打开文档的使用方法

#pragma mark Actions
- (IBAction)previewDocument:(id)sender {
    NSURL *URL = [[NSBundle mainBundle] URLForResource:@"sample" withExtension:@"pdf"];
    
    if (URL) {
        // Initialize Document Interaction Controller
        self.documentInteractionController = [UIDocumentInteractionController interactionControllerWithURL:URL];
        
        // Configure Document Interaction Controller
        [self.documentInteractionController setDelegate:self];
        
        // Preview PDF
        [self.documentInteractionController presentPreviewAnimated:YES];
    }
}

- (IBAction)openDocument:(id)sender {
    UIButton *button = (UIButton *)sender;
    NSURL *URL = [[NSBundle mainBundle] URLForResource:@"test" withExtension:@"pdf"];
    
    if (URL) {
        // Initialize Document Interaction Controller
        self.documentInteractionController = [UIDocumentInteractionController interactionControllerWithURL:URL];
        
        // Configure Document Interaction Controller
        [self.documentInteractionController setDelegate:self];
        
        // Present Open In Menu
        [self.documentInteractionController presentOpenInMenuFromRect:[button frame] inView:self.view animated:YES];
    }
}

#pragma mark -
#pragma mark Document Interaction Controller Delegate Methods
- (UIViewController *) documentInteractionControllerViewControllerForPreview: (UIDocumentInteractionController *) controller {
    return self;
}