UIAlertView crashes when added to app

问题

I am trying to impliment a basic UIAlertView into my app (I am using storyboard). But when I run my app, it goes to the debugger screen after stalling at the app's loading screen.

my .h:

    #import <UIKit/UIKit.h>
    @interface MindTripAnim :UIViewController {   
      IBOutlet UIImageView *animation;
    }

    - (IBAction)showMessage:(id)sender;

    @end

and my .m:

#import "MindTripAnim.h"
@interface MindTripAnim ()
@end

@implementation MindTripAnim

- (void)viewDidLoad {
   animation.animationImages = [NSArray arrayWithObjects:
                             [UIImage imageNamed:@"trips1.png"],
                             [UIImage imageNamed:@"trips2.png"],
                             [UIImage imageNamed:@"trips3.png"],
                             [UIImage imageNamed:@"trips4.png"],
                             [UIImage imageNamed:@"trips5.png"],                          
                             [UIImage imageNamed:@"trips6.png"],nil];
   [animation setAnimationRepeatCount:0];    
   animation.animationDuration = 0.65; 
   [animation startAnimating]; 
}

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

- (IBAction)showMessage:(id)sender
{
    UIAlertView *message = [[UIAlertView alloc] initWithTitle:@"Hello World!" message:@"This is your first UIAlertview message." delegate:nil cancelButtonTitle:@"Close" otherButtonTitles:nil];
    [message show];
}
@end

I am not sure what I am doing wrong, or why the app keeps stalling at the loading screen, please help!

I found this in the debugger

2012-12-01 19:39:03.428 MindTrip[3327:11303] * Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[ setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key Alert.' * First throw call stack: (0x1c9a012 0x10d7e7e 0x1d22fb1 0xb84711 0xb05ec8 0xb059b7 0xb30428 0x23c0cc 0x10eb663 0x1c9545a 0x23abcf 0xffe37 0x100418 0x100648 0x100882 0x4fa25 0x4fdbf 0x4ff55 0x58f67 0x1cfcc 0x1dfab 0x2f315 0x3024b 0x21cf8 0x1bf5df9 0x1bf5ad0 0x1c0fbf5 0x1c0f962 0x1c40bb6 0x1c3ff44 0x1c3fe1b 0x1d7da 0x1f65c 0x2a4d 0x2975) libc++abi.dylib: terminate called throwing an exception (lldb)

回答1:

The issue is that you have added alert(or a pointer to some view called alert) in your storyboard but the same is not added to the class code. If you are displaying the alert view programmatically, you can remove it from the storyboard.

来源：https://stackoverflow.com/questions/13665396/uialertview-crashes-when-added-to-app

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iphone

ios

xcode

uialertview

iboutlet