MFMessageComposeViewController iOS7 addAttachmentData:typeIdentifier:filename:not working

Question

我想在iOS7上将图像附加到MMS上.我写了以下代码:

    MFMessageComposeViewController *messageController = [[MFMessageComposeViewController alloc] init];
    messageController.messageComposeDelegate = self;

    NSData *imgData = [NSData dataWithContentsOfFile:@"blablabla"];
    BOOL didAttachImage = [messageController addAttachmentData:imgData typeIdentifier:@"public.data" filename:@"image"];

    if (didAttachImage)
    {
        // Present message view controller on screen
        [self presentViewController:messageController animated:YES completion:nil];
    }
    else
    {
        UIAlertView *warningAlert = [[UIAlertView alloc] initWithTitle:@"Error"
                                                               message:@"Failed to attach image"
                                                              delegate:nil
                                                     cancelButtonTitle:@"OK"
                                                     otherButtonTitles:nil];
        [warningAlert show];
        return;
    }

问题是,当显示SMS屏幕时,它无法识别图像,也无法发送.我看到这样的事情:

我相信这与我发送的imgData或者typeIdentifier有关.

注意:我尝试了几乎所有可能的typeIdentifiers:@"public.data",@"public.image",@"public.item",...等没有工作.

有人可以帮帮我吗？你使用的typeIdentifier是什么？我在iPhone 5,iOS 7.0.2上测试.

谢谢.

---

解:

正如Greg指示的那样,这解决了我的问题:将文件名设置为@"image.png",将typeIdentifier设置为kUTTypePNG.

[messageController addAttachmentData:imgData typeIdentifier:(NSString *)kUTTypePNG filename:@"image.png"];

谢谢格雷格.

Answer 1

MFMessageComposeViewController希望附件具有您正在上传的图像类型的正确扩展名.我通过测试PNG文件进行了验证,以及添加附件数据的以下变体:

[messageController addAttachmentData:imgData typeIdentifier:@"public.data" filename:@"image"];
[messageController addAttachmentData:imgData typeIdentifier:@"public.data" filename:@"image.abc"];
[messageController addAttachmentData:imgData typeIdentifier:@"public.data" filename:@"image.png"];

只有最后一个选项有效.我不需要更改typeIdentifier,尽管选择与数据类型匹配的UTI可能是有意义的.

完整的UTI列表可在此处获得:系统声明的统一类型标识符(感谢@iWasRobbed!)