listselect

control

Syntax	Description
ls.enter(list,callback)	Invokes `listselect` with the stated arguments. `list` is the list which will be selected from in `listselect`. `callback` requires a function which will take the selected item from `listselect` : function

example

listselect = require('listselect')
musicutil = require('musicutil')

function init()
  -- listselect used in params
  params:add_trigger('select_note','select fav note',1)
  params:set_action('select_note', function() listselect.enter(note_list,callback_note) end)

  -- defines the lists that we will be selecting from

  note_list = musicutil.NOTE_NAMES -- this is equivalent to note_list = {"C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B"}, but we can borrow lists from elsewhere

  -- listselect only takes a 1-d table
  -- if we want to use a more complex set of data, we have to extract what we want from it to make a list
  -- in the following, we extract only the names of scales from musicutil.SCALES

  scale_list = {} -- create a scale name table
  for i,v in ipairs(musicutil.SCALES) do -- typical Lua idiom
    scale_list[i] = musicutil.SCALES[i].name -- extract the name of each scale and add it to our 1-d table
  end

end

function callback_scale(selected_scale) -- this defines the callback function that is used in our KEY 3 listselect
  if selected_scale ~= 'cancel' then -- if an item is selected in listselect
    fav_scale = selected_scale
  end
  redraw()
end

function callback_note(selected_note) -- this defines the callback function that is used in our PARAMETERS-based listselect
  if selected_note ~= 'cancel' then -- if an item is selected in listselect
    fav_note = selected_note
  end
  redraw()
end

function redraw()
  screen.clear()
  screen.level(15)

  screen.move(0,10)
  screen.text('my favorite note is:')
  screen.move(0,20)
  if fav_note == nil then
    screen.text('select in params')
  else
    screen.text(fav_note)
  end

  screen.move(0,30)
  screen.text('my favorite scale is:')
  screen.move(0,40)
  if fav_scale == nil then
    screen.text('press K3 to select')
  else
    screen.text(fav_scale)
  end
  
  screen.update()
end

function key(n,z)
  if n == 3 and z == 1 then  
    listselect.enter(scale_list,callback_scale) -- when we press KEY 3, we enter listselect
  end
end

description

listselect provides a standard interface for navigating through a list and selecting a desired item. It returns the item selected from the list as a string. If no item is selected, then it returns cancel. It can be used in params (see fav_note in the example above) or in the script (see fav_scale above). It is used in various norns system menus, like WIFI.

Note that listselect only takes a “list”, that is, just a 1-dimensional series of entries like {'monday', 'tuesday', 'wednesday'} and not an array like:

{
  {day = 'monday', weather = 'good'},
  {day = 'tuesday', weather = 'fair'},
  {day = 'wednesday', weather = 'bad'}
}

Note also that listselect provides its own handlers for screen redraw, encoders, and keys. listselect automatically redraws the screen when its .enter function is invoked. K3 becomes ENTER, K2 becomes BACK. If K2 is pressed, listselect will exit and return to your script’s UI with its own redraw.