objective-c - iOS EXC_BAD_ACCESS 类中的错误

Question

我在我的应用程序中遇到了 EXC_BAD_ACCESS 错误。或者在我的一门课上更具体一些。它是自定义 UIAlertView 类。当它在使用中抛出 EXC_BAD_ACCESS 时我无法捕捉到。有时它的效果正如预期的那样好，但突然间它就崩溃了……这是全类同学

@implementation AlertPassword
int counter = 3;
@synthesize done;
@synthesize alertText;
@synthesize msg;
- (void) showAlert :(NSString*) title
{
    if(counter != 3){
        if(counter == 1)
        {
            NSString *msgs = @"Last warning";
            msg = msgs;
        }
        else
        {
            NSString *msgs = [NSString stringWithFormat:@"WRONG PIN. %d times remaining",counter];
            msg = msgs;

        }
    }
    else
    {
        NSString *msgs = @"Enter your pin";
        msg = msgs;
    }
    UIAlertView * alert = [[UIAlertView alloc] initWithTitle:@"Security" message:msg delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles: nil];
    _alert = alert;
    _alert.alertViewStyle = UIAlertViewStyleSecureTextInput;
    alertText = [_alert textFieldAtIndex:0];
    alertText.keyboardType = UIKeyboardTypeNumberPad;
    alertText.placeholder = @"Pin";
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(controlTextDidChange:)
                                                 name:UITextFieldTextDidChangeNotification object:alertText];
    [_alert show];
    [_alert release];
    [[NSNotificationCenter defaultCenter] removeObserver:UITextFieldTextDidChangeNotification];
}


- (void)controlTextDidChange:(NSNotification *)notification {
    {
        NSString *pin = [[NSUserDefaults standardUserDefaults] stringForKey:@"Pin"];
        if ([notification object] == alertText)
        {
            if (alertText.text.length == pin.length)
            {
                if(counter != 0)
                {

                    if([alertText.text isEqualToString:pin])
                    {
                            [_alert dismissWithClickedButtonIndex:0 animated:NO];
                            [self.tableViewController openSettings];
                            counter = 3;
                    }
                    else
                    {
                            counter--;
                            [_alert dismissWithClickedButtonIndex:0 animated:NO];
                            [self showAlert:@""];

                    }
                }
                else
                {
                    [_alert dismissWithClickedButtonIndex:0 animated:NO];
                    [[NSUserDefaults standardUserDefaults] setObject:NULL
                                                              forKey:@"Telephone"];
                    [[NSUserDefaults standardUserDefaults] setObject:NULL
                                                              forKey:@"Pin"];
                    [[NSUserDefaults standardUserDefaults] synchronize];
                    UIAlertView *av = [[UIAlertView alloc] initWithTitle:@"" message:AMLocalizedString(@"EraseData", nil) delegate:nil cancelButtonTitle:AMLocalizedString(@"Ok", nil) otherButtonTitles:nil];
                    counter = 3;
                    [av show];
                    [av release];
                }

            }
        }
    }

}
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
    NSString *pincheck = [[NSUserDefaults standardUserDefaults] stringForKey:@"pinCheck"];
    if (buttonIndex == 0)
    {
        if(pincheck.intValue == 1)
        {
           NSLog(@"app kill");
            exit(0);
        }
        else
        {
            NSLog(@"dismiss");
        }
    }

}
@end

这是我初始化和使用此类的地方。

            case 5:
            NSLog(@"Add remove");
            if (pincheck != NULL && pin != NULL){
                if([pincheck isEqualToString:@"0"])
                {

                    AlertPassword *alert = [AlertPassword alloc];
                    alert.tableViewController = self;
                    NSString *msg = @"Enter your pin code to access:";
                    [alert showAlert:msg];
                //    [alert release];

                }
                break;
            }
            else
            {
                NSLog(@"Is null");
                [Menu load2View:self];
            }
            break;

我想也许是因为我没有发布警报。但是添加 [alert release]; 使得在用户尝试输入内容后立即具有 EXC_BAD_ACCESS 。没有[alert release];它就可以工作。但有时它会因 EXC_BAD_ACCESS 而崩溃

有时也会这样

2012-11-08 12:11:27.451 kodinisRaktas[2485:19d03] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSMallocBlock__ dismissWithClickedButtonIndex:animated:]: unrecognized selector sent to instance 0x947aae0'

但我也不知道为什么会发生这种情况

请帮忙，我对 Objective-C 和 ios 还很陌生，我不知道如何摆脱这个问题，我想有一点经验的人会发现我的代码有什么问题。

我刚刚看到，如果您按取消键 4-5 次或更多次，然后尝试输入某些内容，则会抛出 EXC_BAD_ACCESS 或无法识别的选择器。

Answer 1

EXC_BAD_ACCESS 主要是由于内存处理不当造成的。该警报很可能已成为僵尸...我会将警报作为具有强/保留的属性。展示时您应该握住它。 “表演”后不发布。

当你设置第一个时，你可以这样做

_alert = [[UIAlertView alloc] initWithTitle:@"Security" message:msg delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles: nil]; // retain count: 1

请注意，调用“show”也会保留它，但这不会改变您也需要保留它的事实。

[_alert show]; // retain count: 2

等待委托(delegate)回调并释放它。

- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex {
    [_alert release], _alert = nil; // retain count in next run will be 0
}

提示:如果使用 UIAlertView 结合 block 可能会更容易处理。 http://gkoreman.com/blog/2011/02/15/uialertview-with-blocks/