本来我想从手机中拉出一个xml文件但是拉不出来 我重启了Android Device Monitor之后出现了 
我在谷歌搜索到这些 但是我看不明白 In a nutshell:
Ensure you have no other monitor.exe (if on Windows) or monitor (if OS X / Linux) process running. If you do, kill it.
Run rm -rf $HOME/.android/monitor-workspace or remove the directory manually
This did the trick for me: I was able to run DDMS without the Null Pointer Exception after following these steps.
小弟新手 求大神解决
