在 iOS 中将视图控制器的保存状态保存在 SWRevealController 中？

Question

我在我的 app.I 中使用 SWRevealController，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 "Home" 时，"Home" 屏幕上的所有数据都消失了。它不显示任何数据 there.I 想要保持其状态已保存。现在我想将该视图控制器保留在堆栈中，这样当我回到这个 viewcontroller 它仍然在堆栈中并且其他视图控制器只是弹出 out.Please 解释我该怎么做？

我为此使用以下代码。

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)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)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)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：

它尝试了下面的代码并且它正在工作，以防我在 "Home" 和其他屏幕之间切换两次。

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)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];
    }


}

准备中

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)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];
        };

    }

  }

Answer 1

每次执行 segue 时，都会在 destinationViewController 中为您创建一个新的 UIViewController 实例，您需要在创建后（第一次）保留对此实例的引用。

第 1 步

保留对您需要保存状态的所有 UIViewController 个实例的引用-

SettingsViewController* objSettingsVC;

第 2 步

如果您需要导航到的屏幕实例之前已创建，则不要执行 segue-

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)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];
        }
    }
}

第 3 步

将 UIViewController 实例保存在一个变量中，以便稍后在 prepareForSegue: -

中首次创建时引用它

- (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";
    }
}

希望对您有所帮助。

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。以下是您的操作方法。

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。您的 AppDelegate 不应该是所有这些导航逻辑的一部分，您应该将其保存在一个单独的对象中，负责您的应用程序导航。也许你的 SideTableViewController 在你的情况下。

在 iOS 中将视图控制器的保存状态保存在 SWRevealController 中？

keep saved state of view controller in SWRevealController in iOS?

iphone

objective-c

uinavigationcontroller

ios

swrevealviewcontroller

第 1 步

第 2 步

第 3 步

更新：

AppDelegate.h

ViewController.m