Lambda expressions in android

Question

How use lambda expressions in android? For example, I compile this code in IntelliJ IDEA:

package com.example.myapp;

import android.app.Activity;
import android.app.AlertDialog;
import android.os.Bundle;

public class MyActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        test s = () -> {return "Lambda expressions test";};
        AlertDialog alertDialog = new AlertDialog.Builder(this)
                .setTitle("Lambda expression")
                .setMessage(s.t())
                .create();
        alertDialog.show();
    }
}
interface test {
    public String t();
}

But have this erorrs:

Information:Using javac 1.8.0_05 to compile java sources
Information:36 errors
Information:0 warnings
Information:Compilation completed with 36 errors and 0 warnings in 29 sec
Error:Android Dex: [myappі] UNEXPECTED TOP-LEVEL EXCEPTION:
Error:Android Dex: [myappі] com.android.dx.cf.iface.ParseException: InvokeDynamic not supported

How to set up so you can use lambda expressions?

android supports java 6/7 not 8 i guess. lambda is introduced in java 8 i guess — Raghunandan, Jun 13 '14 at 18:03
yes, lambda is introduced in java 8, but what can I do if there is already a lot of code is written with a lambda expression — user3430722, Jun 13 '14 at 18:17
@Raghunandan You are wrong. Lambdas work easily in Android Studio if you set your build.gradle to use Java 8. — IgorGanapolsky, Feb 16 '15 at 20:37
possible duplicate of http://stackoverflow.com/questions/23318109/is-it-possible-to-use-java-8-for-android-development — Sufiyan Ghori, Feb 16 '15 at 20:41
@IgorGanapolsky i am not sure i haven't tried it. i din't know about retrolambda when i commented. I found nothing in the docs — Raghunandan, Feb 17 '15 at 12:41

score 7 · Accepted Answer · answered Jun 13 '14 at 18:17

7

Android only supports java 6 and 7. You can use plugins to get lambdas though such as https://github.com/evant/gradle-retrolambda.

answered Jun 13 '14 at 18:17

Pieces

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1

It's supporting java 8 now! – Mahdi Moqadasi Dec 23 '18 at 12:33

score 3 · Answer 2 · answered Feb 16 '15 at 20:39

In your build.gradle add this:

compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
}

Assuming you installed Java 8 on your machine!

Also, add this:

dependencies {
    classpath 'com.android.tools.build:gradle:1.0.0'
    classpath 'me.tatarka:gradle-retrolambda:2.5.0'
}

And finally:

apply plugin: 'me.tatarka.retrolambda'

Oussaki · Answer 3 · 2017-06-01T06:13:22.463

Java 8 language features are now supported by the Android build system

Yesterday, we released Android Studio 2.4 Preview 6. Java 8 language features are now supported by the Android build system in the javac/dx compilation path. Android Studio's Gradle plugin now desugars Java 8 class files to Java 7-compatible class files, so you can use lambdas, method references and other features of Java 8.

Source : https://android-developers.googleblog.com/2017/04/java-8-language-features-support-update.html

Edit: 06/01/2017

Lambda Expressions now supported in Android Studio 3.0

Lambda expressions in android

3 Answers3