MainTrackList

context.mainTrackList is the track-list surface used for selection and track creation workflows. Also accessible as context.trackList (same object reference).

Available in performEdit (TrackEdit context) only.

Properties

Property	Type	Writable	Example	Description
numSelectedTracks	number	No	1	Number of currently selected tracks.
numTracks	number	No	3	Total number of tracks in the project.

Methods

Method	Returns	Parameters	Description
expandAll(expand, recursive)	—	expand (boolean, req): true = expand, false = collapse. recursive (boolean, req): true = apply to nested folders.	Expands or collapses all folder tracks.
getInsertPosition()	number	(none)	Returns the track insert position. Returns a valid index when a track is selected, -1 when no track is selected.
getTrack(index)	object	index (number, req): Track index.	Returns the track at the given index. See Track Object.
getSelectedTrack(index)	object	index (number, req): Selected-track index.	Returns the selected track at the given index. See Track Object. Same object as getTrack(index) for the same track.
selectTrack(track, addToSelection, exclusive)	—	track (object, req): A track object. addToSelection (boolean, opt): true = add to selection, false = deselect. exclusive (boolean, opt): true = unselect others first.	Selects or deselects a track. Accepts 1 arg (track only) to select exclusively, or 2-3 args for fine control.
unselectAll()	—	(none)	Clears the track selection.

Track Creation Pattern

context.mainTrackList provides the insertion index. musicPartFunctions (see functions) creates the folder and child tracks, then moveToFolder(parentFolder, track, childIndex) moves the child track into the folder.

include_file("resource://{main}/sdk/engine.js");

var root = context.functions.root;
var musicPartFunctions = root.createFunctions("MusicPartFunctions");

var trackFormat = Host.Engine.TrackFormats.findEqual("Instrument");
var insertIndex = context.mainTrackList.getInsertPosition();

musicPartFunctions.executeImmediately = true;

var folderTrack = musicPartFunctions.addTrack(
  Engine.JS.kClassFolderTrack,
  insertIndex,
  "Folder"
);

var childTrack = musicPartFunctions.addMediaTrack(
  insertIndex + 1,
  "Child",
  trackFormat
);

musicPartFunctions.moveToFolder(folderTrack, childTrack, 0);