android - Android Studio中的“无法解析符号R”(“cannot resolve symbol R” in Android Studio)

Question

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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".

(在我引用R.id.something所有类的所有实例中， R均为红色，并显示“无法解析符号R”。)

Also every time there is R.layout.something it is underlined in red and says "cannot resolve method setContentView(?)".

(同样，每次有R.layout.something它都会用红色下划线表示“无法解析方法setContentView（？）”。)

The project always builds fine.

(该项目始终可以正常运行。)

It is annoying to see this all the time.

(一直看到这很烦人。)

I have read many other questions on here about something similar but most involved importing projects from Eclipse.

(我在这里阅读了许多其他问题，这些问题与相似但最涉及从Eclipse导入项目有关。)

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.

(我使用的是我认为是Android Studio的最新版本，并且该项目是使用Android Studio创建的，并且可以正常工作而没有任何“无法解决R”问题。)

I would like to know what causes this if anyone knows.

(如果有人知道，我想知道是什么原因造成的。)

  ask by ez4nick translate from so

Answer 1

I had this this issue too.

(我也有这个问题。)

A simple 'gradlew clean' and 'gradlew build' did the trick.

(一个简单的“ gradlew clean”和“ gradlew build”就可以解决问题。)

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Click on Build->Clean Project and that will perform a gradle clean

(点击Build- > Clean Project ，这将执行gradle clean)