Can I enable multidex in Android debug build only?

Question

Dears, I read in many blog posts that multidex apps startup is slower than normal apps. My app uses a lot of libraries that exceed 64k methods so I use multidex. But when I use proguard in release build, the final apk becomes less than 64k methods

So My question is: Can I enable multidex in Android debug build only so I don't have runtime error? and disable multi dex in release build as I don't need it?

If yes, how ?

If No, Is Android smart enough to speedup startup as it should recognize that app didn't exceed 64k even if it is multi dex app ?

antonicg · Answer 1 · 2016-05-11T22:35:03.097

21

Yes, you can. When you declare your buildTypes include multidex only for debug:

buildTypes {
    release {
        multiDexEnabled false
    }
    debug {
        multiDexEnabled true
    }
}

edited May 11 '16 at 22:35

answered May 11 '16 at 22:29

antonicg

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1

But then you still have to (conditionally, based on the value of `BuildConfig.DEBUG`) call `MultiDex.install(this)` in code, right? – Konrad Morawski Jul 07 '17 at 13:23
2

@KonradMorawski not necessary for Android 5 and up I believe – Boy Jan 25 '18 at 08:34
You could omit `multiDexEnabled false` for `release`. – Mygod Feb 11 '18 at 11:08
@Mygod, yes you don't have to specify for release, default is false. – Prakash Nadar Dec 16 '18 at 21:41

score 9 · Answer 2 · answered May 11 '16 at 22:45

Instead of enabling multidex only for debug, you can change your min sdk version to 21 only for debug so gradle can speed up dexing with ART:

android {
    productFlavors {
        // Define separate dev and prod product flavors.
        dev {
            // dev utilizes minSDKVersion = 21 to allow the Android gradle plugin
            // to pre-dex each module and produce an APK that can be tested on
            // Android Lollipop without time consuming dex merging processes.
            minSdkVersion 21
        }
        prod {
            // The actual minSdkVersion for the application.
            minSdkVersion 14
        }
    }
          ...
    buildTypes {
        release {
            runProguard true
            proguardFiles getDefaultProguardFile('proguard-android.txt'),
                                                 'proguard-rules.pro'
        }
    }
}
dependencies {
  compile 'com.android.support:multidex:1.0.0'
}

http://developer.android.com/tools/building/multidex.html

This is no longer needed. Latest versions of tools detect the API level of the attached device/emulator and performs the necessary multidex. — Vairavan, Nov 13 '18 at 03:42
You can simplify this solution further by getting rid of the additional flavors. Instead, you can change the `minSdkVersion` setting directly in the `debug` block like done [in this answer](https://stackoverflow.com/a/57180249/1665966). — Johnson_145, Aug 27 '19 at 16:06

score 3 · Answer 3 · edited Jun 20 '20 at 09:12

3

suggested methods are not needed anymore as android studio became "smart enough". In fact, it will now give you a warning when you use minSdkVersion 21 (the old way) to speed up build time with dex:

You no longer need a dev mode to enable multi-dexing during development, and this can break API version checks less...

In the past, our documentation recommended creating a dev product flavor with has a minSdkVersion of 21, in order to enable multidexing to speed up builds significantly during development. That workaround is no longer necessary, and it has some serious downsides, such as breaking API access checking (since the true minSdkVersion is no longer known.) In recent versions of the IDE and the Gradle plugin, the IDE automatically passes the API level of the connected device used for deployment, and if that device is at least API 21, then multidexing is automatically turned on, meaning that you get the same speed benefits as the dev product flavor but without the downsides.

edited Jun 20 '20 at 09:12

Community

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answered Dec 11 '17 at 21:59

usernotnull

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Hi! Where did you find this quote? Thank you! – orospakr Jun 27 '18 at 17:47
@orospakr I think it was a warning message from Android Studio in the build file, that's where I got it from – usernotnull Jun 28 '18 at 19:06
I think the purpose of having multidex only in the debug build is that when the app exceeds the 65k method limit only the debug build will be affected (unless the app is really huge) because obfuscation and shrinking occurs in the release build. – devconsole Mar 18 '19 at 14:48

score 0 · Answer 4 · answered Mar 18 '19 at 14:19

Yes, it even works with the multidex support library for Android versions prior to Lollipop with a little trick.

First specify multiDexEnabled for the debug build in build.gradle:

buildTypes {
    ...
    debug {
        ...
        multiDexEnabled true
    }
}

Then create an AndroidManifest.xml file under src/debug.

src/debug/AndroidManifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          xmlns:tools="http://schemas.android.com/tools">

    <application
        android:name="android.support.multidex.MultiDexApplication"
        tools:replace="android:name"/>

</manifest>

That should do the trick. If your app uses a custom application class then you have to create a subclass of your application class and specify the name of that subclass in the manifest.

The application subclass should look like this:

public class MyDebugApplication extends MyApplication {
    @Override
    protected void attachBaseContext(Context base) {
        super.attachBaseContext(base);
        MultiDex.install(this);
    }
}

Can I enable multidex in Android debug build only?

4 Answers4

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