Introduction to Forms
Form support of PSPDFKit
PSPDFKit supports all form types specified by the PDF specification. We have to differentiate between the field objects and the annotation objects.
| Type | Field Object | Annotation Object |
|---|---|---|
| Check, Radio and Pushbuttons | PSPDFButtonFormField |
PSPDFButtonFormElement |
| List and Comboboxes | PSPDFChoiceFormField |
PSPDFChoiceFormElement |
| Text | PSPDFTextFormField |
PSPDFTextFieldFormElement |
| Digital Signatures | PSPDFSignatureFormField |
PSPDFSignatureFormElement |
Retrieving Field and Annotation objects
Using the PSPDFFormParser (which can be retrieved from a PSPDFDocument or a PSPDFDocumentProvider) you can fetch either the field objects or annotation objects using the formFields or forms property.
If you need to retrieve a specific field or annotation object, you can use the methods findAnnotationWithFieldName: and findFieldWithFullFieldName:.
Field objects
The field objects handle the state of the form field and offer appropriate methods to modify the form field. Each form field has a fullyQualifiedName that can be used to identify and retrieve a specific field object.
You can query the type property to find out which kind of field object it is. This allows you to easily cast the PSPDFFormField to the right type.
Annotation objects
Each field object has one or more annotations linked to it. The main purpose of the annotation object is to offer a graphical element on top of the PDF (see Introduction to Annotations).
JavaScript support
PSPDFKit has limited support for executing JavaScript attached to the document, annotations and especially forms. Most validation rules should work out-of-the-box, and we're constantly working on improving the engine and increasing our coverage of the specifications.
Renaming form field names
Form field names can't be renamed using a PSPDFFormField or PSPDFFormElement instance, due to internal constraints. It is, however, possible to rename them using the PSPDFProcessor. See formFieldNameMappings. You can simply pass in a dictionary containing your source form field name and the new form field name.
As an example, this can be useful if you have a template PDF with form fields that needs to be appended to a different PDF file. Form field names must be unique and it would not be possible to append the same template multiple times without changing the names.
Please note, this requires the Document Editor component to be enabled for your license.
