.h：

#import <UIKit/UIKit.h>

#import "LVSBBSettingsViewController.h"

@interface LVSMainViewController : UIViewController <LVSBBSettingsViewControllerDelegate>

@end

LVSBBMainViewController.m：

#import "LVSMainViewController.h"
#import "LVSBBMasterViewController.h"

@interface LVSMainViewController ()

@end

@implementation LVSMainViewController
{
    LVSBBMasterViewController *bbmvc;
}

// ... 

- (void)viewDidLoad
{
    [super viewDidLoad];

    // Get main storyboard
    UIStoryboard *st = [UIStoryboard storyboardWithName:[[NSBundle mainBundle].infoDictionary objectForKey:@"UIMainStoryboardFile"] bundle:[NSBundle mainBundle]];

    // Instantiate bbmvc
    bbmvc = [st instantiateViewControllerWithIdentifier:@"BBMasterViewControllerStoryboard"];

    // Initialize settings
    bbmvc.showBranchVarLabels = YES;
    bbmvc.useAnimation = YES;
    bbmvc.showAllNodes =  NO;
}

...

#pragma mark LVSBBSettingsViewController Delegate

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"ShowSettings"])
    {
        // Get pointer to settings VC
        UINavigationController *navigationController = segue.destinationViewController;
        LVSBBSettingsViewController *settingsViewController = [navigationController viewControllers][0];

        // Set delegate
        settingsViewController.delegate = self;

        // Populate settings VC
        // (same problem occurs if I replace right-hand sides of next 3 lines with NO;)
        settingsViewController.showBranchVarLabelsSwitch.on = bbmvc.showBranchVarLabels;
        settingsViewController.useAnimationSwitch.on = bbmvc.useAnimation;
        settingsViewController.showAllNodesSwitch.on = bbmvc.showAllNodes;
        settingsViewController.tempLabel.text = @"HELLO";
    }
}

- (void)settingsViewControllerDidCancel:(LVSBBSettingsViewController *)controller
{
    [self dismissViewControllerAnimated:YES completion:nil];
}

- (void)settingsViewControllerDidSave:(LVSBBSettingsViewController *)controller
{
    // Set settings in bbmvc
    bbmvc.showBranchVarLabels = controller.showBranchVarLabelsSwitch.on;
    bbmvc.useAnimation = controller.useAnimationSwitch.on;
    bbmvc.showAllNodes = controller.showAllNodesSwitch.on;

    [self dismissViewControllerAnimated:YES completion:nil];
}


@end

更新：作为解决方法，我在LVSBBSettingsViewController中添加了与LVSMainViewController中的属性匹配的属性。在prepareForSegue:sender:中，我设置了这些属性，而不是直接设置控件。然后在viewDidLoad LVSBBSettingsViewController中，我根据属性设置控件值。这似乎有效。但仍然不确定为什么我不能直接设置控制值。