Detecting user clicks in PDF form elements on Android

With Nutrient, it’s possible to detect when a form element is clicked or selected for editing.

Reacting to clicks on form elements

The default on-click behavior of form elements depends on their type:

  • Taps on push buttons lead to an execution of the Action, which is set on the form element.

  • Taps on signature fields start the signing flow.

  • Taps on other fields lead to form element selection and entering the form editing mode.

Default tap behavior can be fully customized by registering OnFormElementClickedListener via addOnFormElementClickedListener() on PdfFragment:

fragment.addOnFormElementClickedListener { formElement ->
    when {
        formElement.type == FormType.SIGNATURE -> {
            // Implement custom signature flow here.
            ...

            // By returning `true`, you intercept the event and prevent PSPDFKit from showing the signature picker itself.
            true
        }
        formElement.type == FormType.PUSHBUTTON -> {
            // Implement custom push button click handling.
            ...

            // By returning `true`, you intercept the event and prevent PSPDFKit from executing the button's action.
            true
        }
        else -> {
            // This click event isn't interesting for us. Return `false` to let PSPDFKit handle this click event.
            false
        }
    }
}
fragment.addOnFormElementClickedListener(formElement -> {
    if (formElement.getType() == FormType.SIGNATURE) {
        // Implement custom signature flow here.
        ...

        // By returning `true`, you intercept the event and prevent PSPDFKit from showing the signature picker itself.
        return true;
    } else if (formElement.getType() == FormType.PUSHBUTTON) {
        // Implement custom push button click handling.
        ...

        // By returning `true`, you intercept the event and prevent PSPDFKit from executing the button's action.
        return true;
    }

    // This click event isn't interesting for us. Return `false` to let PSPDFKit handle this click event.
    return false;
});

Reacting to form element selection

Most form elements, with the exception of buttons and signature fields, can be selected for interactive editing. You can get notified about this via OnFormElementSelectedListener and OnFormElementDeselectedListener, both of which can be registered on PdfFragment.

Form selection also leads to entering the form element editing mode. You can react to its lifecycle by registering OnFormElementEditingModeListener on PdfFragment. If you want to learn more, refer to the custom form editing UI guide that describes how to use this listener to integrate Nutrient’s form filling UI when using custom activities built around PdfFragment.