ios – UIDocumentInteractionController“invalid scheme(null)”

我试图用UIDocumenTinteractionController预览文档.
该文件是我的应用程序从网络下载的.xls文件.我不断得到这个错误：

'UIDocumenTinteractionController: invalid scheR_332_11845@e (null).  Only the file scheR_332_11845@e is supported.'

我使用下面的代码：

- (void) webserviceController:(WebserviceController *)webserviceController returnedArray:(NSMutableArray *)array {
    if ([webserviceController.webrequest isEqualToString: @"generateExcelFileForemployee"]) {
        // start previewing the document at the current section index
        NSString *link = [[NSString StringWithString:array[0]] StringByreplacingoccurrencesOfString:@"AdminFunctions.PHP" withString:@"AdminFunctions.xls"];
        link = [[[link StringByreplacingoccurrencesOfString:@"\\" withString:@""]StringByreplacingoccurrencesOfString:@"/public/sites/" withString:@"http://"]StringByreplacingoccurrencesOfString:@"\"\\\"" withString:@""];
        NSLog(@"%@",link);
        NSData *urlData = [NSData dataWithContentsOfURL:[NSURL URLWithString:link]];

        NSArray   *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
        NSString  *documentsDirectory = [paths objectATindex:0];

        NSString  *filePath = [NSString StringWithFormat:@"%@/%@",documentsDirectory,@"AdminFunctions.xls"];

        BOOL isWritesuccess = [urlData writeToFile:filePath atomically:YES];
        NSLog(@"%@",filePath);

        if(isWritesuccess) //success
        {
            file = [NSURL fileURLWithPath:filePath];

            self.fileView = [self setupControllerWithURL:file usingDelegate:self];

            [self.fileView presentPreviewAnimated:YES];
        }
        else
        {
           NSLog(@"file not written");
        }
    }
}

- (UIDocumenTinteractionController *) setupControllerWithURL: (NSURL*) fileURL usingDelegate: (id <UIDocumenTinteractionControllerDelegate>) interactionDelegate {

    UIDocumenTinteractionController *interactionController =
    [UIDocumenTinteractionController interactionControllerWithURL: fileURL];
    interactionController.delegate = interactionDelegate;

    return interactionController;
}

- (UIViewController *) documenTinteractionControllerViewControllerForPreview: (UIDocumenTinteractionController *) controller {
    return self;
}

这两种方法都在我想呈现预览的viewcontroller中实现.我知道很难,我得到的数据在urlData对象,因为当我放入断点,控制台说,它包含6144字节,这正是要下载的文件的大小.

我一直在寻找这个安静的一段时间,但我似乎无法弄清楚如何解决这个问题.我已经尝试将link对象作为documenTinteractionController的源,但是错误更改为：

'UIDocumenTinteractionController: invalid scheR_332_11845@e (http).  Only the file scheR_332_11845@e is supported.'

任何关于如何克服这个问题的意见将被高度赞赏

file = [NSURL fileURLWithPath:filePath];

file = [NSURL URLWithString:filePath];