Android development: logcat is invalid and ADB is invalid

Logcat is an extremely important tool, but sometimes it becomes invalid, for example, when you repeatedly plug in or use several machines together. In this case, ADB usually has a problem. There is a restart ADB option in the triangle drop-down menu in the upper-left corner of the ddms interface, but sometimes this is useless. In this case, you can open the task manager, then, kill all the ADB processes, and restart eclipse. At this time, it is generally enough, or execute restart ADB again.