THIS IS A BAD IDEA 
Within callbacks it is very unhealthy (semantically wrong) to create hostaccess objects (MR_HostObject). “GetByIndex” is an example of creating a MR_HostObject, that must be done outside the callbacks. We have to implement a kind of “alarm”-system for those cases I’m afraid. Of cause that’s our fault and not yours.
Shift buttons are best adapted by using a SubPageArea + two SubPages. It is again a bit counter-intuitive, but works. That way when press+hold the shift button, the SubPage “Shift” is activated and by using “mapToValueRange(1, 0)” you can react on releasing the shift button, it inverts the internal process value.
var knob = deviceDriver.mSurface.makeKnob(0, 0, 2, 1)
var shiftButton = deviceDriver.mSurface.makeButton(2, 0, 2, 1)
var subPageAreaFunctionMode = page.makeSubPageArea('Function Mode')
var subPageFuncModMain = subPageAreaFunctionMode.makeSubPage('Main')
var subPageFuncModShift = subPageAreaFunctionMode.makeSubPage('Shift')
var selectedtrackChannel = page.mHostAccess.mTrackSelection.mMixerChannel
// if NOT SHIFTED control the selected track volume
page.makeValueBinding(knob.mSurfaceValue, selectedtrackChannel.mValue.mVolume)
.setSubPage(subPageFuncModMain)
// if SHIFT IS ACTIVE control the selected track pan
page.makeValueBinding(knob.mSurfaceValue, selectedtrackChannel.mValue.mPan)
.setSubPage(subPageFuncModShift)
// if NOT SHIFTED and shift button is pressed down, activate sub page 'Shift'
page.makeActionBinding(shiftButton.mSurfaceValue, subPageFuncModShift.mAction.mActivate)
.setSubPage(subPageFuncModMain)
// if SHIFT IS ACTIVE and shift button is released, activate sub page 'Main'
page.makeActionBinding(shiftButton.mSurfaceValue, subPageFuncModMain.mAction.mActivate)
.mapToValueRange(1, 0) // handle value inverted to react on releasing the button
.setSubPage(subPageFuncModShift)
Hi @axeleon, can you please add the label “midi-remote” to this topic as well?
yeah, i’ve also had weird loops 
That code was an example just to understand how to force a value, I understood from this thread that I have to use the CustomValueVariable
That is correct. However you can make the callbacks be per-page. I have done this in TypeScript because I get confused with all the procedural abstraction. I just can’t abide. But you can work it out I suppose.
I seriously don’t know how people keep things strait without OO abstraction. It creates really messy and hard to understand code, and when you come back to it after a week it’s even more difficult than the first time around.
I’m really hoping for Either TypeScript or even ES6 in the future.
class EventManager {
pagename;
functorEventDisplayValueChange;
functorEventHostTitle;
functorEventProcessValueChange;
constructor(pagename) {
this.pagename = pagename;
this.functorEventDisplayValueChange = null;
this.functorEventHostTitle = null;
this.functorEventProcessValueChange = null;
}
}
abstract class PageAwareEncoder {
element;
eventManagers;
eventDisplayValueChangeRegistered;
eventHostTitleRegistered;
eventProcessValueChangeRegistered;
currentpage;
functorDisplayValueChange;
functorHostTitle;
functorProcessValueChange;
constructor() {
this.element = null;
this.eventManagers = {};
this.eventDisplayValueChangeRegistered = false;
this.eventHostTitleRegistered = false;
this.eventProcessValueChangeRegistered = false;
this.currentpage = "";
this.functorDisplayValueChange = null;
this.functorHostTitle = null;
this.functorProcessValueChange = null;
}
resetPage(name) {
this.currentpage = name;
this._setFunctorTitleChange();
this._setFunctorDisplayValueChanged();
this._setFunctorProcessValueChanged();
}
_getEventManager(pageName) {
var eventManager = this.eventManagers[pageName];
var isUndefined = "" + typeof eventManager;
if (isUndefined == "undefined") {
return null;
}
return eventManager;
}
_makeEventManagerIfNeeded(pageName) {
var eventManager = this._getEventManager(pageName);
if (null == eventManager) {
eventManager = new EventManager(pageName);
this.eventManagers[pageName] = eventManager;
}
return eventManager;
}
registerEventDisplayValueChange(pageName, functor){
var eventManager = this._makeEventManagerIfNeeded(pageName);
eventManager.functorEventDisplayValueChange = functor;
if( this.eventDisplayValueChangeRegistered == false) {
this.eventDisplayValueChangeRegistered = true;
this.element.mSurfaceValue.mOnDisplayValueChange =
function(activeDevice, valueString) {
this._handleDisplayValueChanged(activeDevice, valueString);
}.bind(this);
}
}
registerEventHostTitle(pageName, functor){
var eventManager = this._makeEventManagerIfNeeded(pageName);
eventManager.functorHostTitle = functor;
if( this.eventHostTitleRegistered == false) {
this.eventHostTitleRegistered = true;
this.element.mSurfaceValue.mOnTitleChange =
function (activeDevice, value, units) {
this._handleTitleChange(activeDevice, value, units);
}.bind(this);
}
}
registerEventProcessValueChange(pageName, functor){
var eventManager = this._makeEventManagerIfNeeded(pageName);
eventManager.functorProcessValueChange = functor;
if( this.eventProcessValueChangeRegistered == false) {
this.eventProcessValueChangeRegistered = true;
this.element.mSurfaceValue.mOnProcessValueChange =
function(activeDevice, value) {
this._handleProcessValueChanged(activeDevice, value);
}.bind(this);
}
}
_setFunctorTitleChange() {
this.functorHostTitle = null;
var eventManager = this._getEventManager(this.currentpage);
if(null != eventManager) {
this.functorHostTitle = eventManager.functorHostTitle;
}
}
_setFunctorDisplayValueChanged(){
this.functorDisplayValueChange = null;
var eventManager = this._getEventManager(this.currentpage);
if(null != eventManager) {
this.functorDisplayValueChange = eventManager.functorEventDisplayValueChange;
}
}
_setFunctorProcessValueChanged(){
this.functorProcessValueChange = null;
var eventManager = this._getEventManager(this.currentpage);
if(null != eventManager) {
this.functorProcessValueChange = eventManager.functorProcessValueChange;
}
}
_handleTitleChange(activeDevice, value, units) {
if(null != this.functorHostTitle) {
this.functorHostTitle(activeDevice, value, units);
}
}
_handleDisplayValueChanged(activeDevice, valueString){
if(null != this.functorDisplayValueChange) {
this.functorDisplayValueChange(activeDevice, valueString);
}
}
_handleProcessValueChanged(activeDevice, value){
if(null != this.functorProcessValueChange) {
this.functorProcessValueChange(activeDevice, value);
}
}
}
Thank-you. This was very helpful. I was able to solve my problem for clearing pushencoder LEDs prior to shifting the bank left on my Mackie C4.
-Ron