要将Android Room数据库保存并导出为SQLite格式,可以按照以下步骤进行操作:
implementation 'androidx.room:room-runtime:2.2.6'
kapt 'androidx.room:room-compiler:2.2.6'
@Database(entities = {User.class}, version = 1, exportSchema = false)
public abstract class MyDatabase extends RoomDatabase {
public abstract UserDao userDao();
}
@Entity(tableName = "users")
public class User {
@PrimaryKey
public int id;
public String name;
public int age;
}
@Dao
public interface UserDao {
@Query("SELECT * FROM users")
List getAllUsers();
@Insert
void insertUser(User user);
// 其他操作方法...
}
MyDatabase database = Room.databaseBuilder(getApplicationContext(), MyDatabase.class, "my-db")
.allowMainThreadQueries()
.build();
List users = database.userDao().getAllUsers();
// 导出为SQLite文件
File dbFile = getDatabasePath("my-db");
File exportDir = new File(Environment.getExternalStorageDirectory(), "exports");
exportDir.mkdirs();
File exportFile = new File(exportDir, "my-db.sqlite");
try {
FileUtils.copyFile(dbFile, exportFile);
Toast.makeText(getApplicationContext(), "导出成功", Toast.LENGTH_SHORT).show();
} catch (IOException e) {
e.printStackTrace();
Toast.makeText(getApplicationContext(), "导出失败", Toast.LENGTH_SHORT).show();
}
在上述示例中,我们首先获取数据库文件的路径,然后创建一个导出目录,并将数据库文件复制到该目录中。
请注意,为了避免在主线程中执行数据库操作而引发的异常,我们在创建数据库实例时调用了allowMainThreadQueries()
方法。在实际项目中,应该避免在主线程中执行数据库操作,而是使用异步任务或其他线程来执行。