文件导入

- (void)importFile {
    NSArray *types = @[]; // 可以选择的文件类型
        UIDocumentPickerViewController *documentPicker = [[UIDocumentPickerViewController alloc] initWithDocumentTypes:types inMode:UIDocumentPickerModeOpen];
        documentPicker.delegate = self;
        documentPicker.modalPresentationStyle = UIModalPresentationFullScreen;
        [self presentViewController:documentPicker animated:YES completion:nil];
}
#pragma mark - <UIDocumentPickerDelegate>

- (void)documentPicker:(UIDocumentPickerViewController *)controller didPickDocumentsAtURLs:(NSArray <NSURL *>*)urls API_AVAILABLE(ios(11.0)){
    NSURL *url = urls[0];
    BOOL canAccessingResource = [url startAccessingSecurityScopedResource];
    if(canAccessingResource) {
        NSFileCoordinator *fileCoordinator = [[NSFileCoordinator alloc] init];
        NSError *error;
        [fileCoordinator coordinateReadingItemAtURL:url options:0 error:&error byAccessor:^(NSURL *newURL) {
            NSData *fileData = [NSData dataWithContentsOfURL:newURL];
            NSArray *arr = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
            NSString *documentPath = [arr lastObject];
            NSString *desFileName = [documentPath stringByAppendingPathComponent:self.fileName];
            [fileData writeToFile:desFileName atomically:YES];
            [self dismissViewControllerAnimated:YES completion:NULL];
        }];
        if (error) {
            // error handing
        }
    } else {
        // startAccessingSecurityScopedResource fail
    }
    [url stopAccessingSecurityScopedResource];
    
}

- (void)documentPickerWasCancelled:(UIDocumentPickerViewController *)controller {
    NSLog(@"取消");
}

文件导出

- (void)exportFile:(NSString *)fileName {
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
    // 保存文件的名称
    NSString *filePath = [[paths objectAtIndex:0] stringByAppendingPathComponent:fileName];
    UIDocumentPickerViewController *vccc = [[UIDocumentPickerViewController alloc]initWithURL:[NSURL fileURLWithPath:filePath] inMode:UIDocumentPickerModeExportToService];
    [self presentViewController:vccc animated:YES completion:nil];
}

Demo

MacCatalyst文件导入导出