objective-c - NSScanner 无法识别 scanUpToString 上的选择器

Question

我使用 URL parser class来自 Dimitris，但我在初始化对象时遇到问题 initWithURLString:

- (id) initWithURLString:(NSString *)url{
    self = [super init];
    if (self != nil) {
        NSString *string = url;
        NSScanner *scanner = [NSScanner scannerWithString:string];
        [scanner setCharactersToBeSkipped:[NSCharacterSet characterSetWithCharactersInString:@"&?"]];
        NSString *tempString;
        NSMutableArray *vars = [NSMutableArray new];
        //ignore the beginning of the string and skip to the vars
        [scanner scanUpToString:@"?" intoString:nil];
        while ([scanner scanUpToString:@"&" intoString:&tempString]) {
            [vars addObject:[tempString copy]];
        }
        self.variables = vars;
    }
    return self;
}

在线[扫描仪 scanUpToString:@"?"intoString:nil]; 我收到错误:

[NSURL length]: unrecognized selector sent to instance 0x1f8c2050

这怎么可能？

编辑:也许你想知道我如何调用 URLParser:

URLParser *urlParser = [[URLParser alloc]initWithURLString:[info valueForKey:UIImagePickerControllerReferenceURL]];

UIImagePickerControllerReferenceURL 值为:assets-library://asset/asset.PNG?id=8D2F0449-11A3-4962-9D60-C446831645D7&ext=PNG

Answer 1

您将 NSURL 传递给 initWithURLString，但您应该将其与 NSString 一起使用，如下所示:

NSString* urlString = [NSString stringWithFormat:@"%@",[info valueForKey:UIImagePickerControllerReferenceURL]];
URLParser *parser = [[[URLParser alloc] initWithURLString:urlString] autorelease];