AndroidStudio说“无法解析符号”但项目编译-AndroidStudiosays“cannotresolvesymbol”butprojectcompiles

207  

No idea if this will work or not but my only thought so far: right click the jar file in file tree within AS and select "Add as library..."

不知道这是否有效但是到目前为止我唯一的想法：右键单击AS中文件树中的jar文件，然后选择“Add as library ...”

EDIT: You can do "File" -> "Invalidate Caches...", and select "Invalidate and Restart" option to fix this.

编辑：您可以执行“文件” - >“无效缓存...”，并选择“无效并重新启动”选项来解决此问题。

EDIT 2: This fix should work for all similar incidents and is not a twitter4j specific resolution.

编辑2：此修复程序应适用于所有类似的事件，而不是twitter4j特定的解决方案。

26  

Try changing the order of dependencies in File > Project Structure > (select your project) > Dependencies.

尝试在“文件”>“项目结构”>（选择项目）>“依赖项”中更改依赖项的顺序。

Invalidate Caches didn't work for me, but moving my build from the bottom of the list to the top did.

Invalidate Caches对我不起作用，但将我的构建从列表底部移到顶部。

9  

This is what worked for me.

这对我有用。

In the Project panel, right click on the project name, and select Open Module Settings from the popup menu.

在“项目”面板中，右键单击项目名称，然后从弹出菜单中选择“打开模块设置”。

then change the Compile SDK Version to the minimum version available (the minimum sdk version you set in the project). wait for android studio to load everything.

然后将Compile SDK Version更改为可用的最低版本（您在项目中设置的最小sdk版本）。等待android studio加载所有内容。

It will give you some errors, ignore those.

它会给你一些错误，忽略它们。

Now go to your java file and android studio will suggest you import

现在转到你的java文件，android studio会建议你导入

import android.support.v4.app.FragmentActivity;

import android.support.v4.app.FragmentActivity;

Import it, then go back to Open Module Settings and change the compile sdk version back to what it was before.

导入它，然后返回打开模块设置并将编译sdk版本更改回之前的版本。

Wait for things to load and voila.

等待东西加载瞧。

7  

For mine was caused by the imported library project, type something in build.gradle and delete it again and press sync now, the error gone.

因为我的是由导入的库项目引起的，在build.gradle中键入内容并再次删除它并立即按下同步，错误消失了。

3  

When i lived to this problem(red color codes but they work correctly) in my project;

当我在我的项目中遇到这个问题（红色代码，但它们正常工作）;

As first, i made it that (File -> Indicate Cashes) --> (Invalidate and Restart).

首先，我做到了（文件 - >指示兑现） - >（无效和重启）。

As last, i resync my build.gradle file in my app. After problem was resolved.

最后，我在我的应用程序中重新同步我的build.gradle文件。问题解决后。

3  

I also had this issue with my Android app depending on some of my own Android libraries (using Android Studio 3.0 and 3.1.1).

我的Android应用程序也遇到了这个问题，这取决于我自己的一些Android库（使用Android Studio 3.0和3.1.1）。

Whenever I updated a lib and go back to the app, triggering a Gradle Sync, Android Studio was not able to detect the code changes I made to the lib. Compilation worked fine, but Android Studio showed red error lines on some code using the lib.

每当我更新lib并返回应用程序，触发Gradle Sync时，Android Studio都无法检测到我对lib所做的代码更改。编译工作正常，但Android Studio在使用lib的某些代码上显示红色错误行。

After investigating, I found that it's because gradle keeps pointing to an old compiled version of my libs. If you go to yourProject/.idea/libraries/ you'll see a list of xml files that contains the link to the compiled version of your libs. These files starts with Gradle__artifacts_*.xml (where * is the name of your libs).

在调查之后，我发现这是因为gradle一直指向我的libs的旧编译版本。如果你转到yourProject / .idea / libraries /，你会看到一个xml文件列表，其中包含libs编译版本的链接。这些文件以Gradle__artifacts _ * .xml（其中*是libs的名称）开头。

So in order for Android Studio to take the latest version of your libs, you need to delete these Gradle__artifacts_*.xml files, and Android Studio will regenerate them, pointing to the latest compiled version of your libs.

因此，为了让Android Studio获取最新版本的库，您需要删除这些Gradle__artifacts _ *。xml文件，Android Studio将重新生成它们，指向您的库的最新编译版本。

If you don't want to do that manually every time you click on "Gradle sync" (who would want to do that...), you can add this small gradle task in the build.gradle file of your app.

如果您不希望每次单击“Gradle sync”（谁想要这样做......）时手动执行此操作，您可以在应用程序的build.gradle文件中添加此小gradle任务。

task deleteArtifacts {
    doFirst {
        File librariesFolderPath = file(getProjectDir().absolutePath + "/../.idea/libraries/")
        File[] files = librariesFolderPath.listFiles({ File file -> file.name.startsWith("Gradle__artifacts_") } as FileFilter)

        for (int i = 0; i