Android Studio升级到2.0,运行程序出现Session ‘app’: Error Launching activity,不能编译运行程序,发现是由于2.0的新特性“instant run”,个人解决办法是关闭这个功能,在File->Settings->Build, Execution,Deployment找到Instant Run,把打钩的选项都去掉,apply就能够了app