房间找不到实施
我在测试一个Room数据库时遇到了问题：当我运行测试时，出现以下exception：
java.lang.RuntimeException: cannot find implementation for database.TicketDatabase. TicketDatabase_Impl does not exist at android.arch.persistence.room.Room.getGeneratedImplementation(Room.java:92) at android.arch.persistence.room.RoomDatabase$Builder.build(RoomDatabase.java:454) at com.sw.ing.gestionescontrini.DatabaseTest.setDatabase(DatabaseTest.java:36) at java.lang.reflect.Method.invoke(Native Method) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:24) at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.junit.runners.Suite.runChild(Suite.java:128) at org.junit.runners.Suite.runChild(Suite.java:27) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.junit.runner.JUnitCore.run(JUnitCore.java:137) at org.junit.runner.JUnitCore.run(JUnitCore.java:115) at android.support.test.internal.runner.TestExecutor.execute(TestExecutor.java:59) at android.support.test.runner.AndroidJUnitRunner.onStart(AndroidJUnitRunner.java:262) at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:1886) Class DatabaseTest：
public class DatabaseTest { TicketDatabase database; DAO ticketDAO; @Before public void setDatabase() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException { Context context = InstrumentationRegistry.getTargetContext(); database = Room.inMemoryDatabaseBuilder(context, TicketDatabase.class).build(); Method method = TicketDatabase.class.getDeclaredMethod("ticketDao()"); method.setAccessible(true); ticketDAO = (DAO) method.invoke(database, null); } }
gradle文件：
apply plugin: 'com.android.application' android { compileSdkVersion 26 buildToolsVersion '26.0.2' defaultConfig { applicationId "com.sw.ing.gestionescontrini" minSdkVersion 15 targetSdkVersion 26 versionCode 1 versionName "1.0" testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner" } defaultConfig { multiDexEnabled true } buildTypes { release { minifyEnabled false proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' } } } dependencies { compile fileTree(dir: 'libs', include: ['*.jar']) androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', { exclude group: 'com.android.support', module: 'support-annotations' }) compile 'com.android.support:appcompat-v7:26.+' compile 'com.android.support.constraint:constraint-layout:1.0.2' testCompile 'junit:junit:4.12' annotationProcessor 'android.arch.lifecycle:compiler:1.0.0' compile 'android.arch.persistence.room:rxjava2:1.0.0-rc1' testCompile'android.arch.persistence.room:testing:1.0.0-rc1' }
我真的不知道这个实现应该是什么，我搜索了一个解决方案，但我发现并不适合我。 例如，许多人发现一个解决方案，加入kapt“android.arch.persistence.room …”，但gradle不认识“kapt”。
kapt是Kotlin。
首先，添加：
annotationProcessor "android.arch.persistence.room:compiler:1.0.0"
关闭你的dependencies 。
然后，将android.arch.persistence.room:rxjava2和android.arch.persistence.room:testing升级到1.0.0而不是1.0.0-rc1 。