How to set several artLayers as activeLayer at the same time?

[Curvin]

Now I know several artLayers，and I want to set them as activeLayer at the same time. But one artLayer can be set as activeLayer when I use app.activeDocument.activeLayer

help~help~help~ 

[SuperMerlin]

activeLayer means ONE layer only!

You can have several layers selected  but activeDocument.activeLayer will return details of the top most selected layer.

[Curvin]

SuperMerlin, Thank you for your reply!

So we can not select several layers with code? Now I want to select several layers and merge them with code.

[SuperMerlin · Accepted solution]

You can select layers by Index , Id or by Name

Or select all layers.

Here are some functions that will let you do all the options including the merge.

function selectLayerByIndex(index,add){ 
var ref = new ActionReference();
ref.putIndex(charIDToTypeID("Lyr "), index);
var desc = new ActionDescriptor();
desc.putReference(charIDToTypeID("null"), ref );
if(add) desc.putEnumerated( stringIDToTypeID( "selectionModifier" ), stringIDToTypeID( "selectionModifierType" ), stringIDToTypeID( "addToSelection" ) ); 
desc.putBoolean( charIDToTypeID( "MkVs" ), false ); 
try{
executeAction(charIDToTypeID("slct"), desc, DialogModes.NO );
}catch(e){}
};
function selectLayerById(id,add){ 
var ref = new ActionReference();
ref.putIdentifier(charIDToTypeID("Lyr "), id);
var desc = new ActionDescriptor();
desc.putReference(charIDToTypeID("null"), ref );
if(add) desc.putEnumerated( stringIDToTypeID( "selectionModifier" ), stringIDToTypeID( "selectionModifierType" ), stringIDToTypeID( "addToSelection" ) ); 
desc.putBoolean( charIDToTypeID( "MkVs" ), false ); 
try{
executeAction(charIDToTypeID("slct"), desc, DialogModes.NO );
}catch(e){}
};
function selectLayerByName(lyrName,add){ 
add = undefined ? add = false:add 
var desc = new ActionDescriptor(); 
var ref = new ActionReference(); 
ref.putName( charIDToTypeID( "Lyr " ), lyrName); 
desc.putReference( charIDToTypeID( "null" ), ref ); 
if(add) desc.putEnumerated( stringIDToTypeID( "selectionModifier" ), stringIDToTypeID( "selectionModifierType" ), stringIDToTypeID( "addToSelection" ) ); 
desc.putBoolean( charIDToTypeID( "MkVs" ), false ); 
executeAction( charIDToTypeID( "slct" ), desc, DialogModes.NO ); 
};
function selectAllLayers() {
var desc29 = new ActionDescriptor();
var ref23 = new ActionReference();
ref23.putEnumerated( charIDToTypeID("Lyr "), charIDToTypeID("Ordn"), charIDToTypeID("Trgt") );
desc29.putReference( charIDToTypeID("null"), ref23 );
executeAction( stringIDToTypeID("selectAllLayers"), desc29, DialogModes.NO );
};
function mergeSelected() {
try{
executeAction( charIDToTypeID('Mrg2'), undefined, DialogModes.NO );
}catch(e){}
};

[Curvin]

Thank  you, got it!

[MBA-2-rae]

To select several layers with code I use this function, where the layer-IDs to be selected are stored in an array.

// layers to be selected (convert layer index to id:

id1 = getLayerId(activeDocument.layers[0])  //

id2 = getLayerId(activeDocument.layers[2])

// add more IDs if wanted

// store the layer-IDs into an array:

ary = [id1, id2]

// call the function

ret = selectLyr()

function selectLyr(lyrAry) {

    ////////////////////////////////////////////////////////

    // Description: Selects multiple layers

    // Parameters: lyrAry (Array):  Contains the layer-IDs to be  selected

    //  Return: boolean

    ////////////////////////////////////////////////////////

    if (lyrAry==undefined || lyrAry.constructor != Array )  return  false

    var d = new ActionDescriptor();

    var r = new ActionReference();

    for (var i = 0; i < lyrAry.length; i++) {       

        r.putIdentifier( s2t( "layer" ), lyrAry ) ;                         // Array of layer by ID

    }

    d.putReference( c2t( "null" ), r );

    d.putEnumerated( s2t( "selectionModifier" ), s2t( "selectionModifierType" ), s2t(  "addToSelection") );

    d.putBoolean( s2t( "makeVisible" ), true );

    try {executeAction( s2t( "select" ), d, DialogModes.NO ); return true;}

    catch(e) { return false }

}

function getLayerId(theLayer){

    // by mike hale, via paul riggott;

    // http://forums.adobe.com/message/1944754#1944754

    app.activeDocument.activeLayer = theLayer;      // theLayer must be object

    //Assumes activeDocument and activeLayer  

    var r = new ActionReference();

    r.putEnumerated(c2t("Lyr "), c2t("Ordn"), c2t("Trgt"));

    d = executeActionGet(r);

    return d.getInteger( c2t('LyrI') );

};

function c2t (s) {return app.charIDToTypeID(s)};

function s2t (s) {return app.stringIDToTypeID(s)};

[Curvin]

As we all know, we can select several layers in the PS panel, but can we select several layers with code?

And now I have gotten several layers .