Question

我想使用pushViewController，但我不能。我记得我可以在xcode3中使用这段代码。

这是IBAction按钮中的代码

-(IBAction)changtoCal:(id)sender
{
    NSLog(@"get in");
    UINavigationController *cal_nav = [[UINavigationController alloc] initWithNibName:@"calculator" bundle:nil];
    [self.navigationController pushViewController:cal_nav animated:YES];
}

它不推。为什么???你能告诉我怎么推它？

这是我的AppDelegate .H

@class ViewController;

@interface AppDelegate : UIResponder <UIApplicationDelegate>
{
    UINavigationController *navigationController;
}

@property (strong, nonatomic) UIWindow *window;

@property (strong, nonatomic) ViewController *viewController;

@property (strong, nonatomic) IBOutlet UINavigationController *navigationController;

@end

的.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.viewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];
    self.window.rootViewController = self.viewController;
    [_window addSubview:[navigationController view]];
    [self.window makeKeyAndVisible];
    return YES;
}

Answer 1

您应该在IBAction中创建自定义UIViewController的实例，而不是新的UINavigationController

// change UICalculatorViewController to your view controller
UICalculatorViewController *cal_nav = [[UICalculatorViewController alloc] initWithNibName:@"calculator" bundle:nil];
[self.navigationController pushViewController:cal_nav animated:YES];

Answer 2

我猜我UIViewController未正确嵌入UINavigationController。这意味着self.navigationController = nil。

我不知道XIB，但您可以通过执行以下操作来修复它：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.viewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];
    UINavigationController *navc = [[UINavigationController alloc] initWithRootViewController:self.viewController];
    self.window.rootViewController = navc;
    [_window addSubview:navc.view];
    [self.window makeKeyAndVisible];
    return YES;
}

为什么我不能将pushViewController与UIButton一起使用？

2 个答案: