AndroidConverters number type not recognized

Question

I am trying to implement DateConverterfor persisting date. This is pretty general, but I kept getting:

It is not possible to figure out how to save this field in the database. You might consider adding a type converter to it.

I double-checked and had the annotation defined at the database level as well as at the field level, it is still not able to decide that there is a certain type of type converter.

My file dependencies:

compile('android.arch.persistence.room:runtime:1.0.0-alpha3') {
    exclude group: 'com.google.code.gson'
}
compile('android.arch.persistence.room:rxjava2:1.0.0-alpha3') {
    exclude group: 'com.google.code.gson'
}
testCompile('android.arch.persistence.room:testing:1.0.0-alpha3') {
    exclude group: 'com.google.code.gson'
}
annotationProcessor('android.arch.persistence.room:compiler:1.0.0-alpha3') {
    exclude group: 'com.google.code.gson'
}

In my AppDatabase:

@Database(entities = {Location.class, Room.class, Amenity.class, UserModel.class, EventModel.class}, version =1, exportSchema = false)
@TypeConverters({DateConverter.class})
public abstract class AppDatabase extends RoomDatabase {

    public abstract RoomDao getRoomDao();
    public abstract LocationDao getLocationDao();
    public abstract AmenityDao getAmenityDao();
    public abstract UserDao getUserDao();
    public abstract EventDao getEventDao();

}

Then my class DateConverterlooks like this:

public class DateConverter {

    @TypeConverter
    public static Date toDate(Long timestamp) {
        return timestamp == null ? null : new Date(timestamp);
    }

    @TypeConverter
    public static long toTimestamp(Date date) {
        return date == null ? null : date.getTime();
    }
}

My essence is as follows:

@Entity(tableName = "event")
@TypeConverters({DateConverter.class})
public class EventModel {

    @PrimaryKey
    private String uuid;

    @ColumnInfo(name = "subject")
    private String subject;

    @TypeConverters({DateConverter.class})
    private Date start;

    @TypeConverters({DateConverter.class})
    private Date end;

    @ColumnInfo(name = "confirmed")
    private Boolean confirmed;

    public String getUuid() {return uuid;}
    public void setUuid(String uuid) {this.uuid = uuid;}

    public String getSubject() {return subject;}
    public void setSubject(String subject) {
        this.subject = subject;
    }

    public Date getStart() {return start;}
    public void setStart(Date date) {this.start = date;}

    public Date getEnd() {return end;}
    public void setEnd (Date end) {
        this.end = end;

    }

    public Boolean getConfirmed() {return confirmed;}

    public void setConfirmed(Boolean confirmed) {
        this.confirmed = confirmed;
    }

}

Did I miss something? Thank!

Answer 1

:

public static long toTimestamp(Date date)

public static long toTimestamp(Date date)

long. IOW, .

, , , :

/***
 Copyright (c) 2017 CommonsWare, LLC
 Licensed under the Apache License, Version 2.0 (the "License"); you may not
 use this file except in compliance with the License. You may obtain    a copy
 of the License at http://www.apache.org/licenses/LICENSE-2.0. Unless required
 by applicable law or agreed to in writing, software distributed under the
 License is distributed on an "AS IS" BASIS,    WITHOUT WARRANTIES OR CONDITIONS
 OF ANY KIND, either express or implied. See the License for the specific
 language governing permissions and limitations under the License.

 Covered in detail in the book _Android Architecture Components_
 https://commonsware.com/AndroidArch
 */

package com.commonsware.android.room;

import android.arch.persistence.room.TypeConverter;
import java.util.Date;

public class TypeTransmogrifier {
  @TypeConverter
  public static Long fromDate(Date date) {
    if (date==null) {
      return(null);
    }

    return(date.getTime());
  }

  @TypeConverter
  public static Date toDate(Long millisSinceEpoch) {
    if (millisSinceEpoch==null) {
      return(null);
    }

    return(new Date(millisSinceEpoch));
  }
}

Answer 2

: ( , Im)

class DateConverter {
    @TypeConverter
    fun toDate(timestamp: Long?): Date? {
        return when (timestamp) {
            null -> null
            else -> Date(timestamp)
        }
    }

    @TypeConverter
    fun toTimestamp(date: Date?): Long? {
        return date?.time
    }
}

:

@Database(entities = arrayOf(MyObject::class), version = 1)
@TypeConverters(DateConverter::class)
abstract class MyObjectDb : RoomDatabase() {
    abstract fun myObjectDao(): MyObjectDao
}