ios - 应用程序试图在目标上推送一个 nil View Controller

Question

我正在创建一个没有 Storyboard的应用程序，当用户单击表格 View 单元格时，我无法从该单元格的详细 View 移动。

在我创建和处理 TableView 的类中，我有以下代码:

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    PersonDetailViewController *detailViewController;
    Person *person = [self.playerArray objectAtIndex:indexPath.row];
    detailViewController.person = person;
    [[self navigationController] pushViewController:detailViewController animated:YES];

}

所以我试图将详细信息 View Controller 推送到屏幕上，然后在该详细信息屏幕上显示用户信息。我试图找到解决方案，但我遇到的大多数答案都使用 Storyboard，而我没有使用 Storyboard。

在我的 PersonDetailViewController.m 类中，我有以下代码:

#import "PersonDetailViewController.h"

@interface PersonDetailViewController ()

@end

@implementation PersonDetailViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.personInfo = [[UITextField alloc] initWithFrame:CGRectMake(45, 30, 200, 40)];
    _personInfo.backgroundColor = [UIColor whiteColor];


}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

@end

我不确定这是否是问题的原因，但在我的代表中我有以下内容:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    self.window.backgroundColor = [UIColor whiteColor];
    self.tableViewController = [[TableViewController alloc]init];
    UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:self.tableViewController];
    self.window.rootViewController = nav;
    [self.window makeKeyAndVisible];
    return YES;
}

我当时在想，这可能与创建导航 Controller 有关，但我一直在研究它，但我认为这与创建导航 Controller 无关。

Answer 1

您错过了 tableView:didSelectRowAtIndexPath: 方法中 View Controller 的初始化

PersonDetailViewController *detailViewController = [[PersonDetailViewController alloc] init]; // or initWith...