Iphone ios6中的UIDocumentInteractionController预览.ics

iOS6和xcode 5.01

当我使用iphone模拟器运行时，它可以预览文件，但使用设备时，它失败了

//device path
NSString *path = @"/var/mobile/Applications/1AE864F5-A57F-47E7-829E-69DCFC63D8CD/tmp/11523invite.ics";
UIDocumentInteractionController *controller = [UIDocumentInteractionController interactionControllerWithURL:[NSURL fileURLWithPath:path isDirectory:NO]];
controller.delegate =self;
[controller presentPreviewAnimated:YES];

发生了什么事

@property (nonatomic, retain) UIDocumentInteractionController *docController;

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UIDocumentInteractionController的use属性

设备路径为静态或在运行时生成/var/mobile/Applications/1AE864F5-A57F-47E7-829E-69DCFC63D8CD/tmp/11523invite.ics。@PiyushDubey在rum时间生成。