ios - 在 iOS 的 SWRevealController 中保持 View Controller 的保存状态？

我在我的应用程序中使用 SWRevealController。我有一个 MainController 作为“HOME”，它会在应用程序启动时显示。现在我在该屏幕上有 textfield 和其他控件。当我切换到另一个屏幕并返回“主页”时，“主页”屏幕上的所有数据都消失了。它没有显示任何数据。我想保存它的状态。现在我想将该 View Controller 保留在堆栈中，以便当我回到此 viewcontroller 时，它仍保留在堆栈中，而其他 View Controller 刚刚弹出。请解释我该怎么做？

我正在使用下面的代码。

-(void)tableViewUITableView *)tableView didSelectRowAtIndexPathNSIndexPath *)indexPath
{
    UITableViewCell *cell=[self.tableView cellForRowAtIndexPath:indexPath];
    if(indexPath.row==0)
    {
        [self performSegueWithIdentifier"home" sender:cell];
        [cell setSelected:YES];
    }

    else if(indexPath.row==1)
    {
        [self performSegueWithIdentifier"settings" sender:cell];
    }

    else if(indexPath.row==2)
    {
        [self performSegueWithIdentifier"help" sender:cell];
    }
    else if(indexPath.row==3)
    {
        [self performSegueWithIdentifier“about” sender:cell];
    }

}

- (void)prepareForSegueUIStoryboardSegue *)segue senderid)sender
{
    NSLog(@"Segue");
    NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow];
    UINavigationController *destViewController = (UINavigationController*)segue.destinationViewController;
    destViewController.title = [[titles objectAtIndex:indexPath.row] capitalizedString];
   if([segue.identifier isEqualToString"settings"])
    {
        self.revealViewController.navigationItem.title = @"settings";

    }
    else  if([segue.identifier isEqualToString"help"])
    {
        self.revealViewController.navigationItem.title = @"help";
    }
    else  if([segue.identifier isEqualToString"about"])
    {
        self.revealViewController.navigationItem.title = @"about";
    }

    if([segue isKindOfClass:[SWRevealViewControllerSegue class]])
    {
        SWRevealViewControllerSegue *swSegue = (SWRevealViewControllerSegue*) segue;

        swSegue.performBlock = ^(SWRevealViewControllerSegue* rvc_segue, UIViewController* svc, UIViewController* dvc) {
            UINavigationController* navController = (UINavigationController*)self.revealViewController.frontViewController;
            [navController setViewControllers: @[dvc] animated: NO ];
            [self.revealViewController setFrontViewPosition: FrontViewPositionLeft animated: YES];



        };

    }

  }

编辑:

它在下面的代码中尝试过，如果我在“主页”和其他屏幕之间切换两次，它就可以工作。

-(void)tableViewUITableView *)tableView didSelectRowAtIndexPathNSIndexPath *)indexPath
{
    UITableViewCell *cell=[self.tableView cellForRowAtIndexPath:indexPath];
    if(indexPath.row==0)
    {
        if(objMainController != nil)
        {
            UINavigationController* navController = (UINavigationController*)self.revealViewController.frontViewController;
            [navController setViewControllers: @[objMainController] animated: NO ];
            [self.revealViewController setFrontViewPosition: FrontViewPositionLeft animated: YES];
        }
        else
        {
            [self performSegueWithIdentifier"home" sender:cell];
            [cell setSelected:YES];
        }

    }
    else if(indexPath.row==1)
    {

        [self performSegueWithIdentifier"settings" sender:cell];
    }
    else if(indexPath.row==2)
    {

        [self performSegueWithIdentifier"help" sender:cell];
    }
    else if(indexPath.row==3)
    {

