B4X Requires Chilkat v11.0.0+

Get the Root of a JSON Document

See more JSON Examples

Demonstrates how to get back to the JSON root object from anywhere in the JSON document. This example uses the following JSON document:

{
  "flower": "tulip",
  "abc":
    {
    "x": [
       { "a" : 1 },
       { "b1" : 100, "b2" : 200 },
       { "c" : 3 }
    ],
    "y": 200,
    "z": 200
    }
}

B4X

Dim success As Boolean = False

Dim json As ChilkatJsonObject
json.Initialize

Dim jsonStr As String = "{" & Chr(34) & "flower" & Chr(34) & ": " & Chr(34) & "tulip" & Chr(34) & "," & Chr(34) & "abc" & Chr(34) & ":{" & Chr(34) & "x" & Chr(34) & ": [{ " & Chr(34) & "a" & Chr(34) & " : 1 },{ " & Chr(34) & "b1" & Chr(34) & " : 100, " & Chr(34) & "b2" & Chr(34) & " : 200 },{ " & Chr(34) & "c" & Chr(34) & " : 3 }]," & Chr(34) & "y" & Chr(34) & ": 200," & Chr(34) & "z" & Chr(34) & ": 200}}"

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


'  Get the "abc" object.
Dim abcObj As ChilkatJsonObject
abcObj.Initialize
success = json.ObjectOf2("abc", abcObj)
If success = False Then
    Log(json.LastErrorText)
    Return
End If


'  Side note: The JSON of a sub-part of the document can be emitted from any JSON object:
abcObj.EmitCompact = False
Log(abcObj.Emit)

'  Navigate to the "x" array
Dim xArray As ChilkatJsonArray
xArray.Initialize
abcObj.ArrayOf2("x", xArray)

'  Navigate to the 2nd object contained within the array.  This contains members b1 and b2
Dim bObj As ChilkatJsonObject
bObj.Initialize
xArray.ObjectAt2(1, bObj)

'  Show that we're at "b1/b2".
'  The value of "b1" should be "200"
Log("b2 = " & bObj.IntOf("b2"))

'  Now go back to the JSON doc root:
Dim docRoot As ChilkatJsonObject
docRoot.Initialize
bObj.GetDocRoot2(docRoot)

'  We'll skip the null check and assume it's non-null...

'  Pretty-print the JSON doc from the root to show that this is indeed the root.
docRoot.EmitCompact = False
Log(docRoot.Emit)