“无法解析符号R”在Android Studio

In every instance in all of my classes where I reference R.id.something, the R is in red and it says "cannot resolve symbol R". Also every time there is R.layout.something it is underlined in red and says "cannot resolve method setContentView(?)". The project always builds fine. It is annoying to see this all the time. I have read many other questions on here about something similar but most involved importing projects from Eclipse. I am using what I believe to be the most recent version of Android Studio and the project was created with Android Studio and worked without any "cannot resolve R" problems. I would like to know what causes this if anyone knows.

当前回答

请看下面的图片去文件->项目设置->设置所有设置像图像和同步它将把所有最新的设置在你的项目。如果您的项目导入成功，那么您必须这样做。因为它会导入所有的更新设置和gradle。

2019-03-22 05:08:43

其他回答

我在androidmanifest中有android:textAllCaps = "false"，这对R文件造成了严重破坏。我删除了，一切正常。我认为目标sdk设置得不够高。

2015-09-02 22:10:40

我在清理建筑。Gradle和这个错误出现。

一大堆“清理和重建”的答案。这些对我都没用。

最后，我发现我无意中复制粘贴了build.gradle中错误的“命名空间”名称。修复了它，它运行。

2023-02-07 09:41:17

在最新版本的Android Studio中，至少对我来说，如下作品:

“工具”->“Android”->“同步项目与Gradle文件”