Exports first-level layers and layer groups to png images for Android (ldpi, mdpi, hdpi, xhdpi).

photoshop-export-layers-android.jsx

#target photoshop

function main(){
    if(!documents.length) 
        return;

    // suppress all dialogs
    app.displayDialogs = DialogModes.NO;
    var mainDoc = app.activeDocument;
    var docFullName = mainDoc.fullName;
    var docPath = mainDoc.path;
    // get file name without extension
    var docName = mainDoc.name.replace(/\.[^\.]+$/, '');
    
    var dpiNames = ["ldpi", "mdpi", "hdpi", "xhdpi"];
    var dpiCoefs = [0.375, 0.5, 0.75, 1];
    //var dpiCoefs = [0.666666, 1, 1.5, 2];

    for (var i = 0; i < dpiNames.length; i++) {
        mainDoc.resizeImage(mainDoc.width * dpiCoefs[i], mainDoc.height * dpiCoefs[i], undefined, ResampleMethod.BICUBIC);
        var dpiName = dpiNames[i];
        var workingPath = docPath + "/" + docName + "/" + dpiName;
        new Folder(workingPath).create();
        //savePSD(mainDoc, workingPath + "/" + dpiName + "-" + mainDoc.name);
        exportLayersToPSD(mainDoc, workingPath);
        mainDoc.close(SaveOptions.DONOTSAVECHANGES);
        mainDoc = app.open(File(docFullName));
    }
};

function savePSD(workingDoc, saveFile){
    var psdOpts = new PhotoshopSaveOptions();
    psdOpts.embedColorProfile = true;
    psdOpts.alphaChannels = true;
    psdOpts.layers = true;
    psdOpts.spotColors = true;
    workingDoc.saveAs(new File(saveFile), psdOpts, false, Extension.LOWERCASE); 
};

function savePNG(workingDoc, saveFile){
    var pngOpts = new ExportOptionsSaveForWeb; 
    pngOpts.format = SaveDocumentType.PNG
    pngOpts.PNG8 = false; 
    pngOpts.transparency = true; 
    pngOpts.interlaced = false; 
    pngOpts.quality = 100;
    workingDoc.exportDocument(new File(saveFile), ExportType.SAVEFORWEB, pngOpts); 
};

function exportLayersToPSD(originalDoc, path) {  
    function scanLayers(el, path) {

        // process layer sets (groups)
        for(var i = 0; i < el.layerSets.length; i++){
            var layer = el.layerSets[i];
            if (!layer.visible)
                continue;
            saveLayer(layer, path);
        }

        // process plain layers
        for(var j = 0; j < el.artLayers.length; j++) {
            var layer = el.artLayers[j];
            if (!layer.visible)
                continue;
            saveLayer(layer, path);
        }
    };

    function saveLayer(layer, path) {
        // create temporary document with same size as original and transparent fill
        var workingDoc = app.documents.add(originalDoc.width, originalDoc.height, originalDoc.resolution, originalDoc.name + " copy", NewDocumentMode.RGB, DocumentFill.TRANSPARENT);
        try {        
            // duplicate work only for active document
            app.activeDocument = originalDoc;
            layer.duplicate(workingDoc);
            //merge work only for active document
            app.activeDocument = workingDoc;
            workingDoc.trim(TrimType.TRANSPARENT,true,true,true,true);
            workingDoc.mergeVisibleLayers();
            workingDoc.trim(TrimType.TRANSPARENT,true,true,true,true);
            savePNG(workingDoc, File(path + "/" + layer.name + ".png"));
        }
        catch(e) {
        }
        // close temporary document
        workingDoc.close(SaveOptions.DONOTSAVECHANGES);
    };
    
    scanLayers(originalDoc, path);
};

main();