iOS11 新出的可以从"文件"中选择附件

1.跳转"文件"，选择数据

NSArray *types = @[
        
        @"public.jpeg",
        
        @"public.png",
        
        @"public.mpeg-4",
        
        @"com.apple.quicktime-movie",
        
        @"com.microsoft.powerpoint.ppt",
        
        @"com.microsoft.excel.xls",
        
        @"com.microsoft.powerpoint.pptx",
        
        @"com.microsoft.word.doc",
        
        @"com.microsoft.word.docx",
        
        @"com.microsoft.excel.xlsx",
        
        @"com.microsoft.excel.xls",
        
        @"public.item",
        
        @"public.html",
        
        @"public.avi",

        @"public.3gpp",
        
        @"public.mpeg-4",
        
        @"public.plain-text",
        
        @"com.adobe.pdf",
        
    ];
    
    UIDocumentPickerViewController *documentPicker = [[UIDocumentPickerViewController alloc] initWithDocumentTypes:types inMode:UIDocumentPickerModeImport];
    documentPicker.delegate = self;
    
    if (@available(iOS 11.0, *)) {
        [UINavigationBar appearanceWhenContainedInInstancesOfClasses:@[UIDocumentBrowserViewController.class]].tintColor = kColorDarkRed;
    }
    
    if (@available(iOS 11.0, *)) {
        documentPicker.allowsMultipleSelection = YES;
    }
    [controller presentViewController:documentPicker animated:YES completion:nil];

官方文档：https://developer.apple.com/library/archive/documentation/Miscellaneous/Reference/UTIRef/Articles/System-DeclaredUniformTypeIdentifiers.html#//apple_ref/doc/uid/TP40009259-SW1
types中是根据文档获取的，里面有各种附件的类型

2.实现代理 UIDocumentPickerDelegate
将文件保存到沙盒目录中，得到url
最后上传，这里没写

- (void)documentPicker:(UIDocumentPickerViewController *)controller didPickDocumentsAtURLs:(NSArray <NSURL *>*)urls
{
    [self handleDocumentPicker:controller didPickDocumentsAtURLs:urls];
}

- (void)documentPickerWasCancelled:(UIDocumentPickerViewController *)controller
{
    NSLog(@"用户取消了选择!");
}

- (void)documentPicker:(UIDocumentPickerViewController *)controller
  didPickDocumentAtURL:(NSURL *)url
{
    [self handleDocumentPicker:controller didPickDocumentsAtURLs:@[url]];
}

- (void)handleDocumentPicker:(UIDocumentPickerViewController *)controller didPickDocumentsAtURLs:(NSArray <NSURL *>*)urls
{
    // 将文件复制到Cache文件夹下
    NSArray *newUrls = [self copyFilesToCacheWithOriginalUrls:urls];
    
   // 得到文件的沙盒目录地址
}

- (NSArray<NSURL *> *)copyFilesToCacheWithOriginalUrls:(NSArray <NSURL *>*)urls
{
    if (urls == nil || urls.count == 0) {
        return @[];
    }
    NSMutableArray<NSURL *> *arrFileUrls = [NSMutableArray new];
    long currMillisecond = [[NSDate date] timeIntervalSince1970] * 1000;
    NSFileManager *fileManager = [NSFileManager defaultManager];
    
    for (NSURL *url in urls) {
        NSString *cachePath = NSSearchPathForDirectoriesInDomains(NSCachesDirectory
                                                                  , NSUserDomainMask
                                                                  , YES).lastObject;
        
        NSString *finderPath = [NSString stringWithFormat:@"%@/%ld/", cachePath, currMillisecond];
        if ([fileManager fileExistsAtPath:finderPath] == NO) {
            [fileManager createDirectoryAtPath:finderPath withIntermediateDirectories:YES attributes:nil error:nil];
        }
        
        NSString *filePath = [finderPath stringByAppendingPathComponent:url.lastPathComponent];
        
        if ([fileManager fileExistsAtPath:filePath]) {
            NSError *error = nil;
            [fileManager removeItemAtPath:filePath error:&error];
            if (error) NSLog(@"error : %@", error);
        }
        
        NSData *fileData = [NSData dataWithContentsOfURL:url];
        BOOL success =  [fileData writeToFile:filePath atomically:YES];
        if (success) {
            NSLog(@"file copy success");
            [arrFileUrls addObject:[NSURL fileURLWithPath:filePath]];
        }else{
            NSLog(@"file copy fail");
        }
    }
    
    return arrFileUrls;
}