Error: com.tns.NativeScriptException: Failed to find module: "nativescript-drop-down/angular", relative to: app/tns_modules/

{
  "description": "sistema de picking Rahmati",
  "license": "SEE LICENSE IN <your-license-filename>",
  "readme": "NativeScript Application",
  "repository": "<fill-your-repository-here>",
  "nativescript": {
    "id": "org.adealoxica.picking",
    "tns-android": {
      "version": "5.2.1"
    }
  },
  "dependencies": {
    "@angular/animations": "^7.2.9",
    "@angular/common": "^7.2.9",
    "@angular/compiler": "^7.2.9",
    "@angular/compiler-cli": "^7.2.9",
    "@angular/core": "^7.2.9",
    "@angular/forms": "^7.2.9",
    "@angular/http": "^7.2.9",
    "@angular/platform-browser": "^7.2.9",
    "@angular/platform-browser-dynamic": "^7.2.9",
    "@angular/platform-server": "^7.2.9",
    "@angular/router": "^7.2.9",
    "nativescript-angular": "^7.2.3",
    "nativescript-drop-down": "^5.0.0",
    "nativescript-theme-core": "~1.0.2",
    "reflect-metadata": "^0.1.13",
    "rxjs": "^6.4.0",
    "rxjs-compat": "^6.4.0",
    "tns-core-modules": "^5.2.2",
    "zone.js": "^0.8.29"
  },
  "devDependencies": {
    "babel-traverse": "^6.26.0",
    "babel-types": "^6.26.0",
    "babylon": "6.4.5",
    "lazy": "1.0.11",
    "nativescript-dev-typescript": "^0.9.1-next-2019-03-12-162713-03",
    "typescript": "^3.1.6"
  },
  "name": "picking",
  "author": "Adealoxica"
}

import { Component, OnInit } from "@angular/core";
import { User } from "../../Model/User/user";
import {UserService} from "../../Model/User/user.service"
import { Page } from "tns-core-modules/ui/page";
import aplicacion = require("tns-core-modules/application");
import aplicacionSet=require("tns-core-modules/application-settings");
import { ModalDialogParams } from "nativescript-angular/modal-dialog";
import { SelectedIndexChangedEventData } from "nativescript-drop-down";

@Component({
    selector: "login",
    providers: [UserService],
    templateUrl: "./modal/login/login.html",
    styleUrls: ["./modal/login/login-common.css"]
})

export class ViewLogin implements OnInit {
    user: User;
    estadoLog="";
    clave="";

    loading=false;
    public selectedIndex=0;
    public dependientes: Array<string>=[];


    constructor(
        private params:ModalDialogParams,
        private userService:UserService,
        private page:Page)
    {
        console.log("entrando en login");
        this.user=new User(null);
        this.user.usuario="";
        this.user.clave="";
        this.userService.listar().subscribe(
        (res:Array<User>)=>{
             res.forEach(element => {
                 this.dependientes.push(element.usuario);
             });
             this.selectedIndex=0;
             console.log("ADENTRO DE LA FUNCION SUBSCRIBE ----- " + res.length);
            },
             (error)=>{
             console.log("Error al hacer LOGIN: " + error);
         });

         this.page.on("unloaded", () => {
             this.params.closeCallback(null);
             });
             console.log("DESPUES DEL page.on");
    }

    public onchange(args: SelectedIndexChangedEventData) {
        console.log('El usuario selecionado es ' + this.dependientes[args.newIndex] + " new-> " + args.newIndex + " select-> " + this.selectedIndex);
        this.user.usuario=this.dependientes[args.newIndex];
    }

    teclado(numero:string)
    {
        if(numero=='back')
            this.user.clave=this.user.clave.substring(0,this.user.clave.length-1);
        else
            this.user.clave+=numero;
        this.clave= Array(this.user.clave.length+1).join("*") ;
    }

    ngOnInit()
    {

        this.page.actionBarHidden=true;
        if(aplicacionSet.hasKey("usuario"))
            this.user.usuario=aplicacionSet.getString("usuario");

    }

    summit(){
        if(this.loading)
            return;
        this.loading=true;
        this.estadoLog="";
        var res=aplicacion.getResources();
        this.userService.login(this.dependientes[this.selectedIndex],this.user.clave).subscribe(
            (resultado:User)=>
                    {
                        if(resultado==null)
                            {
                                console.log("Login incorrecto: " + resultado);
                                this.estadoLog="Login incorrecto"
                                res["login"]=null;
                                aplicacion.setResources(res);
                                this.loading=false;
                                return false;
                            }
                        else
                            {
                                this.estadoLog="Login correcto";
                                res["login"]=resultado;

                                aplicacion.setResources(res);
                                aplicacionSet.setString("usuario",this.user.usuario);
                                console.log("lo hemos logrado: " + resultado.nombre);
                                console.log("login correcto");
                                this.params.closeCallback(resultado);
                                this.loading=false;
                                return true;
                            }
                    },
            (error)=>
                    {
                        console.log("No ha hecho login: " + error);
                        this.estadoLog = "Login incorrecto";
                        res["login"]=null;
                        aplicacion.setResources(res);
                        this.loading=false;
                        return false;
                    }
        );

    }

    volver()
    {
        this.params.closeCallback(null);
    }

}