How to insert an image into a space saving library?

Question

I am using the save space library for my android application. Now I need to insert the image into my db. I have successfully defined @Entity for a primitive data type. and also through the converter class, I saved the whole object, date, time. Now I have to store the image. I cannot understand how we determine the information and the essence of the column and how we insert this data, and also read the data from the table.

What is the maximum size of data inserted on one line? What is the maximum and minimum data size in one field in Android SQLite?

Answer 1

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db BLOB. Room BLOB

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@Entity(tableName = "test")
public class Test{

@PrimaryKey
@ColumnInfo(name = "_id")
private int id;

@ColumnInfo(typeAffinity = ColumnInfo.BLOB)
private byte[] image;
}

Answer 2

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ImageTest.kt

 @Entity    
 class ImageTest {

        @PrimaryKey(autoGenerate = true)

        var id: Int = 1

        @ColumnInfo(typeAffinity = ColumnInfo.BLOB)
        var data: ByteArray? = null
      }

ImageDao.kt

 @Dao
 interface ImageTestDao {

       @Insert(onConflict = OnConflictStrategy.REPLACE)
       fun upsertByReplacement(image: List<ImageTest>)

       @Query("SELECT * FROM image")
       fun getAll(): List<ImageTest>

       @Query("SELECT * FROM image WHERE id IN (:arg0)")
       fun findByIds(imageTestIds: List<Int>): List<ImageTest>

       @Delete
       fun delete(imageTest: ImageTest)
   }

Databse.kt

 import android.arch.persistence.room.Database
 import android.arch.persistence.room.RoomDatabase
 import android.arch.persistence.room.TypeConverters

   @Database(entities = arrayOf(ImageTest::class), version = 1)
   @TypeConverters(DataConverters::class)
   abstract class Database : RoomDatabase() {
    abstract fun getImageTestDao(): ImageTestDao
   }

DatabaseHelper -

  class DatabaseHelper(context: Context) {

   init {
        DatabaseHelper.context = WeakReference(context)
        }

   companion object {

   private var context: WeakReference<Context>? = null
   private const val DATABASE_NAME: String = "image_test_db"
   private var singleton: Database? = null

   private fun createDatabase(): Database {
       return Room.databaseBuilder(context?.get() ?:
               throw IllegalStateException("initialize by calling  
               constructor before calling DatabaseHelper.instance"),
               Database::class.java,
               DATABASE_NAME)
               .build()
   }


   val instance: Database
       @Synchronized get() {
           if (null == singleton)
               singleton = createDatabase()

           return singleton as Database
       }

     fun setImage(img: Bitmap){
     val dao = DatabaseHelper.instance.getImageTestDao() 
     val imageTest = ImageTest()
     imageTest.data = getBytesFromImageMethod(image)//TODO
     dao.updsertByReplacement(imageTest)

     fun getImage():Bitmap?{
     val dao = DatabaseHelper.instance.getImageTestDao() 
     val imageByteArray = dao.getAll()
     return loadImageFromBytes(imageByteArray[0].data)
     //change accordingly 
     }

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