我尝试在Android Studio中使用现有的SQLite数据库。它可以在Android 10+中工作，但在Android 9及以下版本中，我会收到此错误：
无此表
DatabaseHelper类：

package com.example.testlocaldatabase;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Build;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class DatabaseHelper extends SQLiteOpenHelper {

  private static String DB_NAME = "myDatabase.SqLite";
  private static String DB_PATH = "";
  private static int DB_VERSION = 1;

  private SQLiteDatabase database;
  private Context context;
  private boolean needUpdate = false;

  public DatabaseHelper(Context context) {
    super(context, DB_NAME, null, DB_VERSION);
    if (Build.VERSION.SDK_INT >= 17) {
      DB_PATH = context.getApplicationInfo().dataDir + "/databases/";

    } else {
      DB_PATH = "/data/data/" + context.getPackageName() + "/databases/";
    }
    this.context = context;
    copyDatabase();
    this.getReadableDatabase();
  }

  @Override
  public void onCreate(SQLiteDatabase sqLiteDatabase) {

  }

  @Override
  public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
    if (i1 > i) {
      needUpdate = true;
    }

  }

  private void copyDatabase() {

    if (!checkDatabase()) {
      this.getReadableDatabase();
      this.close();
      try {
        copyDBFile();
      } catch (IOException e) {
        throw new Error("Error copying database");
      }//catch
    }//if
  }//copyDatabase

  private boolean checkDatabase() {
    File dbFile = new File(DB_PATH + DB_NAME);
    if (dbFile.exists()) {
      return true;
    } else {
      return false;
    }
  }

  private void copyDBFile() throws IOException {
    InputStream inputStream = context.getAssets().open(DB_NAME);
    OutputStream outputStream = new FileOutputStream(DB_PATH + DB_NAME);
    byte[] buffer = new byte[1024];
    int length;
    while ((length = inputStream.read(buffer)) > 0) {
      outputStream.write(buffer, 0, length);
    }
    outputStream.flush();
    outputStream.close();
    inputStream.close();
  }

  public void updateDatabase() throws IOException {
    if (needUpdate) {
      File dbFile = new File(DB_PATH + DB_NAME);
      if (dbFile.exists())
        dbFile.delete();
      copyDatabase();
      needUpdate = false;

    }//if
  }//updateDatabase

  @Override
  public synchronized void close() {
    if (database != null) {
      database.close();
    }
    super.close();

  }
}

字符串
MainActivity：

package com.example.testlocaldatabase;

import androidx.appcompat.app.AppCompatActivity;

import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.util.Log;
import java.io.IOException;

public class MainActivity extends AppCompatActivity {

  private DatabaseHelper databaseHelper;
  private SQLiteDatabase database;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    databaseHelper = new DatabaseHelper(MainActivity.this);
    try {
      databaseHelper.updateDatabase();
    } catch (IOException e) {
      e.printStackTrace();
    }
    database = databaseHelper.getReadableDatabase();

    // pull out data from database
    Cursor cursor = database.rawQuery("select * from drugs", null);
    while (cursor.moveToNext()) {
      String b = cursor.getString(cursor.getColumnIndexOrThrow("drugName"));
      Log.i("LOG", "" + b);
    }
    cursor.close();

  }

}

型
logcat中的错误行：
android.database.sqlite.SQLiteException:无此表：药物（代码1 SQLITE_ERROR）：，编译时：从药物中选择 *