Android Question XML -> MAP issue

yo3ggx · Dec 17, 2023

This is just a simplified example to explain the issue I have.
I'm using XML2MAP to covert a simple xml file:

B4X:

<root>
    <config>
        <param1>val11</param1>
        <param2>val12</param2>
        <param3>val13</param3>
    </config>
    <config>
        <param1>val21</param1>
        <param2>val22</param2>
        <param3>val23</param3>
    </config>
</root>

And the following code:

B4X:

Dim Parsed As Map = xm.Parse(xmlfile)
Dim mp as Map = Parsed.Get("list")
Dim lst As List
lst = GetElements(mp,"config")
Log("lst size = " & lst.Size)
File.WriteMap(File.DirInternal,"example.map",mp)
mp = File.ReadMap(sLocalRepository,"example.map")
lst = GetElements(mp,"config")
Log("lst size = " & lst.Size)

And the routine GetElements

B4X:

Sub GetElements (m As Map, key As String) As List
    Dim res As List
    If m.ContainsKey(key) = False Then
        res.Initialize
        Return res
    Else
        Dim value As Object
         value = m.Get(key)
        Log(key & ": " & value)
        If value Is List Then Return value
        res.Initialize
        res.Add(value)
        Return res
    End If
End Sub

The problem is that if I save the map and theN I read it from the file, GetElements(mp,"config") does no more return a list, but a single element as a string.
Logging the two 'value' objects, looks absolutely the same.

I am doing something wrong?

Thank you

William Lancee · Dec 17, 2023

File.WriteMap converts all values to a string and saves one key: string-Value as a pair on each record/line in the file.
The List is converted to a string. When read it is still a string. When you log the list and string they look the same.

You need to use the B4XSerializator from the internal RandomAccessFile library.

B4X:

    Dim BS As B4XSerializator
    File.WriteBytes(File.DirApp,"example.txt", BS.ConvertObjectToBytes(mp1))
    Dim mp3 As Map = BS.ConvertBytesToObject(File.ReadBytes(File.DirApp,"example.txt"))
    Dim lst3 As List = GetElements(mp3,"config")
    Log(lst3.Size & TAB & lst3.Get(0))

aeric · Dec 18, 2023

I think this is a duplicate post and already answered here

XML2MAP and lists of maps

Hello, Let's consider the following simple xml file as xmlstring. 123456 654321 45678 87654 I'm using the following code to extract memories parameters in a list. Dim xm as XML2MAP xm.Initialize...

www.b4x.com

yo3ggx · Dec 18, 2023

aeric said:
I think this is a duplicate post and already answered here

XML2MAP and lists of maps

Hello, Let's consider the following simple xml file as xmlstring. 123456 654321 45678 87654 I'm using the following code to extract memories parameters in a list. Dim xm as XML2MAP xm.Initialize...

www.b4x.com

Is not duplicate. List in a map is working according to Erel solution, but if you save the map and load the map again from the file, the list of maps is lost. I will try William suggestion.

aeric · Dec 18, 2023

yo3ggx said:
Is not duplicate. List in a map is working according to Erel solution, but if you save the map and load the map again from the file, the list of maps is lost. I will try William suggestion.

I see. Maybe I was confused with the title. It should have mentioned about saving and reading from file.

yo3ggx · Dec 18, 2023

William Lancee said:
File.WriteMap converts all values to a string and saves one key: string-Value as a pair on each record/line in the file.
The List is converted to a string. When read it is still a string. When you log the list and string they look the same.

You need to use the B4XSerializator from the internal RandomAccessFile library.

B4X:

Dim BS As B4XSerializator File.WriteBytes(File.DirApp,"example.txt", BS.ConvertObjectToBytes(mp1)) Dim mp3 As Map = BS.ConvertBytesToObject(File.ReadBytes(File.DirApp,"example.txt")) Dim lst3 As List = GetElements(mp3,"config") Log(lst3.Size & TAB & lst3.Get(0))

This was the solution for my problem. Thank you.

I was not aware that WriteMap does not save the map in the right format. Then there is any difference between WriteMap and WriteString?

aeric · Dec 18, 2023

I prefer to work with JSON library. The format is human readable.

B4X:

Dim xmlfile As String = File.ReadString(File.DirApp, "example.xml")

Dim xm As Xml2Map
xm.Initialize
Dim Parsed As Map = xm.Parse(xmlfile)
'Log(Parsed.As(JSON).ToString)

Dim root As Map = Parsed.Get("root")
Dim config As List
config = GetElements(root, "config")
Log("lst size = " & config.Size)

File.WriteString(File.DirApp, "example.map", root.As(JSON).ToString)
Dim mapfile As String = File.ReadString(File.DirApp, "example.map")
'Log(mapfile)
config = GetElements(mapfile.As(JSON).ToMap, "config")
Log("lst size = " & config.Size)

Code only tested in B4J. You may change File.DirApp to File.Internal in B4A.

William Lancee · Dec 18, 2023

To find out quickly what a method does, simply hover over its name and read the Intellisense.

yo3ggx · Dec 25, 2023

William Lancee said:
To find out quickly what a method does, simply hover over its name and read the Intellisense.

I was aware that WriteMap create a text file, with list represented using '{}', but I expected that ReadMap do the reverse and reconstruct the list from the string.

aeric · Dec 25, 2023

yo3ggx said:
I was aware that WriteMap create a text file, with list represented using '{}', but I expected that ReadMap do the reverse and reconstruct the list from the string.

List should be represented by [ ].

yo3ggx · Dec 25, 2023

aeric said:
List should be represented by [ ].

I mean map of lists.

Android Question XML -> MAP issue

yo3ggx

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William Lancee

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aeric

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XML2MAP and lists of maps

yo3ggx

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XML2MAP and lists of maps

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Android Question XML -> MAP issue

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