//注意事项, info.plist 增加
Application supports iTunes file sharing: YES
Supports opening documents in place: YES

附录: 从系统Files App中读取文件

- (void)presentDocumentPicker {
    NSArray *documentTypes = @[@"public.content", @"public.text", @"public.source-code", @"public.image", @"public.audiovisual-content", @"com.adobe.pdf", @"com.apple.keynote.key", @"com.microsoft.word.doc", @"com.microsoft.excel.xls", @"com.microsoft.powerpoint.ppt"];
    
    /*
     UIDocumentPickerModeImport,//导入
     UIDocumentPickerModeOpen,//打开
     UIDocumentPickerModeExportToService,//导出
     UIDocumentPickerModeMoveToService//直接访问
     */
    UIDocumentPickerViewController *documentPickerViewController = [[UIDocumentPickerViewController alloc] initWithDocumentTypes:documentTypes inMode:UIDocumentPickerModeOpen];//UIDocumentPickerModeImport
    documentPickerViewController.delegate = self;
   
    [self presentViewController:documentPickerViewController animated:YES completion:nil];

}


- (void)documentPicker:(UIDocumentPickerViewController *)controller didPickDocumentsAtURLs:(NSArray<NSURL *> *)urls API_AVAILABLE(ios(11.0)) {
    //获取授权
    BOOL fileUrlAuthozied = [urls.firstObject startAccessingSecurityScopedResource];
    if (fileUrlAuthozied) {
        //通过文件协调工具来得到新的文件地址，以此得到文件保护功能
        NSFileCoordinator *fileCoordinator = [[NSFileCoordinator alloc] init];
        NSError *error;

        [fileCoordinator coordinateReadingItemAtURL:urls.firstObject options:0 error:&error byAccessor:^(NSURL *newURL) {
            [self handleReadingItemAtURL:newURL];
//            [self dismissViewControllerAnimated:YES completion:NULL];
        }];
        
        [urls.firstObject stopAccessingSecurityScopedResource];
        
    } else {
        //授权失败
        [self mb_showMessage:NSLocalizedString(@"打开失败", nil)];
    }
}

- (void)handleReadingItemAtURL:(NSURL *)newURL {
    //自身App路径判断
    NSString *documentsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];

    if ([newURL.absoluteString containsString:documentsPath]) {
        [self openFileWithUrl:newURL];
        return;
    }
    

    [self mb_Loading];
    
    NSString *fileName = [newURL lastPathComponent];
    NSError *error = nil;
    NSData *fileData = [NSData dataWithContentsOfURL:newURL options:NSDataReadingMappedIfSafe error:&error];
    
    if (error) {
        NSLog(@"error: %@",error);
        [self mb_showMessage:NSLocalizedString(@"打开失败", nil)];
    } else {
        /*
         file:///private/var/mobile/Containers/Data/Application/289E3E40-52D3-4187-8FC0-CE8EBABD565E/Documents/example2.MOV
         */
        NSLog(@"coordinateReadingItemAtURL: %@",newURL);
        
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
            
            NSString *path = [NSTemporaryDirectory() stringByAppendingPathComponent:fileName];
            BOOL ret = [fileData writeToFile:path atomically:YES];
            NSLog(@"写文件:%@", ret?@"成功":@"失败");
            
            if (ret) {
                dispatch_async(dispatch_get_main_queue(), ^{
                    [self mb_hideHUD];
                    
                    NSURL *playerURL = [NSURL fileURLWithPath:path];
                    [self openFileWithUrl:playerURL];
                    
                });
                
            } else {
                dispatch_async(dispatch_get_main_queue(), ^{
                    [self mb_showMessage:NSLocalizedString(@"打开失败", nil)];
                    
                });
            }
            
            
        });
        
    }
    
}