警告：Activity not started, its current task has been brought to the front

Android开发中，控制台（Console）输出警告信息：ActivityManager: Warning: Activity not started, its current task has been brought to the front
愿意可能是你的模拟器中还有东西在运行，也就是你要运行的activity已经有一个在模拟器中运行了。
不要以为你的模拟器退出到桌面了就没有东西在跑了。在你调试的时候异常关闭的程序有可能就有activity在运行。

解决方法project->clean。 Activity not started, its current task has been brought to the front的问题就可以了。