Swift/Objective-C集成MailCore2后无法获取收件箱，求方案或替代框架

Hey there! I notice you’ve successfully got MailCore2 up and running for sending emails (nice work checking off all those setup steps!) but hit a snag when trying to pull content from the inbox. Before diving into alternatives, a quick sanity check: have you double-checked your MCOIMAPSession configuration? MailCore2 does support IMAP inbox fetching—make sure your host, port, encryption settings, and authentication details are correct, and that you’re using the right fetch methods like fetchMessagesByUIDOperationWithFolder:requestKind:.

If you still want to explore other frameworks, here are reliable, battle-tested options tailored for iOS:

• MessageUI (Apple's Official Framework)
  This is the system-native tool for mail interactions. While it doesn’t let you fetch inbox content directly inside your app, it lets you launch the system Mail app to access the inbox. Perfect if you don’t need a full in-app mail client and just want to let users access their emails via Apple’s trusted system interface.

• MailKit
  A modern, Swift-first framework that supports IMAP, POP3, and SMTP. It’s built to feel natural with Swift’s conventions, making it easy to fetch inbox lists, parse email content, and manage folders. It’s actively maintained and has clear documentation to get you up and running quickly.

• libetpan
  This is the low-level mail protocol library that MailCore2 is built on. If you want granular control over underlying IMAP operations, using libetpan directly gives you that flexibility. It’s more complex than higher-level frameworks, but it’s ideal if you need custom behavior that MailCore2 doesn’t support out of the box.

• Postmark SDK
  If you’re working specifically with Postmark’s email service, their official iOS SDK simplifies fetching inbox emails. Note that this is service-specific, so it only works with Postmark, but it’s incredibly straightforward if that’s your tech stack.

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