背景
Flutterに、google_mobile_adsを導入するため、
flutter pub getを行い、ビルドしようとしたら発生。
ERROR:D8: Cannot fit requested classes in a single dex file (# methods: 79453 > 65536)
com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives:
The number of method references in a .dex file cannot exceed 64K.
Learn how to resolve this issue at https://developer.android.com/tools/building/multidex.html
at com.android.builder.dexing.D8DexArchiveMerger.getExceptionToRethrow(D8DexArchiveMerger.java:151)
at com.android.builder.dexing.D8DexArchiveMerger.mergeDexArchives(D8DexArchiveMerger.java:138)
at com.android.build.gradle.internal.tasks.DexMergingWorkAction.merge(DexMergingTask.kt:859)
at com.android.build.gradle.internal.tasks.DexMergingWorkAction.run(DexMergingTask.kt:805)
at com.android.build.gradle.internal.profile.ProfileAwareWorkAction.execute(ProfileAwareWorkAction.kt:74)
at org.gradle.workers.internal.DefaultWorkerServer.execute(DefaultWorkerServer.java:63)
at org.gradle.workers.internal.NoIsolationWorkerFactory$1$1.create(NoIsolationWorkerFactory.java:66)
at org.gradle.workers.internal.NoIsolationWorkerFactory$1$1.create(NoIsolationWorkerFactory.java:62)
at org.gradle.internal.classloader.ClassLoaderUtils.executeInClassloader(ClassLoaderUtils.java:100)
at org.gradle.workers.internal.NoIsolationWorkerFactory$1.lambda$execute$0(NoIsolationWorkerFactory.java:62)
at org.gradle.workers.internal.AbstractWorker$1.call(AbstractWorker.java:44)
at org.gradle.workers.internal.AbstractWorker$1.call(AbstractWorker.java:41)
at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:204)
at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:199)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:66)
at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:59)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:157)
at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59)
at org.gradle.internal.operations.DefaultBuildOperationRunner.call(DefaultBuildOperationRunner.java:53)
at org.gradle.internal.operations.DefaultBuildOperationExecutor.call(DefaultBuildOperationExecutor.java:73)
at org.gradle.workers.internal.AbstractWorker.executeWrappedInBuildOperation(AbstractWorker.java:41)
at org.gradle.workers.internal.NoIsolationWorkerFactory$1.execute(NoIsolationWorkerFactory.java:59)
at org.gradle.workers.internal.DefaultWorkerExecutor.lambda$submitWork$2(DefaultWorkerExecutor.java:205)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at org.gradle.internal.work.DefaultConditionalExecutionQueue$ExecutionRunner.runExecution(DefaultConditionalExecutionQueue.java:187)
at org.gradle.internal.work.DefaultConditionalExecutionQueue$ExecutionRunner.access$700(DefaultConditionalExecutionQueue.java:120)
at org.gradle.internal.work.DefaultConditionalExecutionQueue$ExecutionRunner$1.run(DefaultConditionalExecutionQueue.java:162)
at org.gradle.internal.Factories$1.create(Factories.java:31)
at org.gradle.internal.work.DefaultWorkerLeaseService.withLocks(DefaultWorkerLeaseService.java:249)
at org.gradle.internal.work.DefaultWorkerLeaseService.runAsWorkerThread(DefaultWorkerLeaseService.java:109)
at org.gradle.internal.work.DefaultWorkerLeaseService.runAsWorkerThread(DefaultWorkerLeaseService.java:114)
at org.gradle.internal.work.DefaultConditionalExecutionQueue$ExecutionRunner.runBatch(DefaultConditionalExecutionQueue.java:157)
at org.gradle.internal.work.DefaultConditionalExecutionQueue$ExecutionRunner.run(DefaultConditionalExecutionQueue.java:126)
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64)
at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:48)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:829)
