我有一个多模块 Android 项目，使用 Kotlin，数据绑定(bind) v2，在 Android Studio 3.1.3 下。我的大多数支持数据绑定(bind)的布局都包含在库模块中，最终应用程序模块会聚合这些模块。
当我想在我的应用程序模块中添加新布局或从库模块之一覆盖布局时，问题就开始了。使用 <layout> 添加测试布局后标记到应用程序模块，数据绑定(bind)停止生成，并出现以下错误:
error: cannot find symbol
public static TestBinding bind(@NonNull View view, @Nullable DataBindingComponent component) {
^
symbol: class DataBindingComponent
location: class TestBinding
e: error: cannot generate view binders java.lang.NullPointerException
at android.databinding.tool.store.SetterStore.getMatchingMultiAttributeSetters(SetterStore.java:633)
at android.databinding.tool.store.SetterStore.getMultiAttributeSetterCalls(SetterStore.java:520)
at android.databinding.tool.BindingTarget.resolveMultiSetters(BindingTarget.java:220)
at android.databinding.tool.LayoutBinder.<init>(LayoutBinder.java:256)
at android.databinding.tool.DataBinder.<init>(DataBinder.java:55)
at android.databinding.tool.CompilerChef.ensureDataBinder(CompilerChef.java:95)
at android.databinding.tool.CompilerChef.sealModels(CompilerChef.java:259)
at android.databinding.annotationprocessor.ProcessExpressions.writeResourceBundle(ProcessExpressions.java:213)
at android.databinding.annotationprocessor.ProcessExpressions.onHandleStep(ProcessExpressions.java:111)
at android.databinding.annotationprocessor.ProcessDataBinding$ProcessingStep.runStep(ProcessDataBinding.java:203)
at android.databinding.annotationprocessor.ProcessDataBinding$ProcessingStep.access$000(ProcessDataBinding.java:188)
at android.databinding.annotationprocessor.ProcessDataBinding.doProcess(ProcessDataBinding.java:90)
at android.databinding.annotationprocessor.ProcessDataBinding.process(ProcessDataBinding.java:65)
at org.jetbrains.kotlin.kapt3.ProcessorWrapper.process(annotationProcessing.kt:131)
at com.sun.tools.javac.processing.JavacProcessingEnvironment.callProcessor(JavacProcessingEnvironment.java:794)
at com.sun.tools.javac.processing.JavacProcessingEnvironment.discoverAndRunProcs(JavacProcessingEnvironment.java:705)
at com.sun.tools.javac.processing.JavacProcessingEnvironment.access$1800(JavacProcessingEnvironment.java:91)
at com.sun.tools.javac.processing.JavacProcessingEnvironment$Round.run(JavacProcessingEnvironment.java:1035)
at com.sun.tools.javac.processing.JavacProcessingEnvironment.doProcessing(JavacProcessingEnvironment.java:1176)
at com.sun.tools.javac.main.JavaCompiler.processAnnotations(JavaCompiler.java:1170)
at com.sun.tools.javac.main.JavaCompiler.processAnnotations(JavaCompiler.java:1068)
at org.jetbrains.kotlin.kapt3.AnnotationProcessingKt.doAnnotationProcessing(annotationProcessing.kt:87)
at org.jetbrains.kotlin.kapt3.AnnotationProcessingKt.doAnnotationProcessing$default(annotationProcessing.kt:45)
at org.jetbrains.kotlin.kapt3.AbstractKapt3Extension.runAnnotationProcessing(Kapt3Extension.kt:257)
at org.jetbrains.kotlin.kapt3.AbstractKapt3Extension.analysisCompleted(Kapt3Extension.kt:212)
at org.jetbrains.kotlin.kapt3.ClasspathBasedKapt3Extension.analysisCompleted(Kapt3Extension.kt:95)
at org.jetbrains.kotlin.cli.jvm.compiler.TopDownAnalyzerFacadeForJVM$analyzeFilesWithJavaIntegration$2.invoke(TopDownAnalyzerFacadeForJVM.kt:97)
at org.jetbrains.kotlin.cli.jvm.compiler.TopDownAnalyzerFacadeForJVM.analyzeFilesWithJavaIntegration(TopDownAnalyzerFacadeForJVM.kt:107)
at org.jetbrains.kotlin.cli.jvm.compiler.TopDownAnalyzerFacadeForJVM.analyzeFilesWithJavaIntegration$default(TopDownAnalyzerFacadeForJVM.kt:84)
at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler$analyze$1.invoke(KotlinToJVMBytecodeCompiler.kt:374)
at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler$analyze$1.invoke(KotlinToJVMBytecodeCompiler.kt:64)
at org.jetbrains.kotlin.cli.common.messages.AnalyzerWithCompilerReport.analyzeAndReport(AnalyzerWithCompilerReport.kt:101)
at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.analyze(KotlinToJVMBytecodeCompiler.kt:365)
at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.compileModules$cli(KotlinToJVMBytecodeCompiler.kt:130)
at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:161)
at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:63)
at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.java:107)
at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.java:51)
at org.jetbrains.kotlin.cli.common.CLITool.exec(CLITool.kt:96)
at org.jetbrains.kotlin.daemon.CompileServiceImpl$compile$1$1$2.invoke(CompileServiceImpl.kt:405)
at org.jetbrains.kotlin.daemon.CompileServiceImpl$compile$1$1$2.invoke(CompileServiceImpl.kt:98)
at org.jetbrains.kotlin.daemon.CompileServiceImpl$doCompile$$inlined$ifAlive$lambda$2.invoke(CompileServiceImpl.kt:920)
at org.jetbrains.kotlin.daemon.CompileServiceImpl$doCompile$$inlined$ifAlive$lambda$2.invoke(CompileServiceImpl.kt:98)
at org.jetbrains.kotlin.daemon.common.DummyProfiler.withMeasure(PerfUtils.kt:137)
at org.jetbrains.kotlin.daemon.CompileServiceImpl.checkedCompile(CompileServiceImpl.kt:950)
at org.jetbrains.kotlin.daemon.CompileServiceImpl.doCompile(CompileServiceImpl.kt:919)
at org.jetbrains.kotlin.daemon.CompileServiceImpl.compile(CompileServiceImpl.kt:404)
at sun.reflect.GeneratedMethodAccessor101.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:357)
at sun.rmi.transport.Transport$1.run(Transport.java:200)
at sun.rmi.transport.Transport$1.run(Transport.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:196)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:568)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:826)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:683)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:682)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
全部 DataBindingComponent正在生成来自库模块的接口(interface)，只有来自应用程序模块的接口(interface)没有生成。
最佳答案
我在迁移到 androidx 命名空间后遇到了类似的问题。确保您已更新:
1.你的 gradle wrapper 到 4.10.1 in gradle-wrapper-properties
2.你使用gradle构建插件3.3.0-beta-1
使用此配置，一切正常。还要确保您在 app.gradle 中没有任何数据绑定(bind) kapt 或 apt 注释依赖项，因为 3.2.0 已经绑定(bind)到 gradle 了
关于多模块项目的 Android Databinding V2 失败，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/51177913/