B4X

Get the Index of a JSON Member

See more JSON Examples

This example demonstrates how to get the index of a given member by name.

{
  "name": "donut",
  "image":
    {
    "fname": "donut.jpg",
    "w": 200,
    "h": 200
    },
  "thumbnail":
    {
    "fname": "donutThumb.jpg",
    "w": 32,
    "h": 32
    }
}

B4X

Dim success As Boolean = False

Dim json As ChilkatJsonObject
json.Initialize

'  This is the above JSON with whitespace chars removed (SPACE, TAB, CR, and LF chars).
'  The presence of whitespace chars for pretty-printing makes no difference to the Load
'  method. 
Dim jsonStr As String = "{" & Chr(34) & "name" & Chr(34) & ": " & Chr(34) & "donut" & Chr(34) & "," & Chr(34) & "image" & Chr(34) & ":{" & Chr(34) & "fname" & Chr(34) & ": " & Chr(34) & "donut.jpg" & Chr(34) & "," & Chr(34) & "w" & Chr(34) & ": 200," & Chr(34) & "h" & Chr(34) & ": 200}," & Chr(34) & "thumbnail" & Chr(34) & ":{" & Chr(34) & "fname" & Chr(34) & ": " & Chr(34) & "donutThumb.jpg" & Chr(34) & "," & Chr(34) & "w" & Chr(34) & ": 32," & Chr(34) & "h" & Chr(34) & ": 32}}"

success = json.Load(jsonStr)
If success = False Then
    Log(json.LastErrorText)
    Return
End If


'  The top-level JSON object has three members: name, image, and thumbnail.
Dim nameIndex As Int = json.IndexOf("name")
'  The index of the "name" member is 0.
Log("nameIndex = " & nameIndex)

Dim thumbIndex As Int = json.IndexOf("thumbnail")
'  The index of the "thumbnail" member is 2.
Log("thumbIndex = " & thumbIndex)

'  The "fname" member is NOT a direct member of the top-level JSON object.
'  It is a member of a nested object.  If we try to get the index of this
'  member using the top-level JSON object, it is not found (and returns -1).
Dim fnameIndex As Int = json.IndexOf("fname")
'  The fnameIndex is -1 (not found).  This is correct.
Log("fnameIndex = " & fnameIndex)

'  Get the "image" object.
Dim imageObj As ChilkatJsonObject
imageObj.Initialize
json.ObjectOf2("image", imageObj)

'  Now we can get the index of the "fname" object, because it is a direct
'  member of the "image" object:
fnameIndex = imageObj.IndexOf("fname")
Log("fnameIndex = " & fnameIndex)