Caused by: com.android.tools.r8.CompilationFailedException: Compilation failed to complete, position: null
at Version.fakeStackEntry(Version_3.2.47.java:0)
at com.android.tools.r8.internal.ci.a(R8_3.2.47_ebadcf1df6fbed6005a238b8399b2cd411e753b60758261060e399f9498872a5:68)
at com.android.tools.r8.internal.ci.a(R8_3.2.47_ebadcf1df6fbed6005a238b8399b2cd411e753b60758261060e399f9498872a5:28)
at com.android.tools.r8.internal.ci.a(R8_3.2.47_ebadcf1df6fbed6005a238b8399b2cd411e753b60758261060e399f9498872a5:27)
at com.android.tools.r8.internal.ci.b(R8_3.2.47_ebadcf1df6fbed6005a238b8399b2cd411e753b60758261060e399f9498872a5:3)
at com.android.tools.r8.D8.run(R8_3.2.47_ebadcf1df6fbed6005a238b8399b2cd411e753b60758261060e399f9498872a5:11)
at com.android.builder.dexing.D8DexArchiveMerger.mergeDexArchives(D8DexArchiveMerger.java:136)
... 38 more
Caused by: com.android.tools.r8.internal.a: Cannot fit requested classes in a single dex file (# methods: 79453 > 65536)
at com.android.tools.r8.internal.tQ.a(R8_3.2.47_ebadcf1df6fbed6005a238b8399b2cd411e753b60758261060e399f9498872a5:14)
at com.android.tools.r8.internal.tQ.a(R8_3.2.47_ebadcf1df6fbed6005a238b8399b2cd411e753b60758261060e399f9498872a5:22)
at com.android.tools.r8.internal.fZ.a(R8_3.2.47_ebadcf1df6fbed6005a238b8399b2cd411e753b60758261060e399f9498872a5:560)
at com.android.tools.r8.internal.bZ.a(R8_3.2.47_ebadcf1df6fbed6005a238b8399b2cd411e753b60758261060e399f9498872a5:7)
at com.android.tools.r8.internal.o2.a(R8_3.2.47_ebadcf1df6fbed6005a238b8399b2cd411e753b60758261060e399f9498872a5:383)
at com.android.tools.r8.internal.o2.c(R8_3.2.47_ebadcf1df6fbed6005a238b8399b2cd411e753b60758261060e399f9498872a5:54)
at com.android.tools.r8.D8.d(R8_3.2.47_ebadcf1df6fbed6005a238b8399b2cd411e753b60758261060e399f9498872a5:763)
at com.android.tools.r8.D8.b(R8_3.2.47_ebadcf1df6fbed6005a238b8399b2cd411e753b60758261060e399f9498872a5:1)
at com.android.tools.r8.internal.ci.a(R8_3.2.47_ebadcf1df6fbed6005a238b8399b2cd411e753b60758261060e399f9498872a5:24)
... 41 more
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':app:mergeExtDexDebug'.
> A failure occurred while executing com.android.build.gradle.internal.tasks.DexMergingTaskDelegate
> There was a failure while executing work items
> A failure occurred while executing com.android.build.gradle.internal.tasks.DexMergingWorkAction
> com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives:
The number of method references in a .dex file cannot exceed 64K.
Learn how to resolve this issue at https://developer.android.com/tools/building/multidex.html
* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.
* Get more help at https://help.gradle.org
BUILD FAILED in 19s
[!] App requires Multidex support
Multidex support is required for your android app to build since the number of methods has exceeded 64k. See https://docs.flutter.dev/deployment/android#enabling-multidex-support for more information. You may pass the --no-multidex flag to skip Flutter's multidex support to use a manual solution.
Flutter tool can add multidex support. The following file will be added by flutter:
android/app/src/main/java/io/flutter/app/FlutterMultiDexApplication.java
cannot prompt without a terminal ui
Exception: Gradle task assembleDebug failed with exit code 1
ERROR:D8: Cannot fit requested classes in a single dex file (# methods: 68010 > 65536)
com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives:
The number of method references in a .dex file cannot exceed 64K.
原因
Androidアプリは、ビルドシステムの都合により、メソッド数が65536（64k=64☓1024）を超えるとビルドできないという制約があり、「64k問題」と呼ばれるものが原因だそうです。
解決方法
android/app/build.gradleを編集します。
「multiDexEnabled true」以下のように追加します。
android {
defaultConfig {
applicationId ""
:
//追加する
multiDexEnabled true
}
:
}