Android Question convert byte to string

[FormCommander]

Hello,
I store a XML with base64 encoded images into a SQL blob field and want to read it back into a string for parsing. But I get an error
Cannot cast type {Type=Byte,Rank=0,ReomoteObject=True}to:{Type=Byte,Rank=1,RemoteObject=True}

Dim bc As ByteConverter
             Dim cBytes As Byte
            cBytes = Cursor1.GetBlob("XML")
             Dim cXML As String = bc.StringFromBytes(cBytes)

So what I am doing wrong with the conversation ?
And I am right that it is possibe to parse the base64 encoded image fields from the XML back with Xml2Map or Sax ?

 

[udg]

You defined cbytes as a single byte

 

[Erel]

Dim cBytes() As Byte = Cursor1.GetBlob("XML")
Dim cXML As String = BytesToString(cBytes, 0, cBytes.Length, "UTF8")

 

[FormCommander]

Hello,
thank you for your answers, I do it the way Erel posted. But now I get an sql error. The XML I store in the blob field is correct, I can open it in any other viewer like XM notepad. Also the other fields are no problem. What can be wrong ?
regards
Rudolf

Dim Cursor1 As Cursor
Cursor1 = Main.SQLobj.ExecQuery("SELECT ID,XML,BARCODE,OBJECT FROM document WHERE BARCODE = '" & Main.cBarCode & "'" )
For i = 0 To Cursor1.RowCount - 1
      Cursor1.Position = i
      Dim bytes() As Byte = Cursor1.GetBlob("XML") 'Line 41



Error occurred on line: 41 (doclist)
java.lang.IllegalStateException: Couldn't read row 0, col 1 from CursorWindow.  Make sure the Cursor is initialized correctly before accessing data from it.
    at android.database.CursorWindow.nativeGetBlob(Native Method)
    at android.database.CursorWindow.getBlob(CursorWindow.java:416)
    at android.database.AbstractWindowedCursor.getBlob(AbstractWindowedCursor.java:45)
    at anywheresoftware.b4a.sql.SQL$CursorWrapper.GetBlob(SQL.java:422)
    at java.lang.reflect.Method.invoke(Native Method)
    at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:710)
    at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:339)
    at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:249)
    at java.lang.reflect.Method.invoke(Native Method)
    at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:139)
    at anywheresoftware.b4a.samples.camera.doclist.afterFirstLayout(doclist.java:102)
    at anywheresoftware.b4a.samples.camera.doclist.access$000(doclist.java:17)
    at anywheresoftware.b4a.samples.camera.doclist$WaitForLayout.run(doclist.java:80)
    at android.os.Handler.handleCallback(Handler.java:751)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:154)
    at android.app.ActivityThread.main(ActivityThread.java:6776)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1496)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1386)

 

[Erel]

Cursor1 = Main.SQLobj.ExecQuery("SELECT ID,XML,BARCODE,OBJECT FROM document WHERE BARCODE = '" & Main.cBarCode & "'" )

You shouldn't write such queries. Please watch this tutorial:


Is it possible that the blob data is larger than 1mb?

 

[FormCommander]

Hello Erel,
thank you, have checked the database with ODBC on my Windows computer, no problem to open a cursor and retrieve the XML. I have changed my code as recommended in you excellent video, I think this is all correct now. But get still an error. I will try tp make a little B4J program to try to get the XML fields. The size of the blob is smaller than 1 mb, is not more possible or problems expectec ?
regards
Rudolf

 

[Erel]

There is a limit of 1mb or 2mb depending on the Android device.

If you like you can upload the database file and we will try it.

 

[FormCommander]

Hello,
the same with B4J on Windows works without problems. So it is related only to B4A
regards
Rudolf

 

[FormCommander]

Hello Erel,
thank you, I wil make a little test program in B4A
regards
Rudolf

 

[FormCommander]

Hello, found that one image was a little bit more than 1 MB, it seens that I can store the image, but then it is not possible to open an cursor on this table. I will store the images in files instead of the sql table.
Thank you all for your help
regards
Rudolf

 

[DonManfred]

images in files instead of the sql table

It is a bad practice to store images in the Database. In SQlite it is mandatory not to store big images as you just found out.
Store it on Disc and only store the filename in the Database.

 

[FormCommander]

Hello Manfred,
I am a beginner, I have learned now something ;-) I do it exact this way now.
regards
Rudolf