adding a function on plugin file when a button is clicked [closed]

Question

lets say I have my main plugin file. mainpluginfile.php

I also have a function that is not yet included the file like,

function my_function_to_be_added(){

  echo 'hello this is a test';

}
add_action('wp_head','my_function_to_be_added');

SO how can I go about including the file when a click on something let say a button that I have in the admin page.

so that when I activate the plugin, this function does not exist until when I click the button that's when it is added into the plugin.

Is this accomplishable?

thanks.

Answer 1

As @toscho points out, the answer is: no, it is not acomplishable.

If you go the regular way, you'll have a checkbox in your plugin's page that, when enabled and the options are saved/updated, will activate the action hook.

Answer 2

go ahead and include the function in your mainpluginfile.php

then, add the action conditionally on if the button has been pressed.

if( get_option( 'some_option' ) ) add_action('wp_head','my_function_to_be_added');

bind your button to a function that updates the option.