I wanna try to make a table to hold 2 columns with Room Library in android studio with Java (not in Kotlin) .

The problem here, is that my data is something like this :

So for this i have made a Class named Data and i valued it like this :

    @Entity(tableName = "tbl_data")
public class Data {
    @PrimaryKey(autoGenerate = true)
    private long id;
    private int year;
    private int dowry;
 
    public Data(int year, int dowry) {
        this.year = year;
        this.dowry = dowry;
    }


    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public int getYear() {
        return year;
    }

    public void setYear(int year) {
        this.year = year;
    }

    public int getDowry() {
        return dowry;
    }

    public void setDowry(int dowry) {
        this.dowry = dowry;
    }
}

and then i made a Database like this :

@Database(version = 1 , exportSchema = false , entities = {Data.class} )
public abstract class AppDatabase extends RoomDatabase   {
        private static AppDatabase appDatabase;


    public static AppDatabase getAppDatabase(Context context) {
            appDatabase= Room.databaseBuilder(context.getApplicationContext(), AppDatabase.class,
                    "db_app")
                    .allowMainThreadQueries()
                    .build();
        return appDatabase;
    }

    public abstract DataDao getDataDao();

}

How to add does data into my data.class AKA "tbl_data" ?

CodePudding user response：

In the DataDao interface (or abstract class) that is annotated with @Dao you could have.

@Insert
long insert(Data data);

You can then insert individual rows e.g.

    db = AppDatabase.getAppDatabase(this);
    dao = db.getDataDao();
    dao.insert(new Data(1317,0004));
    dao.insert(new Data(1318,0004));
    dao.insert(new Data(1319,0004));

The result being (when first run):-

• Database viewed using Android Studio's

  As for handling the string {1317 | 0.004, 1318 | 0.004, 1319 | 0.004, 1320 | 0.008, ... 1400 | 0.255 } for input.

  Then (assuming that ... is and so on) and thus removed then you need to:-

  1. strip off the leading and trailing curly brackets.
  2. split the remaining string into an array at each ,
  3. for each array split at the | removing the spaces and then
  4. create a Data object from the 2 parts
  5. the result should be an Array of Data's that can then be inserted.

  As an example :-

  First yes another dao has been added to mass insert using an ArrayList as per :-

  @Insert
  long[] insert(ArrayList<Data> dataArrayList);
  

  The the following code was added :-

      String datain = "{1317 | 0.004, 1318 | 0.004, 1319 | 0.004, 1320 | 0.008,1400 | 0.255 }";
      ArrayList<Data> newDatas = new ArrayList<>();
      String x = datain.substring(1,datain.length() - 1);
      String[] split1 = x.split(",");
      for (String s: split1) {
          s = s.replace(" | ","~");
          String[] parts = s.split("~");
          if (parts.length == 2) {
              try {
                  newDatas.add(new Data(Integer.parseInt(parts[0].trim()), Double.parseDouble(parts[1].trim())));
              }
              catch (Exception e) {
              }
          }
      }
      dao.insert(newDatas);
  

  With the database now including :-