Default interface methods are only supported starting with Android N

Question

I upgraded to android studio 3.1 and I\'m getting the following error:

Default interface methods are only supported starting with Android N (--min-api 24): vo         


        

Answer 1

In app-level gradle, you have to write these code:

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

They come from JavaVersion.java in Android.

An enumeration of Java versions.

Before 9: http://www.oracle.com/technetwork/java/javase/versioning-naming-139433.html

After 9: http://openjdk.java.net/jeps/223

@canerkaseler

Answer 2

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'


android {
compileSdkVersion 30
buildToolsVersion "30.0.0"

compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
}

defaultConfig {
    applicationId "com.example.architecture"
    minSdkVersion 16
    targetSdkVersion 30
    versionCode 1
    versionName "1.0"

    testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}
 buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
    }
   }
}
dependencies {

implementation 'androidx.room:room-runtime:2.2.5'
implementation 'androidx.lifecycle:lifecycle-extensions:2.2.0'
annotationProcessor 'androidx.room:room-compiler:2.2.5'
def lifecycle_version = "2.2.0"
def arch_version = "2.1.0"

implementation fileTree(dir: "libs", include: ["*.jar"])
implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
implementation 'androidx.core:core-ktx:1.3.0'
implementation 'androidx.appcompat:appcompat:1.1.0'
implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'androidx.test.ext:junit:1.1.1'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
implementation "androidx.lifecycle:lifecycle-viewmodel-savedstate:$lifecycle_version"
implementation "androidx.lifecycle:lifecycle-common-java8:$lifecycle_version"
implementation "androidx.lifecycle:lifecycle-service:$lifecycle_version"
implementation "androidx.lifecycle:lifecycle-process:$lifecycle_version"
implementation "androidx.cardview:cardview:1.0.0"
}

---

Add the configuration in your app module's build.gradle

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

Answer 3

My project use ButterKnife and Retro lambda, setting JavaVersion.VERSION_1_8 will not work. It always blames at ButterKnife static interface function until I found this Migrate from Retrolambda

TL;DR

Just add JavaVersion.VERSION_1_8 and completely REMOVE retrolambda from your project. It will build successfully.

Answer 4

You can resolve this issue by downgrading Source Compatibility and Target Compatibility Java Version to 1.8 in Latest Android Studio Version 3.4.1

1. Open Module Settings (Project Structure) Winodw by right clicking on app folder or Command + Down Arrow on Mac

2. Go to Modules -> Properties

3. Change Source Compatibility and Target Compatibility Version to 1.8

4. Click on Apply or OK Thats it. It will solve your issue.

Also you can manually add in build.gradle (Module: app)

android {
...

compileOptions {
        sourceCompatibility = '1.8'
        targetCompatibility = '1.8'
    }

...
}

Answer 5

Setting the minSdkVersion to 21 from 19 solved the issue for me.

defaultConfig {
        applicationId "com.example"
        minSdkVersion 21
        targetSdkVersion 29
        versionCode 23
        versionName "1.0"
        vectorDrawables.useSupportLibrary = true
    }

Answer 6

Use this code in your build.gradle

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