error = Error Domain=NSCocoaErrorDomain Code=3840

json解析，同樣的請求，有一個請求，無反應。糾結了幾天，終於解決了。

error = Error Domain=NSCocoaErrorDomain Code=3840 "Unescaped control character around character 168." UserInfo={NSDebugDescription=Unescaped control character around character 168.}

報錯信息如上：

 

這個原因，是因為服務器返回的字符串里面有換行符，所以我們要在接收到的數據里面，將換行符替換掉，然后再轉模型。

但是，AFN解析，並沒有提供原有的數據給我們（我沒找），就直接去了error 的接口。

然后用session的dataTask，用字符串轉它返回的data，則能夠把數據讀取出來，打印，果然有換行符。於是，改寫了原來的方法，用session去代替。

    NSString * url = infoCategoryM.listUrl;
    NSURL * URL = [NSURL URLWithString:url];
    NSURLRequest * request = [NSURLRequest requestWithURL:URL];
    NSURLSession * session = [NSURLSession sharedSession];
    NSURLSessionDataTask * dataTask = [session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        NSString * str = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
        NSString * str2 = [str stringByReplacingOccurrencesOfString:@"\t" withString:@""];
        str2 = [str2 stringByReplacingOccurrencesOfString:@"\n" withString:@""];
        str2 = [str2 stringByReplacingOccurrencesOfString:@"\r" withString:@""];
        
        ContentListArrM * contentListArrM = [[ContentListArrM alloc]initWithString:str2 error:nil];
        [self.contentListArr removeAllObjects];
        for (int i = 0; i < contentListArrM.contentList.count ; i++) {
            ContentListM * m = [contentListArrM.contentList objectAtIndex:i];
            if (![XSDKResourceUtil xsdkstringIsnilOrEmpty:m.title]) {
                [self.contentListArr addObject:m];
            }
        }
        dispatch_async(dispatch_get_main_queue(), ^{
            [self.infoTableView reloadData];
            self.selectedButton.selected = NO;
            selectedButton.selected = YES;
            self.selectedButton = selectedButton;
            NewsTableViewCell * cell = [self.infoTableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:1 inSection:0]];
            cell.selected = YES;
        });
        
    }];
    [dataTask resume];

　　里面，替換掉了換行符等其他字符，然后再轉模型。

This application is modifying the autolayout engine from a background thread, which can lead to engine corruption and weird crashes.  This will cause an exception in a future release.

這個錯誤，是告訴我們，要在主線程里面更新UI。