Function

a!signatureField( label, labelPosition, instructions, helpTooltip, target, fileName, fileDescription, value, saveInto, required, requiredMessage, buttonStyle, buttonSize, readOnly, disabled, validationGroup, accessibilityText, showWhen )

Allows users to capture and save a .png signature file. To upload signatures outside of a start form or task, use a!submitUploadedFiles() in the saveInto parameter of a submit button or link.

The signature field cannot upload multiple signature files or a pre-existing signature file.

Parameters

Usage considerations

Submitting the signature

After a user draws their signature, it is saved to a temporary folder. It is not saved to the target folder until it is submitted.

In start forms and tasks, on the button used to submit the form, make sure that the submit parameter set to true. When this button is clicked, the signature will be saved to the target folder.

Outside of start forms and tasks, use a!submitUploadedFiles() in the saveInto parameter of a button or link. This button or link could be used to submit the signature, as in this a!submitUploadedFiles() example, or the entire form, as in this example. When this button is clicked, the signature will be saved to the target folder.

Give end users Editor permissions to the target

In order to submit a signature, users must have at least Editor permissions to the target folder or document. For portals, give the portal service account Editor permissions to the target folder or document.

Any issue with creating or updating the target folder or document will cancel the signature submission and display an error.

Avoid saving unnecessary signatures

In a start form or task

For a start form or task, both the cancel and submit buttons will usually have the submit parameter set to true. As soon as one of these buttons are clicked, any signature that has been drawn will be saved to its destination.

To avoid saving a signature from a canceled form, configure the cancel flow in the process model to delete the unnecessary signature file.

Outside of a start form or task

If you are using the signature component outside of a start form or task, use a!submitUploadedFiles() in the saveInto parameter of a button or link. Do not use it in the signature component's saveinto parameter. This ensures that the signature is only saved to the target when the user is ready to submit it.

See a!submitUploadedFiles() for more information.

For portals, test the signature upload in a published portal

To make sure signature files will be uploaded correctly in a portal, publish the portal and test it on the portal website. The signature may seem to submit correctly when you test it in the interface object, but it may not work in the portal itself. For example, if the portal service account doesn't have Editor permissions to the target folder, you will see an error in the portal, but not in the interface object.

See a!submitUploadedFiles() for more information on testing and troubleshooting signature uploads in portals.

Saving a task as a draft with a signature

If a user has uploaded a signature to a task, they won't be able to save the task as a draft unless it is an offline-enabled task that they are viewing on Appian Mobile. They can remove the signature to save the task as a draft.

Signatures are stored as temporary documents until submission

Between drawing the signature and submitting it, the signature file is an inactive temporary document and not accessible.

If a signature is uploaded but never submitted, the temporary file is automatically deleted after 30 days.

File names

By default, the signature file uses the time stamp of when the signature was captured as a file name. You can define a custom file name in the fileName parameter. Check out the Signature upload in a start form or task example to see a custom file name in use.

If any of the following characters appear in a signature's file name, they are replaced by underscores: \ / " ; : | ? ' < > *.

Examples

To experiment with examples, copy and paste the expression into an interface object.

Signature upload in a start form or task

This example shows how to use the signature component in an interface that will be used in a start form or task.

Keep in mind that if you don't use this interface in a start form or task, on the submit button, you would need to replace submit: true with saveInto: a!submitUploadedFiles(). See Signature upload outside of a start form or task for more information.

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a!localVariables(
  local!signature,
  a!formLayout(
    label: "Signature Form",
    instructions: "Use this example in a start form or task",
    contents: {
      a!signatureField(
        label: "Signature",
        labelPosition: "ABOVE",
        /* The file name and description are used for the uploaded signature file */
        fileName: loggedInUser() & "_signature_" & today(),
        fileDescription: loggedInUser() & "'s signature on " & today(),
        /* Replace this with a constant of type Folder in your environment */
        target: cons!FOLDER_CONSTANT,
        value: local!signature,
        saveInto: local!signature
      )
    },
    buttons: a!buttonLayout(
      primaryButtons: {
        a!buttonWidget(
          label: "Submit",
          style: "SOLID",
          loadingIndicator: true,
          /* If you don't set the submit parameter to true, the signature will not be uploaded */
          submit: true
        )
      },
      secondaryButtons: {
        a!buttonWidget(
          label: "Cancel",
          value: true,
          saveInto: {},
          submit: true,
          style: "OUTLINE",
          validate: false
        )
      }
    )
  )
)

Displays the following:

Signature upload outside of a start form or task

This example shows how to use the signature component outside of a start form or task using a!submitUploadedFiles() in the saveInto parameter of a button. See a!submitUploadedFiles() for more examples.

Keep in mind that if you use this interface in a start form or task, on the submit button you would need to replace saveInto: a!submitUploadedFiles() with submit: true. See Signature upload in a start form or task for more information.

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a!localVariables(
  local!signature,
  local!submissionSuccessful,
  local!errorCode,
  {
    a!signatureField(
      label: "Signature",
      value: local!signature,
      saveInto: local!signature,
      /* Replace this with a constant of type Folder in your environment */
      target: cons!FOLDER_CONSTANT,
    ),
    a!buttonArrayLayout(
      buttons: {
        a!buttonWidget(
          label: "Submit",
          style: "SOLID",
          /* If you don't use a!submitUploadedFiles(), the signature will not be uploaded */
          saveInto: a!submitUploadedFiles(
            onSuccess: a!save(local!submissionSuccessful, true),
            onError: {
              a!save(local!submissionSuccessful, false),
              a!save(local!errorCode, fv!error)
            }
          )
        )
      },
      align: "END"
    )
  }
)

Displays the following:

Feature compatibility