iphone - 从 NSMutableArray 下载时“for”循环崩溃

Question

我的 NSMutableArray 中有 4 个元素。我有用于下载文件和在 UITextView 中显示文件数据以用于测试目的的简洁代码。没有 for 循环，一切都很好。给我问题的代码在这个函数中:

- (void)complexDownload {
    int i;
    for (i=0; i < downloadArray.count; i++) {
        if (isBusy == NO) {
            [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];
            downloadURL = [downloadArray objectAtIndex:i];
            NSLog(@"URL is %@", downloadURL);
            NSLog(@"Downloading object at index %i", i);
            NSURL *url = downloadURL;
            NSURLRequest *theRequest=[NSURLRequest requestWithURL:url
                                                      cachePolicy:NSURLRequestUseProtocolCachePolicy
                                                  timeoutInterval:60.0];

            NSURLConnection *theConnection = [NSURLConnection connectionWithRequest:theRequest delegate:self];

                if (theConnection) {
                    self.downloadData = [NSMutableData data];
                    isBusy = YES;
                    NSLog(@"Busy value in download cycle equals %i, downloading", isBusy);
                } else {
                    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
                    NSLog(@"Connection failed");
                    isBusy = NO;
                }
        }
    }
}

我最初认为问题可能出在 isBusy BOOL 中，但即使没有 if 条件，应用程序也会崩溃。编译器没有给我任何错误，但有一个错误: Here's the link for the big screenshot .

其余函数如下:

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
    [downloadData appendData:data];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    NSString *dataString = [[NSString alloc] initWithData:downloadData encoding:NSASCIIStringEncoding];
    self.dataTextView.text = dataString;
    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
    NSLog(@"Download finished!");
    isBusy = NO;
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
    NSLog(@"%@", error);
    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
}

所有的 NSLogged 值都很好，Array 有链接并且所有链接都是正确的。

Answer 1

我的猜测是，在某些时候 downloadArray[i] 在某些时候损坏了，或者它不是 NSUrl。代码在 [NSURLRequest requestWithURL...] 调用的 CFURLCopyAbsoluteURL() 中崩溃。