关于从自定义App向iMessage（iPhone联系人）发送视频的技术问询

Absolutely, this is totally achievable on iOS! Let’s break down your options clearly, including whether URL schemes fit the bill.

Yes, 100%—iOS provides two robust approaches to send video attachments to iMessage directly from your custom app, plus a partial solution via URL schemes.

1. Using UIActivityViewController (Simplest, System-Native Approach) #

This is the easiest way to let users share your video via iMessage (or other apps like Mail/AirDrop). It uses iOS’s built-in share sheet, where users can select iMessage, pick a contact, and your video will automatically attach as a file.

Here’s a Swift code example:

import UIKit

func shareVideoToiMessage(videoURL: URL) {
    let activityViewController = UIActivityViewController(activityItems: [videoURL], applicationActivities: nil)
    
    // Optional: Filter out unwanted share options to focus on iMessage
    activityViewController.excludedActivityTypes = [
        .airDrop,
        .mail,
        .postToFacebook
    ]
    
    // Present the share sheet (call this from a UIViewController)
    if let topViewController = UIApplication.shared.keyWindow?.rootViewController {
        topViewController.present(activityViewController, animated: true)
    }
}

When the user selects iMessage from the sheet, the video will be attached to a new message, and they can choose their desired contact to send it to.

2. Using MFMessageComposeViewController (Direct, Contact-Specific Control) #

If you want to skip the share sheet and directly open an iMessage compose window pre-filled with a specific contact and your video attachment, use the MessageUI framework. This gives you tighter control over the recipient and pre-attached content.

First, import the MessageUI framework, then use this code:

import UIKit
import MessageUI

func sendVideoToTargetContact(videoURL: URL, contactIdentifier: String) {
    // Check if the device supports iMessage and attachments
    guard MFMessageComposeViewController.canSendText(),
          MFMessageComposeViewController.canSendAttachments() else {
        // Handle unsupported device scenario
        let alert = UIAlertController(title: "Unsupported", message: "This device can't send iMessage attachments.", preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "OK", style: .default))
        UIApplication.shared.keyWindow?.rootViewController?.present(alert, animated: true)
        return
    }
    
    let messageComposer = MFMessageComposeViewController()
    messageComposer.messageComposeDelegate = self // Ensure your VC conforms to this delegate
    messageComposer.recipients = [contactIdentifier] // Use phone number or Apple ID email
    messageComposer.addAttachmentURL(videoURL, withAlternateFilename: "MyVideo.mp4")
    
    // Present the pre-filled compose window
    if let topViewController = UIApplication.shared.keyWindow?.rootViewController {
        topViewController.present(messageComposer, animated: true)
    }
}

// Delegate method to dismiss the compose window when done
extension YourViewController: MFMessageComposeViewControllerDelegate {
    func messageComposeViewController(_ controller: MFMessageComposeViewController, didFinishWith result: MessageComposeResult) {
        controller.dismiss(animated: true)
    }
}

This will open the iMessage compose screen directly with your video attached and the specified contact pre-selected.

iMessage does have a URL scheme (imessage://), but it has critical limitations for your full requirement:

• You can use it to open iMessage and target a specific contact, like:

  imessage://?address=+1234567890
  

• However, you cannot attach a video file via the URL scheme—there’s no supported parameter to pass file attachments. This means you can open the conversation with a contact, but the user will have to manually add the video from your app or files.

So URL schemes can handle part of your workflow (opening the right conversation), but not the full requirement of automatically attaching the video.

• Ensure your video uses an iMessage-supported format (MP4, MOV are safe choices) and stays under iMessage’s file size limit (typically ~100MB, though this can vary by carrier and iOS version).
• For MFMessageComposeViewController, always handle cases where the device doesn’t support iMessage (e.g., a Wi-Fi-only iPad).

内容的提问来源于stack exchange，提问作者Usman Mughal