我发现了一个解决方案，为什么R.class不被Eclipse重新创建后- 2清洁，构建等。

问题在strings.xml中:

<string name="hello">Hello World, HelloAutoComplete!</string>

<string name="app_name">HelloAutoComplete</string>

这些是Eclipse在创建项目时默认创建的。

当然，您需要根据自己的需求更改strings.xml。有时你会清除字符串。xml这两行代码:

它在AndroidManifest.xml文件中产生了一个问题:

<application android:icon="@drawable/icon"  android:label="@string/app_name">
<activity android:name=".HelloAutoComplete" android:label="@string/app_name">

所以它不能与strings。xml通信。

确保你没有导入

android.R;

在Eclipse中，只需使用Project——> clean来清理项目。的 R.java将被自动(重新)创建。

如果由于某种原因，这不起作用:确保你的layout.xml文件不包含错误。Eclipse在这里似乎有点bug:有时它不会在XML或包资源管理器中标记错误。在这种情况下:在使用“clean”后查看“console”或“problems”视图。所有错误都应该显示在那里。修好它们，重新清理。

注意:没有必要修复因为缺少R文件而导致的错误!只需修复XML文件和其他项目错误，并使用清洁!

很明显，这个问题有很多原因。如果你在64位的linux机器上，你第一次设置ADT，你可能会遇到这个问题，R不能自动生成。检查控制台选项卡，你可能会看到类似的错误:

 'No such file or directory' while attempting to get adb version from '/home/patrick/code/android-sdks/platform-tools/adb'

如果是这种情况，你需要安装ia32-libs，使用如下代码:

 sudo apt-get install ia32-libs

详见:Android adb未找到

以下是对我有效而其他答案无效的答案:

创建新的Android应用程序项目， 从旧目录复制所有文件和文件夹(除了/gen)并替换! 在包资源管理器中刷新项目根目录。 如果还在，再清理一下! 完成了。希望这能有所帮助。

我发现这发生在我与一个破碎的布局和一切爆炸。放松，这就像你第一次学习编程时犯的错误一样，你忘记了一个分号，它就会产生100个错误。许多人惊慌失措，按下所有的按钮，使事情变得更糟。

解决方案

Make sure that anything the R. links to is not broken. Fix all errors in your XML files. If anything in the ADKs are broken, R will not regenerate. If you somehow hit something and created import android.R in your activity, remove it. Run Project -> Clean. This will delete and regenerate R and BuildConfig. Make sure Project -> Build Automatically is ticked. If not, build it manually via Menu -> Project -> Build Project . Wait a few seconds for the errors to disappear. If it doesn't work, delete everything inside the /gen/ folder If it still doesn't work, try right-clicking your project -> Android Tools -> Fix Project Properties. Check your *.properties files (in the root folder of your app folder) and make sure that the links in there are not broken. Right-click your project > properties > Android. Look at the Project Build Target and Library sections on the right side of the page. Your Build Target should match the target in your AndroidManifest.xml. So if it's set to target 17 in AndroidManifest, make sure that the Target Name is Android 4.2. If your Library has an X under the reference, remove and re-add the library until there's a green tick. This might happen if you've moved a few files and folders around.

如果R不能再生怎么办

这通常发生在XML文件损坏时。

Check errors inside your XML files, mainly within the /res/ folder Common places are /layout/ and /values/, especially if you've changed one of them recently Check AndroidManifest.xml. I find that often I change a string and forget to change the string name from AndroidManifest.xml. Check that Android SDK Build-tools is installed. Window -> Android SDK Manager -> Tools -> Android SDK Build-tools Make sure when you update the Android SDK Tools, you also update the Android SDK Platform-tools and Android ADK Build-tools. Build fails silently if they don't match. If you can't find the issue, right click /gen/ -> Restore from local history... -> tick R.java -> click Restore. Even if it doesn't solve the problem, it will clear out the extra errors to make the problem easier to find.