Language Level Java 8 (Retrolambda) on AndroidStudio 4+?

Question

So, someone backported Lambdas for Java 8 back to Java 6, and 7. Apparently it also works for Android. The project is called Retrolambda. I wanted to play around with this on AndroidStudio, but it seems in recent version they have removed the ability to set Java 8 as the Language Level (so I don't get compile errors while using Lambdas). Does anyone know a way around this? I imagine it'd have something to do with the fact that AndroidStudio is a modified IntelliJ. Any help would be appreciated.

Solution 1

It is removed on new project, but it is available in the properties after the project is created. Note that I haven't actually compiled with any new Java 8 features yet, so let's hope that works.

Right click on your project, go to Open Module Settings. I think there's a bug somewhere, as once I navigate away from those language settings tab, I can never get back to it.

To work around that, you can edit MyProject/.idea/misc.xml and look for the languageLevel attribute.

To enable Project settings once you navigate away, edit MyProject/.idea/workspace.xml and search for project.structure.last.edited. Set the value to "Project".

Solution 2

I've found that you can set the "language level" to Java 8 in Android Studio by modifying the build.gradle to include the following:

android {
  compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
  }
}

Comments

[spierce7]

I can't find the setting in the properties after the project is created. It looks like they removed it there too. Please give detailed instructions.

[spierce7]

That actually is what I was hoping for. Thanks!

[spierce7]

Update: This option has just been added back into the latest build of Android Studio.

[HolySamosa]

FYI: I'm seeing the same bug (?) with the General settings disappearing from the Module Settings screen.

[spierce7]

@HolySamosa you could try to just switch to IntelliJ. It's almost the exact same as Android Studio due to it being the base for Android Studio, and you can better control this type of stuff.

[Paul Verest]

very similar to java 7 tools.android.com/tech-docs/new-build-system/…

[IgorGanapolsky]

@joe My .idea/misc.xml already has languageLevel="JDK_1_8". Yet I am experiencing this error.

[Papipo]

What happens if I have a module which is not an android project? I can't use this solution there.

[Brent Aureli]

this worked, I can compile and run but android studio still flags the code as error(red underlined ect..) in the editor. Any suggestions?

[azwar_akbar]

Great solution. Thanks.

[Dino Tw]

Android does not support all Java 8 language features, developer.android.com/guide/platform/j8-jack.html