(Introduction: Android development will bring a new round of craze. Many developers have invested in this wave and created many appropriate and excellent uses. In the meantime, many developers have offered to use open source projects, contributing their talents and creativity. Learning open source code is the best way to master technology. The following are some open source projects recommended. These projects not only provide excellent ideas, but also can directly master the use of the interface of the Android kernel: 1. If the sample projects provided by the Android team were not proposed from learning the Android SDK)