在 Android Studio 的 Gradle 项目中添加外部 JAR 文件

我在 Android Studio 中向我的 gradle 项目添加外部 JAR 时遇到了很糟糕的情况.我在这里问了一个类似的问题，但那些答案对我不起作用.

I'm having a terrible time adding an external JAR to my gradle project in Android Studio. I asked a similar question here but those answers haven't worked for me.

我创建了一个 libs 文件夹并在那里添加了我的 JAR:

I created a libs folder and added my JAR in there:

~/android/MyProject/libs $ pwd
/Users/me/android/MyProject/libs
~/android/MyProject/libs $ ls
TestFlightLib.jar

我在 build.gradle

dependencies {
    compile fileTree(dir: 'libs', include: '*.jar')
}

做完这一切后，我点击了Build ->重建 项目，但仍然不允许我添加 import com.testflightapp.lib.TestFlight

After doing all this I clicked Build -> Rebuild project but that still doesn't let me add import com.testflightapp.lib.TestFlight

我还尝试了第二种解决方案，即右键单击 TestFlightLib.jar 并将其添加为模块.这让我可以成功添加 import com.testflightapp.lib.TestFlight 但是当我 Run 项目时，我仍然收到错误:Gradle: error: package com.testflightapp.lib 不存在

I also tried the second solution of right clicking TestFlightLib.jar and adding it as a Module. This lets me add import com.testflightapp.lib.TestFlight successfully but when I Run the project I still get the error: Gradle: error: package com.testflightapp.lib does not exist

我做错了什么?

如何简单地将外部 JAR 添加到我的 gradle 项目中?

How can I simply add an external JAR to my gradle project?