我是新手求教个问题。
很简单的helloworld程序，而且曾经运行成功过，可是某次emulator不大正常后。我全删了，然后重新搭建了android开发平台。代码和虚拟机都重新做的，结果就run as 没反应了。我到虚拟机里去看试验程序其实已经装好了，可以卸载，但是找不到在哪运行，而且本来不是应该自动运行的么？
这是Console反馈信息
[2014-02-21 14:19:31 - AndroidHelloWorld] ------------------------------
[2014-02-21 14:19:31 - AndroidHelloWorld] Android Launch!
[2014-02-21 14:19:31 - AndroidHelloWorld] adb is running normally.
[2014-02-21 14:19:31 - AndroidHelloWorld] No Launcher activity found!
[2014-02-21 14:19:31 - AndroidHelloWorld] The launch will only sync the application package on the device!
[2014-02-21 14:19:31 - AndroidHelloWorld] Performing sync
[2014-02-21 14:19:31 - AndroidHelloWorld] Automatic Target Mode: Preferred AVD 'A2.2' is not available. Launching new emulator.
[2014-02-21 14:19:31 - AndroidHelloWorld] Launching a new emulator with Virtual Device 'A2.2'
[2014-02-21 14:19:35 - Emulator] emulator: warning: opening audio input failed
[2014-02-21 14:19:35 - Emulator]
[2014-02-21 14:19:35 - AndroidHelloWorld] New emulator found: emulator-5554
[2014-02-21 14:19:35 - AndroidHelloWorld] Waiting for HOME ('android.process.acore') to be launched...
[2014-02-21 14:20:07 - AndroidHelloWorld] HOME is up on device 'emulator-5554'
[2014-02-21 14:20:07 - AndroidHelloWorld] Uploading AndroidHelloWorld.apk onto device 'emulator-5554'
[2014-02-21 14:20:07 - AndroidHelloWorld] Installing AndroidHelloWorld.apk...
[2014-02-21 14:20:19 - AndroidHelloWorld] Success!
[2014-02-21 14:20:19 - AndroidHelloWorld] \AndroidHelloWorld\bin\AndroidHelloWorld.apk installed on device
[2014-02-21 14:20:19 - AndroidHelloWorld] Done!
额，刚才找到原因了，当初建项目时没有建activity，后来自己补了一个，就出现这个问题了。为啥自己添加的不行？是需要还设置哪个地方吗？
