Custom 'dynamic' form field creation

Question

I tried to look around, but didn't exactly found what I was looking for. Joomla have documentation about how to create custom form fields. That was useful, but what I need is (I guess simple..?).

I want to have custom form field for backend component. Just a simple input text field with two options - add/delete. When you press add I get additional text field, if I want to delete - it simply removes. I want to understand how to do this. Thank you!

Answer 1

I am using the following to achieve something similar to what you need BUT in a plugin. Need to confirm if it is also valid to component.

            <field
                name="list_field_name"
                type="list"
                class="inputbox"
                label="LIST_FIELD_NAME_LABEL"
                description="LIST_FIELD_NAME_DESC"
                default="add"
                size="1">
                <option value="add">add</option>
                <option value="delete">delete</option>
            </field>
            <field
                name="text_field_name"
                type="text"
                class="inputbox"
                showon="list_field_name:add"
                label="TEXT_FIELD_NAME_LABEL"
                description="TEXT_FIELD_NAME_DESC"
                size="40"
                filter="string" />

The use of showon let you conditionally show the field. Hope it helps.

Answer 2

From my experience. onshow ONLY works if you use renderFieldSet if you use renderField it won't work. it seems that the whole fieldset needs to be shown at the same time so that JForm can link the fields.

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Content transferred from deleted answer (deleted via moderation) by @robjoyce:

Correction to my previous:
renderField works too. It's when you use the label and value separately that it will break.

[grammar/formatting improved by @mickmackusa]