        [self performSegueWithIdentifier:@"about" sender:cell];
    }


}

准备继续

- (void)prepareForSegueUIStoryboardSegue *)segue senderid)sender
{
    NSLog(@"Segue");
    NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow];
    UINavigationController *destViewController = (UINavigationController*)segue.destinationViewController;
    destViewController.title = [[titles objectAtIndex:indexPath.row] capitalizedString];
   if([segue.identifier isEqualToString:@"settings"])
    {
        self.revealViewController.navigationItem.title = @"settings";

    }
    else  if([segue.identifier isEqualToString:@"about"])
    {
        self.revealViewController.navigationItem.title = @"about";
    }
    else  if([segue.identifier isEqualToString:@"help"])
    {
        self.revealViewController.navigationItem.title = @"help";
    }


    if([segue isKindOfClass:[SWRevealViewControllerSegue class]])
    {
        SWRevealViewControllerSegue *swSegue = (SWRevealViewControllerSegue*) segue;

        swSegue.performBlock = ^(SWRevealViewControllerSegue* rvc_segue, UIViewController* svc, UIViewController* dvc) {
            UINavigationController* navController = (UINavigationController*)self.revealViewController.frontViewController;
            if([segue.identifier isEqualToString:@"home"])
            {
                objMainController = (MainViewController*)destViewController;
                self.revealViewController.navigationItem.title = @"home";
                [navController setViewControllers: @[objMainController] animated: NO ];
            }
            else
            {
                [navController setViewControllers: @[dvc] animated: NO ];

            }

            [self.revealViewController setFrontViewPosition: FrontViewPositionLeft animated: YES];
        };

    }

  }

---

Best Answer-推荐答案

每次执行 segue 时，都会在 destinationViewController 内为您创建一个新的 UIViewController 实例，并且在创建后您需要保留对它的引用(首先时间)。

步骤#1

保留对您需要保存状态的所有 UIViewController 实例的引用-

SettingsViewController* objSettingsVC;

步骤 #2

如果您需要导航到的屏幕的实例之前已创建，请不要执行 segue-

- (void)tableViewUITableView *)tableView didSelectRowAtIndexPathNSIndexPath *)indexPath
{
    UITableViewCell* cell = [self.tableView cellForRowAtIndexPath:indexPath];

    if(indexPath.row == 1)
    {
        if(objSettingsVC != nil)
        {
            UINavigationController* navController = (UINavigationController*)self.revealViewController.frontViewController;
            [navController setViewControllers: @[objSettingsVC] animated: NO ];
            [self.revealViewController setFrontViewPosition: FrontViewPositionLeft animated: YES];
        }
        else
        {
            [self performSegueWithIdentifier:@"settings" sender:cell];
        }
    }
}

步骤#3

将 UIViewController 实例保存在变量中，以便稍后在 prepareForSegue: -

中第一次创建它时引用它

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    UINavigationController* destViewController = (UINavigationController*)segue.destinationViewController;

    if([segue.identifier isEqualToString:@"settings"])
    {
        objSettingsVC = (SettingsViewController*)destViewController;
        self.revealViewController.navigationItem.title = @"Settings";
    }
}

希望对你有帮助。

更新:

正如下面评论中所讨论的，您还需要将 initialViewController 实例保存在一个变量中。以下是你可以做到的。

AppDelegate.h

#import <UIKit/UIKit.h>
#import "ViewController.h"

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;
@property (strong, nonatomic) ViewController *objMainController;


@end

ViewController.m

#import "ViewController.h"
#import "AppDelegate.h"

@interface ViewController ()

@end

@implementation ViewController

-(void)viewDidLoad
 {
     [super viewDidLoad];

     AppDelegate* appDelegate = (AppDelegate*)[[UIApplication sharedApplication] delegate];
     appDelegate.objMainController = self;
 }


 @end

这不是一个很好的方法，但它会让你继续前进。你的 AppDelegate 不应该是所有这些导航逻辑的一部分，你应该把它保存在一个单独的对象中，负责你的应用程序导航。也许你的 SideTableViewController 在你的情况下。

关于ios - 在 iOS 的 SWRevealController 中保持 View Controller 的保存状态？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/37940017/