add row in inline grid with other data as read only

You will first need to decide how your interface will tell the difference between "just added" items in the Data Array, versus ones that were already there.  Perhaps the prior data has a primary key, and the new row does not?  In this case, your row elements can simply determine whether the row data has a blank primary key, and set read-only to TRUE only in these cases.

Thank you , do you have any reference which i can use ?

I'm not exactly clear on what you still need, but it's all in the Appian documentaton.

a!localVariables(
  local!data: {
    {id: 1, field: "test1"},
    {id: 2, field: "test2"}
  },
  a!gridLayout(
    headerCells: {a!gridLayoutHeaderCell(label: "Test")},
    totalCount: count(local!data),
    rows: a!forEach(
      items: local!data,
      expression: a!gridRowLayout(
        id: fv!index,
        contents: {
          a!textField(
            value: local!data[fv!index].field,
            saveInto: local!data[fv!index].field,
            readOnly: not(isnull(local!data[fv!index].id))
          )
        }
      )
    ),
    addRowLink: aa!dynamicLink(
      label: "Add Row",
      value: {},
      saveInto: a!save(local!data,append(local!data,{id: null, field: null}))
    )
  )
)

FWIW, I believe (at least in a big picture / code readability sense) it's better to use "fv!item" rather than "local!data[fv!index]" to address array fields.  Sorry if this seems overly picky

a!textField(
  value: fv!item.field,
  saveInto: fv!item.field,
  readOnly: not(isnull(fv!item.id))
)

thank you guys ,i got you point .

Totally correct sir!  That was a quick-and-dirty

a!localVariables(
  local!data: {
    {id: 1, field: "test1"},
    {id: 2, field: "test2"}
  },
  a!gridLayout(
    headerCells: {a!gridLayoutHeaderCell(label: "Test")},
    totalCount: count(local!data),
    rows: a!forEach(
      items: local!data,
      expression: a!gridRowLayout(
        id: fv!index,
        contents: {
          a!textField(
            value: fv!item.field,
            saveInto: fv!item.field,
            readOnly: not(isnull(fv!item.id))
          )
        }
      )
    ),
    addRowLink: aa!dynamicLink(
      label: "Add Row",
      value: {},
      saveInto: a!save(local!data,append(local!data,{id: null, field: null}))
    )
  )
)