Java android studio找不到“活动”符号
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android studio cannot find "Activity" symbol
提问by Elad Benda
I have tried to create and run hello worldnew app using Android studio.however i cannot compile as it says it's cannot resolve Activitysymbol.
我尝试使用创建和运行hello world新应用程序，Android studio.但是我无法编译，因为它说它无法解析Activity符号。
and also other basic symbols in the black template.
以及黑色模板中的其他基本符号。
I suggest adding/configuration the JDK.
我建议添加/配置 JDK。
I guess I'm doing this wrong, because I have tried to add the JDKand the problem re-occurred.
我想我做错了，因为我试图添加JDK和问题再次发生。
how to solve this?
如何解决这个问题？
UPDATE1
更新1
couldn't find external build
找不到外部构建
Android studio 0.2.6
安卓工作室 0.2.6
回答by slund
I ran into this problem as well and it was driving me crazy. Here is what worked for me:
我也遇到了这个问题，这让我发疯了。这是对我有用的：
I noticed that Under File|Project Structure the Classpath for my selected android SDK (Android 4.3 Google APIs) was blank.
我注意到在 File|Project Structure 下，我选择的 android SDK（Android 4.3 Google API）的类路径是空白的。
I changed the Build target to a different SDK, then switched back and the Classpath tab became properly populated. Once I did that, android symbols were resolved in my project.
我将 Build 目标更改为不同的 SDK，然后切换回来并且 Classpath 选项卡正确填充。一旦我这样做了，android 符号就在我的项目中得到了解决。
If you don't see pathtosdk/android-##/android.jar listed in the classpath, this could be your solution.
如果您没有在类路径中看到 pathtosdk/android-##/android.jar，这可能是您的解决方案。
回答by Manoj Behera
Android Studio
安卓工作室
File -> Invalidate Caches / Restart
文件 -> 使缓存无效/重新启动
It Worked for me.
它对我有用。
回答by Justin Russo
Make sure to import android.app.Activity.
确保导入 android.app.Activity。
import android.app.Activity;
