ios - UIDocumentInteractionController & ARC : [UIPopoverController dealloc] reached while popover is still visible

Question

之前已在此处讨论过此问题或类似问题，但我没有找到任何适合我的解决方案。

我正在使用以下代码显示 UIDocumentInteractionController在启用 ARC 的 iOS 7 项目上:

- (void) exportDoc{
    // [...]
    docController = [UIDocumentInteractionController interactionControllerWithURL:[NSURL fileURLWithPath:path]];
    docController.delegate = self;
    [docController presentOpenInMenuFromBarButtonItem:mainMenuButton animated:YES];
}

首先，我不想创建一个包含 Controller 引用的属性，但正如许多人所说，没有替代品。它被定义为

@property (strong) UIDocumentInteractionController* docController;

exportDoc使用 NSOperationQueue 在主线程中运行.每当执行它时，我都会收到以下错误消息:

Terminating app due to uncaught exception 'NSGenericException', reason: '-[UIPopoverController dealloc] reached while popover is still visible.'

这就是回溯所说的:

(lldb) bt* thread #1: tid = 0x1c97d9, 0x000000019a23c1c0 libobjc.A.dylib`objc_exception_throw, queue = 'com.apple.main-thread',stop reason = breakpoint 2.1    frame #0: 0x000000019a23c1c0 libobjc.A.dylib`objc_exception_throw    frame #1: 0x000000018d982e90 CoreFoundation`+[NSException raise:format:] + 128    frame #2: 0x0000000190bc348c UIKit`-[UIPopoverController dealloc] + 96    frame #3: 0x0000000190e18fc8 UIKit`-[UIDocumentInteractionController dealloc] + 168    frame #4: 0x000000019a255474 libobjc.A.dylib`(anonymous namespace)::AutoreleasePoolPage::pop(void*) + 524    frame #5: 0x000000018d881988 CoreFoundation`_CFAutoreleasePoolPop + 28    frame #6: 0x000000018e42cb18 Foundation`-[__NSOperationInternal _start:] + 892    frame #7: 0x000000018e4eea38 Foundation`__NSOQSchedule_f + 76    frame #8: 0x000000019a813fd4 libdispatch.dylib`_dispatch_client_callout + 16    frame #9: 0x000000019a8171dc libdispatch.dylib`_dispatch_main_queue_callback_4CF + 336    frame #10: 0x000000018d942c2c CoreFoundation`__CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 12    frame #11: 0x000000018d940f6c CoreFoundation`__CFRunLoopRun + 1452    frame #12: 0x000000018d881c20 CoreFoundation`CFRunLoopRunSpecific + 452    frame #13: 0x0000000193511c0c GraphicsServices`GSEventRunModal + 168    frame #14: 0x00000001909b2fdc UIKit`UIApplicationMain + 1156   * frame #15: 0x000000010000947c MyApplication`main(argc=1,argv=0x000000016fdfbc80) + 108 at main.m:16    frame #16: 0x000000019a82faa0 libdyld.dylib`start + 4

据我了解，自动释放池只是释放 Controller 。难道不应该像我一样使用强大的属性来防止这种情况吗？

您知道问题可能是什么以及我该如何解决吗？

[编辑]

我禁用了 ARC 并手动添加了 [docController retain]并让它工作。我想知道我的项目是否真的启用了 ARC 并尝试了以下预处理器代码

#if !__has_feature(objc_arc)
  #error no arc
#endif

但不显示错误。

Answer 1

似乎您正在使用的 docController 是一个局部变量，而不是一个类级别的变量。当您使用局部变量时，它会被释放。您是否尝试使用该属性而不是 iVar，如下所示。

- (void) exportDoc{
    // [...]
   self.docController = [UIDocumentInteractionController interactionControllerWithURL:[NSURL fileURLWithPath:path]];
   self.docController.delegate = self;
   [self.docController presentOpenInMenuFromBarButtonItem:mainMenuButton animated:YES];
}