1. IM
Jitsi is an audio/video and chat communicator that supports protocols such as SIP, XMPP/Jabber, AIM/ICQ, Windows Live, Yahoo! and many other useful features.
Although jitsi is a java video tool, it can be ported to android.
Jitsi is an open source, secure (ZRTP encrypted), high-quality SIP/XMPP video call, conferencing, chat, desktop sharing, file transfer. Can be installed on your favorite operating system and supports multiple IM networks. Jitsi is the most complete advanced communication tool available. Jitsi allows you to communicate with Facebook, GoogleTalk, XMPP, Windows Live, Yahoo!, AIM and ICQ in the same software.
Open source Jabber (XMPP) client with multi-account support, clean and simple interface. Being both free (as in freedom!) and ad-free, Xabber is designed to be the best Jabber client for Android.
Beem is an XMPP (jabber) client software running on the Android mobile platform, compatible with standard XMPP servers and services, such as Ejabberd, Openfire, Facebook, and Gmail). Supports SASL, proxy (Socks4, Socks5, HTTP), DNS SRV, and chatting with a specific resource.
Android jChat is a location-based chat software for Android mobile phones, using P2P communication mechanism.
Sipdroid is a SIP/VoIP client running on the Android mobile platform.
The open source IM in CSDN seems to work pretty well.
7. Enbu Internet Enterprise IM is a free enterprise instant messaging software. Its main functions support text, expressions, pictures, file sharing, voice and video, cloud disk, groups, enterprise organizational structure, offline messages, offline files and other functions; open to PC, Android and IOS mobile phone source code opens PC SDK API, JQUERY SDK, REST API, Android SDK, IOS SDK and other interfaces, and supports enterprise third-party application function integration.
2. Summarized by others
It has a comprehensive and constantly updated list of excellent project addresses. Go check it out when you have nothing to do, and you will receive a lot of goods!
If you don't start by studying the sample codes provided in the Android SDK, there may be no better way to master developing on the Android framework. The core development team of Android provides 15 excellent sample projects, including games, image processing, time display, start menu shortcuts, etc.
RemoteDroid is an Android application that allows users to use their own wireless network to operate their phones using a wireless keyboard and touch screen. This project provides developers with good examples of network connections, touch screen finger movements, etc.
The TorProxy application implements radio teletype communication (TOR) for Android phones and is used together with the Shadow application to anonymously surf the Internet using your mobile phone. From the source code of this project, you can master methods such as socket connection and cookie management.
SMSPopup can intercept text message content and display it in a bubble-shaped window. From this project you can learn how to use the built-in SMS interface.
The Standup Timer application is used to control the standing meeting time. It is similar to a stopwatch countdown and can remind everyone that the speaking time is up, thus ensuring that each participant uses the same time. From the code of this project, you can learn how to use the time function. In addition, the code of this project adopts the design idea of strict separation of view and model.
It is a client application of Foursquare.com. The application is mainly divided into two modules: API (com.joelapenna.foursquare) and interface front-end (com.joelapenna.foursquared). From the code of this project, you can learn how to synchronize, multi-thread, HTTP connection and other technologies.
Pedometer应用用于记录你每天走路步[]数的。尽管记录不一定精准，但是从这个项目中，可以学习几个不同的技术：加速器交互、语音更新、后台运行服 务等。
OpenSudoku是一个简单的九宫格数独游戏。从代码中可以学习到如何在视图中显示表格数据，以及如何和一个网站交互等技术。
ConnectBot是Android平台的一个客户端安全壳应用。从该项目代码中，可以学习到很多Android安全方面的内容，这些是你在开发应用 时经常需要考虑的安全问题。
当然在最后不能不提Wordpress的Android应用了，这是Wordpress官方开发团队提供的一个项目。从代码中可以学习到XMLRPC调 用（当然还有更多的优秀内容）。