Xcode 随机字符串替换仅在模拟器中发生的字符串错误

所以我有一个奇怪的错误。我可以调试我的应用程序一整天没有任何问题，但突然出现了这个奇怪的错误消息，即使我没有改变任何东西

2013-04-21 01:06:26.617架构更新[4874:907]*由于未捕获的异常“NSInvalidArgumentException”而终止应用程序，原因：“*-[\uu NSCFString stringByReplacingOccurrencesOfString:withString:options:range:：nil参数” *第一次抛出调用堆栈： （0x3131f2a3 0x38fc497f 0x3131f1c5 0x31b8c9b5 0x31b8c95d 0x6765 0x58c3 0x3318e311 0x3319a79b 0x3319a4c1 0x3316b4e9 0x3312a803 0x32ed4d8b 0x32ed4929 0x32f037cf 0x331d40e9 0x331d32d5 0x331d24a7 0x331d2431 0x333083093190691 0x331903d5 0x3318fd3b 0x33186eab 0x3318AED 0x3318C41E9 0x331877F 0x3317A3317C5317A4 0xC3317A4 0xC3317A4 0x3317A4 0xE3417CDe2a1d3 0x312f4173 0x312f4117 0x312f2f99 0x31265ebd 0x31265d49 0x3317e485 0x3317B01 0x54cd 0x393fbb20） libc++abi.dylib:terminate调用引发异常 （lldb）

发生错误的My void：

- (void) loadSchema {

    NSURL *scriptUrl = [NSURL URLWithString:@"http://schemaappen.se/plist/risbergska.plist"];
    NSData *data = [NSData dataWithContentsOfURL:scriptUrl];
    if (data)
        NSLog(@"Device is connected to the internet");
    else{
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Ingen internetanslutning" message:@"Försök igen senare" delegate:self cancelButtonTitle:@"Okej" otherButtonTitles: nil];
        [alert show];
    }


    NSDateFormatter *f = [[NSDateFormatter alloc] init];
    [f setDateFormat:@"EEEE"];
    NSString *string = [f stringFromDate:[NSDate date]];

    unique = string;

    if ([unique isEqualToString:@"måndag"] || [unique isEqualToString:@"Monday"]) {
        dagen = @"1";
    }
    if ([unique isEqualToString:@"tisdag"] || [unique isEqualToString:@"Tuesday"]) {
        dagen = @"2";

    }
    if ([unique isEqualToString:@"onsdag"] || [unique isEqualToString:@"Wednesday"]) {
        dagen = @"4";
    }
    if ([unique isEqualToString:@"torsdag"] || [unique isEqualToString:@"Thursday"]) {
        dagen = @"8";
    }
    if ([unique isEqualToString:@"fredag"] || [unique isEqualToString:@"Friday"]) {
        dagen = @"16";
    }
    if ([unique isEqualToString:@"lördag"] || [unique isEqualToString:@"Saturday"]) {
        dagen = @"1";
    }
    if ([unique isEqualToString:@"söndag"] || [unique isEqualToString:@"Sunday"]) {
        dagen = @"1";
    }


    urlString = [[NSUserDefaults standardUserDefaults] valueForKey:@"SchemaURL"];


    NSRange rangeValue = [urlString rangeOfString:@"currentweek" options:NSCaseInsensitiveSearch];

    if (rangeValue.length > 0){
        weekURL = [urlString stringByReplacingOccurrencesOfString:@"currentweek" withString:weekNumber];
    }
    else {
        weekURL = urlString;
    }

    NSString *dayURL = [weekURL stringByReplacingOccurrencesOfString:@"dagen" withString:dagen];
    NSURL *url = [NSURL URLWithString:dayURL];
    NSURLRequest *req = [NSURLRequest requestWithURL:url];

    [webView loadRequest:req];

    [MBHUDView hudWithBody:@"Laddar schema..." type:MBAlertViewHUDTypeActivityIndicator hidesAfter:NO show:YES];

}

如果我在我的设备上运行应用程序而不通过xcode运行，那么应用程序工作正常。没有一次撞车

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有人知道为什么会发生这种情况吗？

应用程序在模拟器中崩溃的一个可能原因是访问文件时区分大小写。（模拟器区分大小写，设备不区分大小写）

1） 我会检查stringByReplacingOccurrencesOfString访问的任何文件名是否存在区分大小写的问题

2） 根据您的代码和给定的错误，我的第一个猜测是，weakNumber在导致崩溃的某个点上为零