Help on reading values from a JSON array

[Magno 4]

Hi! Well I am struggling on this, maybe it's late and I am tired enough, I'd appreciate any help with. Below my function:
 

type
  TReadings = record
    Time: Integer;
    Flex: Boolean;
    Message: String;
end;  

function GetReadings: TReadings;
var
   JSonObject: TJSONObject;
   JSonValue: TJSonValue;
   JsonArray: TJSONArray;
   ArrayElement: TJSonValue;
   s: string;
begin
   Result.Message := '';
   Result.Time := 0;
   Result.Flex := false;
   // example of a json
   s := '{"A":0,"B":0,"C":1,"D":0,"K":{"T":"X","acc":81,"max":116},"result":[{"type":{"TP":30.3,"message":'+
        '"Added successfuly"},"time":503,"flex":"yes"}]}';

   JSonValue := TJSonObject.ParseJSONValue(s);
   JsonArray := JSonValue.GetValue<TJSONArray>('result');

   for ArrayElement in JsonArray do
    // how do I could read message, time and flex values?

   JSonValue.Free;
end;

I need to read that 3 values inside the array. So far I can move the array into the JsonArray but I don't know how to extract the values. Of course I could made a string parse and solve the issue, but I am will be glad if I can fix it using that Json classes to populate the result record.

 

Again, thanks for any help.

[programmerdelphi2k 235]

You has many levels in this JSON...

some like this...

 

uses
  System.JSON;

procedure TForm1.Button1Click(Sender: TObject);
var
  s : string;
  jv: TJSONValue;
  ja: TJSONArray;
  jo: TJSONObject;
  jp: TJSONPair;
begin
  s := '{"A":0,"B":0,"C":1,"D":0,' +      { }
    '"K":{"T":"X","acc":81,"max":116},' + { }
    '"result":[{"type":{"TP":30.3,"message":"Added successfuly"},"time":503,"flex":"yes"}]}';
  //
  try
    jo := TJSONValue.ParseJSONValue(s) as TJSONObject; // if JSON is good, go ahead. Else, break with an Exception!
    //
    try
      jp         := jo.Get('result'); // 'K', 'result' // direct to the point!
      Memo1.Text := jp.JsonValue.ToString;
      //
      if jp.JsonValue is TJSONObject then
        for var i: integer := 0 to TJSONObject(jp.JsonValue).Count - 1 do
          begin
            // Memo1.Lines.Add(TJSONObject(jp.JsonValue).Pairs[i].ToJSON)
            Memo1.Lines.Add(TJSONObject(jp.JsonValue).Pairs[i].JsonString.ToString + ' is ' + TJSONObject(jp.JsonValue).Pairs[i].JsonValue.ToString);
          end
      else // array
        begin
          for var A in TJSONArray(jp.JsonValue) do
            if A is TJSONObject then
              for var z: integer := 0 to (TJSONObject(A).Count - 1) do
                Memo1.Lines.Add(TJSONObject(A).Pairs[z].JsonString.ToString + ' is ' + TJSONObject(A).Pairs[z].JsonValue.ToString);

        end;
    except
      // PAIR not valid!!! Key not found...
    end;
    //
    //
    Memo1.Lines.Add('-----------------');
    //
    // walking on the road...
    for var O in jo do
      begin
        Memo1.Lines.Add('Object: ' + O.JsonString.ToString);
        //
        if O.JsonValue is TJSONArray then
          begin
            for var A in TJSONArray(O.JsonValue) do
              begin
                Memo1.Lines.Add('...Is an Array: ' + A.ToString);
                // ... recursive function here...
              end;
          end
        else // is an object... but... "if" is a array... needs a recursive too???
          begin
            Memo1.Lines.Add('...Not an Array is Object: ' + O.ToString);
          end;
      end;
  except
    // JSON not valid!!!
  end;
end;

 

Edited March 8, 2023 by programmerdelphi2k

[aehimself 388]

TJSONObject(TJSONObject(TArrayElement).GetValue('type')).GetValue<String>(message, messagestring);
TJSONObject(TArrayElement).GetValue<Integer>('time', timeinteger);
TJSONObject(TArrayElement).GetValue<String>('flex', flexboolean);

 

Also, don't forget to wrap the inner code in a Try...Finally block so you free JSONValue no matter what.