Android Question How to use 'Wait for' when loading data in a spinner

demonio_jack · Mar 9, 2020

Hi everyone!!!
I'm loading data from a database and I don't know how to show a progressbar during the process. Just want to show a progress circle to show users that data is loading...

this is teh code:
'********************************************

B4X:

Sub CargarDatosJ
    Try
        pgbBarra.Visible=True
       
        Starter.Connect
        Dim cur As JdbcResultSet= Starter.mysql.ExecQuery("select concat(idcategoria,' - ',nombre) categoria from categorias1 where activa=1 order by nombre")
        Do While cur.NextRow
            spnCategorias.add(cur.GetString("categoria"))
        Loop
        spnCategorias.SelectedIndex=6
        cur.Close
        Dim niv As JdbcResultSet = Starter.mysql.ExecQuery("select concat(idnivel,' - ',descripcion) nivel from niveles")
        Do While niv.NextRow
            spnNiveles.add(niv.GetString("nivel"))
        Loop
        spnNiveles.SelectedIndex=1
        niv.Close
    Catch
        Log(LastException)
    End Try
    Starter.CloseConnection
    pgbBarra.Visible=False
End Sub

'********************************************
Any idea???

Thanks. ;-)

Erel · Mar 9, 2020

Please use [code]code here...[/code] tags when posting code.

Erel · Mar 9, 2020

demonio_jack said:
Any idea???

Yes. You are making synchronous remote queries. This is a big mistake.

I assume that you are using JdbcSQL. Switch to the async methods.
[B4X] SQL with Wait For

Peter Simpson · Mar 9, 2020

Hey @demonio_jack

First you need to know how many records you are going to return
In your Do While make sure to have a counter i + i + 1 etc
Use following code to map the record counter range to the progress bar value, you will need Sleep(0)

✅ MapRange Mapping A-B to C-D

SubName: Map a range of numbers from A-B to C-D and return the mapped value. Description: I use B4R a lot and that package includes a function called MapRange. B4A doesn't have a version of MapRange and I couldn't find one on the forum anywhere, so I found the formula online and I put together...

www.b4x.com

How many records are you returning???

Erel · Mar 9, 2020

The problem is in the query itself. You must use async methods with remote databases.

demonio_jack · Mar 9, 2020

Erel said:
The problem is in the query itself. You must use async methods with remote databases.

Thanks Erel!!! I'll try the new solution with async methods. ;-)

demonio_jack · Mar 9, 2020

Peter Simpson said:
Hey @demonio_jack

First you need to know how many records you are going to return

In your Do While make sure to have a counter i + i + 1 etc

Use following code to map the record counter range to the progress bar value, you will need Sleep(0)

✅ MapRange Mapping A-B to C-D

SubName: Map a range of numbers from A-B to C-D and return the mapped value. Description: I use B4R a lot and that package includes a function called MapRange. B4A doesn't have a version of MapRange and I couldn't find one on the forum anywhere, so I found the formula online and I put together...

www.b4x.com

How many records are you returning???

not over 100 rows..

Android Question How to use 'Wait for' when loading data in a spinner

demonio_jack

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Erel

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Erel

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Peter Simpson

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✅ MapRange Mapping A-B to C-D

Erel

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demonio_jack

Member

demonio_jack

Member

✅ MapRange Mapping A-B to C-D

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