ios - 循环遍历 URLS 的 NSArray - 崩溃 - iOS

Question

我希望遍历我的 NSArray *urls - 对每个对象进行一些字符串调整。

但是，一旦它进入 For 循环并尝试调整 NSString *thing - 这会引发异常。

关于为什么我感到困惑有什么想法吗？

 - (void)GetData
    {
        NSFileManager *fm = [NSFileManager defaultManager];
        NSString *directory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
        directory = [NSString stringWithFormat:@"%@/%@/%@/%@", directory, self.researcherID, self.participantID, testTypeString];
        directory = [directory stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
        NSError *error;
        NSURL *url = [NSURL URLWithString:directory];
        NSArray *urls = [fm contentsOfDirectoryAtURL:url includingPropertiesForKeys:nil options:0 error:&error];


        for (int x = 0; x < urls.count; x++) {

            NSString *urlIndex = urls[x];


            NSString *thing = [urlIndex stringByReplacingOccurrencesOfString:@"%20" withString:@" "];
            thing = [thing stringByReplacingOccurrencesOfString:@"file://" withString:@""];


            // add thing to new array but crashes before i can
        }
    }

编辑:异常抛出

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSURL stringByReplacingOccurrencesOfString:withString:]: unrecognized selector sent to instance 0x14ebf1a0'

Answer 1

NSArray *urls = [fm contentsOfDirectoryAtURL:url includingPropertiesForKeys:nil options:0 error:&error];

返回一组 NSURL 对象，而不是 NSString。您可以将 URL 转换为字符串简单地用

NSString *path = [urls[x] path];

这使得字符串操作过时了。或者，使用

NSArray *files = [fm contentsOfDirectoryAtPath:directory error:&error];

返回 NSString 对象数组而不是 NSURL。