How to avoid DEX 64K LIMIT by importing the right library

问题

I had this issue where I overflow the 64k method limit in Dalvik when compiling all the library I used. I started to have this issue when I imported the Support Library, as some are already contained in others, it ended up overflowing the limit.

Is there a way to verify if a library is unused in the current project or already imported through another library dependencies?

Currently, I'm excluding those I know for sure but it seems weird to have to do this by hand.

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:multidex:1.0.1'
    compile "com.android.support:percent:${supportLibVersion}"
    compile("com.android.support:design:${supportLibVersion}") {
        exclude module: 'support-v4'
    }
    compile("com.android.support:cardview-v7:${supportLibVersion}") {
        exclude module: 'support-v4'
    }

    compile('com.github.nkzawa:socket.io-client:0.4.1') {
        exclude group: 'org.json', module: 'json'
    }
    compile('com.astuetz:pagerslidingtabstrip:1.0.1') {
        exclude module: 'support-v4'
    }
//...
}

Solutions so far:

Use a Gradle plugin – We wrote an extremely easy to use Gradle plugin some time back that lists the number of methods by package along with the total number. You can find more information about it here.
www.methodscount.com – Wondering how many methods a particular library will add to your application? Just enter the ‘compile’ statement on this website and it’ll tell you it’s method count, dependencies, JAR size and DEX size.
Android Studio Plugin – This excellent plugin shows the method count of each dependency right inside Android Studio.
Using the MultiDex Support Library If you are using Android Studio, the process is very straight-forward. If you are not, I highly recommend migrating, as Google may soon drop support for the Eclipse ADT plugin and the old Ant based build system.

Step 1

Add the dependency for the MultiDex support library in your build.gradle

dependencies { 
... 
   compile 'com.android.support:multidex:' 
   ... 
}

Step 2

Enable multi-dexing by setting the multiDexEnabled flag in the buildType or productFlavor section of your gradle configuration.

defaultConfig { 
   ... 
multiDexEnabled true 
... 
}

Now depending on your project, you have 3 options:

If you haven’t created your own Application class, simply declare android.support.multidex.MultiDexApplication as your application class in AndroidManifest.xml

   .... 
   android:name="android.support.multidex.MultiDexApplication" 
   ...

If you already have your own Application class, make it extend android.support.multidex.MultiDexApplication instead of android.app.Application

If your Application class is extending some other class and you don’t want to or can’t change it, override attachBaseContext() as shown below:

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

回答1:

You can open the terminal and run command gradlew app:dependencies to test which dependencies are already included in the others as transitive dependencies for your project along with the respective versions of each.

For example I got the following dependency chart for one of my projects for the com.android.support:design library I used:

+--- com.android.support:design:23.3.0
|    +--- com.android.support:appcompat-v7:23.3.0
|    |    +--- com.android.support:support-vector-drawable:23.3.0
|    |    |    \--- com.android.support:support-v4:23.3.0
|    |    |         \--- com.android.support:support-annotations:23.3.0
|    |    +--- com.android.support:animated-vector-drawable:23.3.0
|    |    |    \--- com.android.support:support-vector-drawable:23.3.0 (*)
|    |    \--- com.android.support:support-v4:23.3.0 (*)
|    +--- com.android.support:support-v4:23.3.0 (*)
|    \--- com.android.support:recyclerview-v7:23.3.0
|         +--- com.android.support:support-v4:23.3.0 (*)
|         \--- com.android.support:support-annotations:23.3.0

回答2:

hey you can try my trick, it might be useful for you

First of all you should avoid external libraries. Like in that libraries have same dependencies. So, try to merge that library with android application code. Due to this save much space for methods.
Use useful dependencies and libraries like if you want google play services then include only useful services not all.See example
```
compile "com.google.android.gms:play-services-location:9.4.0"
compile "com.google.android.gms:play-services-maps:9.4.0" 
```

Avoid this

compile 'com.google.android.gms:play-services:9.4.0'

Remove unwanted dependencies.Use very chooseable dependencies in your code.
If all things not work really well then use multidex in your code.But it create Multiple dex files.So, your code will take much time for compilation.

Thanks hope this will help you.

回答3:

 defaultConfig
 {    
     multiDexEnabled true 
 }

 dependencies {
     compile 'com.android.support:multidex:1.0.0'
 }

and also add this method into your application class

@Override
protected void attachBaseContext(Context newBase) {

    super.attachBaseContext(newBase);

    MultiDex.install(this);
}

回答4:

Click On File Then Click On Project Structure Click On app on the left bottom of the popup. You will see multiple Tabs click on Dependencies Tab Then Click On plus at right top chose Library dependency search your desire Library it will show Those Libraries which are available in your IDE

回答5:

Though using Multidex Support Library library solves the problem, it is not perfect. The first thing to do should be to determine how many methods your app currently has and how many of them are being added by each of its dependencies. Earlier you had to do this manually, but now there are a bunch of tools available:

Use a Gradle plugin – This is an extremely easy to use Gradle plugin some time back that lists the number of methods by package along with the total number. You can find more information about it here.
www.methodscount.com – Just enter the ‘compile’ statement on this website and it’ll tell you it’s method count, dependencies, JAR size and DEX size.
Android Studio Plugin – This excellent plugin shows the method count of each dependency right inside Android Studio.

Irrespective of what you tool you end up using, use the information it provides to perform an audit of your app’s dependencies. You should look for unused libraries or ones that can be minimized or even replaced with your own simpler solution. If you are not using Proguard to remove unused code, first enable it and see if it solves the problem(Check this). Using Proguard is well… not fun, but once you manage to make it work properly, it’ll significantly reduce the method count. If all else fails, you’ll have to use the MultiDex support library.

Check out gradle task to strip unused packages on Google Play Services library.

Conclusion

While the Multidex Support Library fixes the DEX 64K problem in most cases, it should be treated as a last resort. Before attempting to use it, you should audit your project for unwanted dependencies and remove as much unused code as possible using ProGuard. If you do go ahead and use it, make sure you test your app on older devices.

Hope this will help you.

来源：https://stackoverflow.com/questions/37191869/how-to-avoid-dex-64k-limit-by-importing-the-right-library

标签

android

gradle

android-support-library

android-appcompat

android-multidex