我在 iOS 中使用从用于假装文件布局的UIKit各种文件创建 PDF文件。XIB
我可以成功生成 PDF 文件。但是我在主线程中这样做，我想将它移动到一个单独的线程中，这样 UI 就不会“冻结”。
我曾尝试使用 GCD 这样做，但它不起作用，并且它抛出了一些错误。
我有这样的事情：
[MBProgressHUD showHUDAddedTo:self.view animated:YES];
__block NSData *pdfNote = nil;
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0),^{
pdfNote = [self generatePdfFile];
dispatch_sync(dispatch_get_main_queue(),^{
[MBProgressHUD hideHUDForView:self.view animated:YES];
});
});
我看到的错误是：
failed to find PDF header: `%PDF' not found.
failed to find PDF header: `%PDF' not found.
failed to find PDF header: `%PDF' not found.
failed to find PDF header: `%PDF' not found.
2012-07-12 15:31:15.427 IrmaosPeixoto-CRM[7601:1a03] bool _WebTryThreadLock(bool), 0x3404d0: Tried to obtain the web lock from a thread other than the main thread or the web thread. This may be a result of calling to UIKit from a secondary thread. Crashing now...
1 _ZL17_WebTryThreadLockb
2 WebThreadLock
3 -[UITextView setFrame:]
4 UIViewCommonInitWithFrame
5 -[UIView initWithCoder:]
6 -[UIScrollView initWithCoder:]
7 -[UITextView initWithCoder:]
8 UINibDecoderDecodeObjectForValue
9 UINibDecoderDecodeObjectForValue
10 -[UINibDecoder decodeObjectForKey:]
11 -[UIView initWithCoder:]
12 -[UIClassSwapper initWithCoder:]
13 UINibDecoderDecodeObjectForValue
14 -[UINibDecoder decodeObjectForKey:]
15 -[UIRuntimeConnection initWithCoder:]
16 UINibDecoderDecodeObjectForValue
17 UINibDecoderDecodeObjectForValue
18 -[UINibDecoder decodeObjectForKey:]
19 -[UINib instantiateWithOwner:options:]
20 -[NSBundle(UINSBundleAdditions) loadNibNamed:owner:options:]
21 +[UIView(Extensions) loadFromNib:owner:]
22 -[FinishOrderViewController generatePdfFile]
23 __43-[FinishOrderViewController buttonPressed:]_block_invoke_0
24 _dispatch_call_block_and_release
25 _dispatch_worker_thread2
26 _pthread_wqthread
27 start_wqthread
附加说明：PDF 生成涉及对 Core Data 的一些访问以获取一些信息。
有没有更好的（工作）方式来实现我的需要？
编辑我弄错了，我使用UIKit而不是核心图形来生成 PDF。