当我将 Room 持久性库添加到我的库中时，无法从 .aar 文件加载 class

Question

我目前正在开发一个报警库，需要在sqlite数据库中存储多个报警细节。所以我使用了 google 的 Room 持久性库和我的警报库。

我已将以下代码添加到 build.gradle。

implementation 'android.arch.persistence.room:runtime:1.1.1'
annotationProcessor 'android.arch.persistence.room:compiler:1.1.1'

我添加了数据库class

@Database(entities = AlarmDetails.class, version = 1)
public abstract class AlarmDatabase extends RoomDatabase {

  public abstract AlarmDao alarmDao();
}

我还添加了数据访问对象

@Dao
public interface AlarmDao {

  @Insert(onConflict = OnConflictStrategy.REPLACE)
  void insert(AlarmDetails alarmDetails);

  @Update
  void update(AlarmDetails alarmDetails);

  @Delete
  void delete(AlarmDetails alarmDetails);

  @Query("SELECT * FROM alarms")
  List<AlarmDetails> getAll();
}

我正在我的库的主 class 中创建一个数据库实例，如下所示

/*Constructor*/
public AlarmBase(Context mcontext,Context ncontext) {
    this.mContext = mcontext;

    alarmDatabase= Room.databaseBuilder(ncontext,
            AlarmDatabase.class, "alarm_db")
            .build();
}

我正在从我的演示项目中调用上述构造函数并按如下方式传递应用程序上下文

Context applicationContext=MyApplicationClass.getContext();
    alarmBase = new AlarmBase(this,applicationContext);

这是我的申请class

public class MyApplicationClass extends MultiDexApplication {
  private static MultiDexApplication instance;

  @Override
  public void onCreate() {
    super.onCreate();
    instance = this;
  }

  public static Context getContext() {
    return instance.getApplicationContext();
  }
}

但是当我运行项目时，我得到以下错误

    --------- beginning of crash
02-21 20:23:34.643 11930-11930/com.mid.alarmdemo E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.mid.alarmdemo, PID: 11930
java.lang.NoClassDefFoundError: Failed resolution of: Lcom/mid/alarmlib/roomsqlite/AlarmDatabase;
    at com.mid.alarmlib.AlarmBase.<init>(AlarmBase.java:39)
    at com.mid.alarmdemo.MainActivity.onCreate(MainActivity.java:54)
    at android.app.Activity.performCreate(Activity.java:6362)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1108)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2441)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2548)
    at android.app.ActivityThread.access00(ActivityThread.java:154)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1399)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:157)
    at android.app.ActivityThread.main(ActivityThread.java:5613)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:774)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:652)
 Caused by: java.lang.ClassNotFoundException: Didn't find class "com.mid.alarmlib.roomsqlite.AlarmDatabase" on path: DexPathList[[zip file "/data/app/com.mid.alarmdemo-1/base.apk"],nativeLibraryDirectories=[/data/app/com.mid.alarmdemo-1/lib/arm64, /vendor/lib64, /system/lib64]]
    at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
    at com.mid.alarmlib.AlarmBase.<init>(AlarmBase.java:39) 
    at com.mid.alarmdemo.MainActivity.onCreate(MainActivity.java:54) 
    at android.app.Activity.performCreate(Activity.java:6362) 
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1108) 
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2441) 
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2548) 
    at android.app.ActivityThread.access00(ActivityThread.java:154) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1399) 
    at android.os.Handler.dispatchMessage(Handler.java:102) 
    at android.os.Looper.loop(Looper.java:157) 
    at android.app.ActivityThread.main(ActivityThread.java:5613) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:774) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:652) 
    Suppressed: java.lang.NoClassDefFoundError: com.mid.alarmlib.roomsqlite.AlarmDatabase
    at dalvik.system.DexFile.defineClassNative(Native Method)
    at dalvik.system.DexFile.defineClass(DexFile.java:226)
    at dalvik.system.DexFile.loadClassBinaryName(DexFile.java:219)
    at dalvik.system.DexPathList.findClass(DexPathList.java:338)
    at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:54)
            ... 16 more
    Suppressed: java.lang.ClassNotFoundException: com.mid.alarmlib.roomsqlite.AlarmDatabase
    at java.lang.Class.classForName(Native Method)
    at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
    at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
            ... 15 more
 Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack trace available

在我将 Room 持久性添加到我的库之前，我能够运行项目和我的库

Answer 1

我刚刚在项目的 build.gradle（模块应用程序）中添加了以下行，

implementation 'android.arch.persistence.room:runtime:1.1.1'
annotationProcessor 'android.arch.persistence.room:compiler:1.1.1'

而且效果很好

当我将 Room 持久性库添加到我的库中时，无法从 .aar 文件加载 class

Cannot load class from .aar file when i added Room persistence library into my library

sqlite

android

android-library

android-sqlite

android-multidex