Ios 在应用程序启动时运行问题生成方法

我正在开发一个应用程序，将摄像头用于各种不同的用途。现在，当我启动应用程序时，我正在努力获取一些要运行的代码：

UIImagePickerController *imageView = [[UIImagePickerController alloc]init];
imageView.delegate = self;
imageView.sourceType = UIImagePickerControllerSourceTypeCamera;
imageView.showsCameraControls = NO;

[self presentViewController:imageView animated:YES completion:NULL];

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

}

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

- (void)applicationDidBecomeActive
{

    UIImagePickerController *imageView = [[UIImagePickerController alloc]init];
    imageView.delegate = self;
    imageView.sourceType = UIImagePickerControllerSourceTypeCamera;
    imageView.showsCameraControls = NO;

    [self presentViewController:imageView animated:YES completion:NULL];


}

@end

我需要在启动时在

imageView

UIView对象上执行此操作，这样当应用程序打开时，它会直接转到

UIImagePickerController

。以下是我的所有应用程序代码：

UIImagePickerController *imageView = [[UIImagePickerController alloc]init];
imageView.delegate = self;
imageView.sourceType = UIImagePickerControllerSourceTypeCamera;
imageView.showsCameraControls = NO;

[self presentViewController:imageView animated:YES completion:NULL];

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

}

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

- (void)applicationDidBecomeActive
{

    UIImagePickerController *imageView = [[UIImagePickerController alloc]init];
    imageView.delegate = self;
    imageView.sourceType = UIImagePickerControllerSourceTypeCamera;
    imageView.showsCameraControls = NO;

    [self presentViewController:imageView animated:YES completion:NULL];


}

@end

---

如果要在启动应用程序时运行代码，应将其放入：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

如果希望UIImagePickerController成为第一个显示的viewController，则应将其设置为窗口的rootViewController，如下所示：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Set up imageView here

    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    [self.window makeKeyAndVisible];
    self.window.rootViewController = imageView;
    return YES;
}

---

如果/当您想从屏幕上已显示的另一个viewController显示它时，请使用presentViewController。

如果您想在任何控制器中获得通知，您应该收听

UIApplicationIDBecMeactiveNotification

或

注销

[[NSNotificationCenter defaultCenter] removeObserver:self 
                                                name:UIApplicationDidBecomeActiveNotification
                                              object:nil];

在

dealloc

中或当您不想再收到通知时

---

如果你使用故事板，你的应用程序代理应该是这样的

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.
    return YES;
}

//…

@end 

如果您不使用故事板，您的应用程序代理可能会

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{    
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    [self.window makeKeyAndVisible];
    self.window.rootViewController = [[ViewController alloc] init];
    return YES;
}

//…

@end 

和视图控制器

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(applicationDidBecomeActive)
                                                 name:UIApplicationDidBecomeActiveNotification
                                               object:nil];
}

-(void)dealloc
{
    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name:UIApplicationDidBecomeActiveNotification
                                                  object:nil];
}

- (void)applicationDidBecomeActive
{

    UIImagePickerController *imageViewPickerController = [[UIImagePickerController alloc] init];
    imageViewPickerController.sourceType = UIImagePickerControllerSourceTypeCamera;
    [self presentViewController:imageViewPickerController
                       animated:NO
                     completion:NULL];
}

@end

---

实际的问题是什么？你发布的代码在哪里？我编辑了我的帖子，希望它更清晰一点。谢谢你的评论。我觉得这让我非常接近，但我不太明白UIWindow对象是什么。我给了它一个谷歌，我找不到任何简明的信息。我不太理解viewController和UIWindow之间的区别。一个应用程序有一个窗口，但可以有多个viewController。在Xcode中创建项目时，它应该在AppDelegate.m文件中包含didFinishLaunchingWithOptions中的窗口代码。您只需添加rootViewController的行设置。您可能应该阅读一些文档：请观看WWDC 2011视频“实现UIViewController包容”。它解释了一点，为什么这样更改rootviewcontroller是个坏主意，实际上工程师多次警告“我向您保证，坏事情会发生”。最不可能发生的事情是方向问题。@vikingosegundo是的，他的答案可能不是这个问题的最佳答案，但我假设你认为设置rootViewController是不对的。我想我应该更清楚一些。我真的需要在应用程序打开时显示我的

UIImagePickerController

，我希望使用故事板让UI设计更简单一点。我知道按钮和其他UI元素可以通过编程方式创建，但对于这个摄像头应用程序，视觉布局更可取。那么，我可以将代码应用到这个应用程序吗？我看不出这如何使我能够启动

UIImagePickerController

。您没有看到在收到通知

UIApplicationIDBecMeactivification

时执行您的

ApplicationIDBecMeactivitive

吗？啊，是的。因此，我将代码放在AppDelegate.m中的

applicationIDBecomeActive

中？这样，当运行

UIApplicationIDBECOMEACTIVENTIfication

时，它会引用这个？