ios - Objective-C : Download PDF and Open in iBooks

Question

我正在制作一个应用程序，它从在线服务器下载文件并将其保存到应用程序的本地内存中。现在，我想要做的是当您单击“查看 PDF”按钮时，它会直接打开 PDF 文件到 iBooks。

这是我保存文件的代码:

        currentURL = @"http://weblink.com/folder1/folder2/file.pdf";
        NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:currentURL]];

        NSURLConnection *conn = [[NSURLConnection alloc] init];
    (void)[conn initWithRequest:request delegate:self];

    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0ul);
    dispatch_async(queue, ^{
        data = [NSData dataWithContentsOfURL:[NSURL URLWithString:currentURL]];
        dispatch_sync(dispatch_get_main_queue(), ^{
        });
        resourceDocPath = [[NSString alloc] initWithString:[[[[NSBundle mainBundle]  resourcePath] stringByDeletingLastPathComponent] stringByAppendingPathComponent:@"Documents"]];

        filePath = [resourceDocPath stringByAppendingPathComponent:@"myPDF.pdf"];
        [data writeToFile:filePath atomically:YES];
    });

这是我从互联网上找到的用于将文件打开到 iBooks 的内容(我将此代码放在按钮单击上):

    NSString *path = [[NSBundle mainBundle] pathForResource:@"myPDF" ofType:@"pdf"];
    NSURL *url = [NSURL fileURLWithPath:path];
    UIDocumentInteractionController *docController = [[UIDocumentInteractionController alloc] init];

    docController = [UIDocumentInteractionController interactionControllerWithURL:url];
    docController.delegate = self;

该应用程序因该代码和此消息而崩溃:

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSURL initFileURLWithPath:]: nil string parameter'

Answer 1

比较写入时的文件路径和读取时的路径。它们对我来说看起来不一样，所以您可能在按钮点击代码中有一个无效/零引用。