iphone - 单击按钮时 iOS 应用程序崩溃 iPhone

Question

我正在使用 xcode 4.2 和 ARC。下面是我正在使用的代码。当我点击任何按钮时，我的应用程序崩溃并突出显示 main.m 中的这段代码

有时我会收到这个错误

-[__NSCFTimer parentLogin:]: unrecognized selector sent to instance

有时应用程序会在没有任何错误的情况下崩溃。

return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));

我的代码是:

在我的 ViewController.m 中，我使用此代码访问 ChooseLogin View Controller 。

- (IBAction)action:(id)sender {


    ChooseLogin *loginScreen = [[ChooseLogin alloc] initWithNibName:@"ChooseLogin" bundle:nil];
    [UIView beginAnimations:@"flipview" context:nil];
    [UIView setAnimationDuration:2];
    [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
    [UIView setAnimationTransition:UIViewAnimationTransitionFlipFromLeft forView:self.view cache:NO];
    [self.view addSubview:loginScreen.view];
    [UIView commitAnimations];
}

然后在 ChooseLogin.m 中:

@implementation ChooseLogin


// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad
{
    [super viewDidLoad];
}


- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}

- (IBAction)parentLogin:(id)sender {

    NSLog(@":::::::");

    NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

    NSString *passwd = [prefs stringForKey:@"password"];

    NSLog(@"data saved");

    if (passwd == nil) {


    CreatePassword *cPassword = [[CreatePassword alloc] initWithNibName:@"CreatePassword" bundle:nil ];
        [UIView beginAnimations:@"flipview" context:nil];
        [UIView setAnimationDuration:1];
        [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
        [UIView setAnimationTransition:UIViewAnimationTransitionFlipFromLeft forView:self.view cache:NO];
        [self.view addSubview:cPassword.view];
        [UIView commitAnimations];

    }else {

        UserPassword *uPasswd = [[UserPassword alloc] initWithNibName:@"UserPassword" bundle:nil];
        [UIView beginAnimations:@"flipview" context:nil];
        [UIView setAnimationDuration:1];
        [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
        [UIView setAnimationTransition:UIViewAnimationTransitionFlipFromLeft forView:self.view cache:NO];
        [self.view addSubview:uPasswd.view];
        [UIView commitAnimations];

    }
}

- (IBAction)childLogin:(id)sender {

    ChildLogin *loginScreen = [[ChildLogin alloc] initWithNibName:@"ChildLogin" bundle:nil];
    [UIView beginAnimations:@"flipview" context:nil];
   // [UIView setAnimationDuration:1];
    [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
    [UIView setAnimationTransition:UIViewAnimationTransitionFlipFromLeft forView:self.view cache:NO];
    [self.view addSubview:loginScreen.view];
    [UIView commitAnimations];
}

@end

Answer 1

-[__NSCFTimer parentLogin:]: unrecognized selector sent to instance

这意味着消息被发送到一个该类无法识别的类——您要么没有编写这个自定义选择器(函数)，要么某个函数被发送到错误的类，因此是错误的'承认。在尝试编写代码时，XCode 通常很擅长捕捉这些，但它似乎不会在 XIB 文件中检查它们。

根据我的经验，此类问题最常见的原因是当您删除或重命名一个函数时，忘记更新与该类关联的 XIB 文件——或者您更新了它，它添加了新的函数的版本，不要忘记旧版本。