Question

我已经看到了与此主题相关的其他帖子，但我无法解读与我遇到的问题相关的问题。我的项目的目标是有3个表视图，1个根，然后在根中选择一个项后推送到堆栈的第二个，然后在第二个视图中选择一个项后第三个推到堆栈。

我试图通过以编程方式使用名为FirstView的根创建导航控制器来实现此目的。然后在FirstView xib中包含第二个视图控制器，将SecondView推送到堆栈。然后在SecondView中使用第三个视图控制器将ThirdView推送到堆栈。

结果是我得到FirstView以显示并正确地将SecondView推送到堆栈。然后，当我在SecondView表中选择一个项目时，在尝试将ThirdView推送到堆栈时出现以下错误：“应用程序试图在目标上推送一个nil视图控制器。”

我将控制器连接到第二和第三控制器的插座，所以我不确定这两者之间的差异以及为什么第三个控制器为零。附上以下代码以获取推送视图的所有引用（对不起，如果这很多）

TestAppDelegate.h

#import <UIKit/UIKit.h>

@class RootViewController;

@interface TestAppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UINavigationController *navigationController;
@property (strong, nonatomic) UIWindow *window;

@end

TestAppDelegate.m

#import "FirstView.h"
#import "TestAppDelegate.h"

@implementation TestAppDelegate

@synthesize window = _window;
@synthesize navigationController;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    UIViewController *rootController = [[FirstView alloc] initWithNibName:@"FirstView" bundle:nil];

    navigationController = [[UINavigationController alloc] initWithRootViewController:rootController];

    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    [self.window addSubview:navigationController.view];
    [self.window makeKeyAndVisible];
    return YES;
}

FirstView.h

#import <UIKit/UIKit.h>

@class SecondView;

@interface FirstView : UITableViewController

@property (nonatomic, strong) NSMutableArray *mList;
@property (nonatomic, strong) IBOutlet SecondView *secondController;

@end

FirstView.m

#import "FirstView.h"
#import "SecondView.h"
#import "TestAppDelegate.h"

@implementation FirstView
@synthesize mList;
@synthesize secondController;

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{    
    [self.navigationController pushViewController:self.secondController animated:YES];
}

SecondView.h

#import <UIKit/UIKit.h>

@class ThirdView;

@interface SecondView : UITableViewController

@property (nonatomic, strong) NSMutableArray *secondList;
@property (nonatomic, strong) IBOutlet ThirdView *thirdController;

@end

SecondView.m

#import "ThirdView.h"
#import "SecondView.h"
#import "FirstView.h"
#import "TestAppDelegate.h"

@implementation SecondView
@synthesize secondList;
@synthesize thirdController;

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    [self.navigationController pushViewController:self.thirdController animated:YES];
}

在目标上推nil viewcontroller

0 个答案: