Android Gradle Build Plugin 4.0.0 & R8 Desugaring 不适用于 API 19

Question

我正在将 Android 应用程序从使用 Proguard 的脱糖切换到 Android Gradle Build Plugin 4.0.0 中可用的新 R8 脱糖。
我已经按照详细的步骤 in the official documentation启用 Java 8 库脱糖:
gradle.properties

projectJavaVersion = 1.8
android.useAndroidX=true
android.enableJetifier=true

应用程序构建.gradle

plugins {
    id 'com.android.application'
    id 'kotlin-android'
}
android {
    buildToolsVersion '29.0.2'
    compileSdkVersion 29
    compileOptions {
        coreLibraryDesugaringEnabled true
        sourceCompatibility projectJavaVersion
        targetCompatibility projectJavaVersion
    }
    kotlinOptions {
        jvmTarget = projectJavaVersion
    }
    defaultConfig {
        multiDexEnabled true
        minSdkVersion 19
        targetSdkVersion 23
        applicationId = 'com.example.app'
    }
    buildTypes {
        release {
            ...
            minifyEnabled true
        }
        debug {
            debuggable true
            minifyEnabled true
        }
    }
}
dependencies {
    coreLibraryDesugaring "com.android.tools:desugar_jdk_libs:1.0.10"
    ...
}

您可以看到我们至少支持 API 19。没有构建错误(使用 Gradle 6.1.1)，但有以下警告:

Warning in synthesized for lambda desugaring:
  Type `j$.$r8$wrapper$java$util$function$Function$-V-WRP` was not found, it is required for default or static interface methods desugaring of `java.util.Comparator java.time.chrono.-$$Lambda$AbstractChronology$j22w8kHhJoqCd56hhLQK1G0VLFw.thenComparing($-vivified-$.java.util.function.Function)`
Warning in synthesized for lambda desugaring:
  Type `j$.$r8$wrapper$java$util$function$ToLongFunction$-V-WRP` was not found, it is required for default or static interface methods desugaring of `java.util.Comparator java.time.chrono.-$$Lambda$AbstractChronology$j22w8kHhJoqCd56hhLQK1G0VLFw.thenComparingLong($-vivified-$.java.util.function.ToLongFunction)`
Warning in synthesized for lambda desugaring:
  Type `j$.$r8$wrapper$java$util$function$ToDoubleFunction$-V-WRP` was not found, it is required for default or static interface methods desugaring of `java.util.Comparator java.time.chrono.-$$Lambda$AbstractChronology$j22w8kHhJoqCd56hhLQK1G0VLFw.thenComparingDouble($-vivified-$.java.util.function.ToDoubleFunction)`
Warning in synthesized for lambda desugaring:
  Type `j$.$r8$wrapper$java$util$function$ToIntFunction$-V-WRP` was not found, it is required for default or static interface methods desugaring of `java.util.Comparator java.time.chrono.-$$Lambda$AbstractChronology$j22w8kHhJoqCd56hhLQK1G0VLFw.thenComparingInt($-vivified-$.java.util.function.ToIntFunction)`
Warning in /Users/username/.gradle/caches/modules-2/files-2.1/com.android.tools/desugar_jdk_libs/1.0.4/961afbdb3d41eebfb63b8c8ccdc97453b869964e/desugar_jdk_libs-1.0.4.jar:java/util/concurrent/ConcurrentHashMap$EntryIterator.class:
  Type `j$.$r8$wrapper$java$util$function$Consumer$-V-WRP` was not found, it is required for default or static interface methods desugaring of `void java.util.concurrent.ConcurrentHashMap$EntryIterator.forEachRemaining($-vivified-$.java.util.function.Consumer)`
Warning in /Users/username/.gradle/caches/modules-2/files-2.1/com.android.tools/desugar_jdk_libs/1.0.4/961afbdb3d41eebfb63b8c8ccdc97453b869964e/desugar_jdk_libs-1.0.4.jar:java/util/concurrent/ConcurrentHashMap$CollectionView.class:
  Type `j$.$r8$wrapper$java$util$stream$Stream$-WRP` was not found, it is required for default or static interface methods desugaring of `$-vivified-$.java.util.stream.Stream java.util.concurrent.ConcurrentHashMap$CollectionView.parallelStream()`
Warning in /Users/username/.gradle/caches/modules-2/files-2.1/com.android.tools/desugar_jdk_libs/1.0.4/961afbdb3d41eebfb63b8c8ccdc97453b869964e/desugar_jdk_libs-1.0.4.jar:java/util/concurrent/ConcurrentHashMap$CollectionView.class:
  Type `j$.$r8$wrapper$java$util$Spliterator$-WRP` was not found, it is required for default or static interface methods desugaring of `$-vivified-$.java.util.Spliterator java.util.concurrent.ConcurrentHashMap$CollectionView.spliterator()`
Warning in /Users/username/.gradle/caches/modules-2/files-2.1/com.android.tools/desugar_jdk_libs/1.0.4/961afbdb3d41eebfb63b8c8ccdc97453b869964e/desugar_jdk_libs-1.0.4.jar:java/util/concurrent/ConcurrentHashMap$CollectionView.class:
  Type `j$.$r8$wrapper$java$util$function$Predicate$-V-WRP` was not found, it is required for default or static interface methods desugaring of `boolean java.util.concurrent.ConcurrentHashMap$CollectionView.removeIf($-vivified-$.java.util.function.Predicate)`
Warning in /Users/username/.gradle/caches/modules-2/files-2.1/com.android.tools/desugar_jdk_libs/1.0.4/961afbdb3d41eebfb63b8c8ccdc97453b869964e/desugar_jdk_libs-1.0.4.jar:java/util/DesugarCollections$SynchronizedMap.class:
  Type `j$.$r8$wrapper$java$util$function$BiFunction$-V-WRP` was not found, it is required for default or static interface methods desugaring of `void java.util.DesugarCollections$SynchronizedMap.replaceAll($-vivified-$.java.util.function.BiFunction)`
Warning in /Users/username/.gradle/caches/modules-2/files-2.1/com.android.tools/desugar_jdk_libs/1.0.4/961afbdb3d41eebfb63b8c8ccdc97453b869964e/desugar_jdk_libs-1.0.4.jar:java/util/DesugarCollections$SynchronizedMap.class:
  Type `j$.$r8$wrapper$java$util$function$BiConsumer$-V-WRP` was not found, it is required for default or static interface methods desugaring of `void java.util.DesugarCollections$SynchronizedMap.forEach($-vivified-$.java.util.function.BiConsumer)`
Warning in /Users/username/.gradle/caches/modules-2/files-2.1/com.android.tools/desugar_jdk_libs/1.0.4/961afbdb3d41eebfb63b8c8ccdc97453b869964e/desugar_jdk_libs-1.0.4.jar:java/util/concurrent/ThreadLocalRandom.class:
  Type `j$.$r8$wrapper$java$util$stream$IntStream$-WRP` was not found, it is required for default or static interface methods desugaring of `$-vivified-$.java.util.stream.IntStream java.util.concurrent.ThreadLocalRandom.ints()`
Warning in /Users/username/.gradle/caches/modules-2/files-2.1/com.android.tools/desugar_jdk_libs/1.0.4/961afbdb3d41eebfb63b8c8ccdc97453b869964e/desugar_jdk_libs-1.0.4.jar:java/util/concurrent/ThreadLocalRandom.class:
  Type `j$.$r8$wrapper$java$util$stream$LongStream$-WRP` was not found, it is required for default or static interface methods desugaring of `$-vivified-$.java.util.stream.LongStream java.util.concurrent.ThreadLocalRandom.longs()`
Warning in /Users/username/.gradle/caches/modules-2/files-2.1/com.android.tools/desugar_jdk_libs/1.0.4/961afbdb3d41eebfb63b8c8ccdc97453b869964e/desugar_jdk_libs-1.0.4.jar:java/util/concurrent/ThreadLocalRandom.class:
  Type `j$.$r8$wrapper$java$util$stream$DoubleStream$-WRP` was not found, it is required for default or static interface methods desugaring of `$-vivified-$.java.util.stream.DoubleStream java.util.concurrent.ThreadLocalRandom.doubles(long)`

Warning: Type `java.util.OptionalConversions` was not found, it is required for default or static interface methods desugaring of `java.util.OptionalLong j$.$r8$wrapper$java$util$stream$LongStream$-WRP.findAny()`
Warning: Type `java.util.LongSummaryStatisticsConversions` was not found, it is required for default or static interface methods desugaring of `java.util.LongSummaryStatistics j$.$r8$wrapper$java$util$stream$LongStream$-WRP.summaryStatistics()`
Warning: Type `java.util.IntSummaryStatisticsConversions` was not found, it is required for default or static interface methods desugaring of `java.util.IntSummaryStatistics j$.$r8$wrapper$java$util$stream$IntStream$-WRP.summaryStatistics()`
Warning: Type `java.util.DoubleSummaryStatisticsConversions` was not found, it is required for default or static interface methods desugaring of `java.util.DoubleSummaryStatistics j$.$r8$wrapper$java$util$stream$DoubleStream$-WRP.summaryStatistics()`

当我运行应用程序并在代码中使用以下 Optional 启动 Activity 时，应用程序崩溃

I/ApplicationBase: Testing Java 8
E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
    Process: com.example.app.DEV, PID: 8265
    java.lang.RuntimeException: An error occured while executing doInBackground()
        at android.os.AsyncTask$3.done(AsyncTask.java:300)
        at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
        at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
        at java.util.concurrent.FutureTask.run(FutureTask.java:242)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
        at java.lang.Thread.run(Thread.java:841)
     Caused by: java.lang.NoClassDefFoundError: j$.util.Optional
        at com.example.app.ApplicationBase.launch(ApplicationBase.java:251)
        at com.example.app.LaunchTask.doInBackground(LaunchTask.java:19)
        at com.example.app.LaunchTask.doInBackground(LaunchTask.java:6)
        at android.os.AsyncTask$2.call(AsyncTask.java:288)

ApplicationBase.java

import androidx.multidex.MultiDexApplication
import java.util.Optional;

public class ApplicationBase extends MultiDexApplication implements LaunchTask.Launcher {
  @SuppressLint("NewApi")
  @Override
  public void launch() throws IOException {
    IOHandler ioHandler = new AndroidAppIOHandler(getApplicationContext());
    Logger.i(TAG, "Testing Java 8");
    Optional.of("xyz").ifPresent(__ -> Logger.i(TAG, "Good"));
    Logger.i(TAG, "Tested Java 8");
    ...
  }
  ...
}

我错过了什么？

看完 @sgjesse's answer ，这似乎确定了 launch() 的问题方法，我们做了一些进一步的调查。我可以确认 MultiDex.install()在 launch() 之前被调用.
如果我添加 Optional在 AndroidAppIoHandler ， 像这样:

public AndroidAppIOHandler(Context context) {
  this.context = context;
  final Optional<Context> context1 = Optional.of(context);
  Log.d("TESTMULTIDEX1", context1.getClass() + "  " + context1.get().getClass() + " " + context1.toString());
}

然后我看到:

D/TESTMULTIDEX1( 2826): class j$.util.Optional  class com.example.app.ApplicationBase Optional[com.example.app.ApplicationBase@9d006a00]

从 launch() 的第一行调用.
如果我添加 Optional到 launch() 的下一行方法，像这样:

public void launch() throws IOException {
  IOHandler ioHandler = new AndroidAppIOHandler(getApplicationContext());
  final Optional<IOHandler> ioHandler1 = Optional.of(ioHandler);
  ...

然后我看到:

java.lang.NoClassDefFoundError: j$.util.Optional

在相同的执行中，在打印上面的其他消息之后!

Answer 1

我在我们的旧版应用程序上遇到了同样的问题，它仍然支持 Android 4.1。在我创建了一个示例项目并尝试重现错误之后，我发现了问题(或错误？)。
不幸的是，4.4 或更低版本的 Android 设备似乎无法使用任何 Java 8 类或接口(interface)，这些类或接口(interface)将在应用程序的 onCreate 方法中被 Core Library Desugaring 触及。
这似乎是一个奇怪的多 dexing 问题/错误。
我尝试了以下方法:

class CoreApplication : MultiDexApplication() {
    override fun attachBaseContext(base: Context?) {
        //adding the new GMS causes to many Methods in APK, therefore configure Application as MultiDex
        super.attachBaseContext(base)
        MultiDex.install(this)
    }

    override fun onCreate() {
        super.onCreate()
        Optional.of("TEst")
    }
}

这将导致您提到的崩溃:

03-22 18:36:09.231 657-657/com.plauzeware.CoreLibraryDesugeringCrashOnAndroidKitkat E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.plauzeware.CoreLibraryDesugeringCrashOnAndroidKitkat, PID: 657
    java.lang.NoClassDefFoundError: j$.util.Optional
        at com.plauzeware.corelibrarydesugeringcrashonandroidkitkat.CoreApplication.onCreate(Application.kt:17)
        at android.app.Instrumentation.callApplicationOnCreate(Instrumentation.java:1030)
        at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4409)
        at android.app.ActivityThread.access$1500(ActivityThread.java:139)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1270)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:136)
        at android.app.ActivityThread.main(ActivityThread.java:5086)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:515)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
        at dalvik.system.NativeStart.main(Native Method)

但是当我在一个助手类中包装对 Optional 的调用时

class Loader {
    companion object {
        fun load() {
            Optional.of("TEst")
        }
    }
}

并在我的 onCreate 函数中调用它

class CoreApplication : MultiDexApplication() {
    override fun attachBaseContext(base: Context?) {
        //adding the new GMS causes to many Methods in APK, therefore configure Application as MultiDex
        super.attachBaseContext(base)
        MultiDex.install(this)
    }

    override fun onCreate() {
        super.onCreate()
        Loader.load()
    }
}

它会起作用的。我认为这是一个错误，我将提交错误报告，并使用指向它的链接更新此答案。
因为多索引问题还涉及基本界面，如 Iterable解决这些错误真的很痛苦。特别是因为我们仍然使用 OrmLite，它将使用 Iterable每时每刻。
我添加了我的代码以供引用我的 Github
更新:
Here是错误报告的链接。