PHP - Laravel Request::all() should no be called statically

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;

use Illuminate\Support\Facades\Redirect;

use App\Http\Requests;

use App\Http\Requests\ArticuloFormRequest;

use App\Articulo;

use DB;

class ArticuloController extends Controller

{

    public function __construct()

    {

    }

    public function index(Request $request)

    {

        if ($request)

        {

            $query=trim($request->get('searchText'));

            $articulos=DB::table('articulo as a')

            ->join('categoria as c','a.idcategoria','=','c.idcategoria')

            ->select('a.idarticulo','a.nombre','a.codigo','a.stock','c.nombre as categoria','a.descripcion','a.imagen','a.estado')

            ->where('a.nombre','LIKE','%'.$query.'%')

            ->orwhere('a.codigo','LIKE','%'.$query.'%')

            ->orderBy('idarticulo','desc')

            ->paginate(7);

            return view('almacen.articulo.index',["articulos"=>$articulos,"searchText"=>$query]) ;

        }

    }

    public function create()

    {

        $categorias=DB::table('categoria')

        ->where('condicion','=','1')

        ->get();

        return view("almacen.articulo.create",["categorias"=>$categorias]);

    }

    public function store(ArticuloFormRequest $request)

    {

        $articulo = new Articulo;

        $articulo->idcategoria = $request->get('idcategoria') ;

        $articulo->codigo      = $request->get('codigo') ;

        $articulo->nombre      = $request->get('nombre') ;

        $articulo->stock       = $request->get('stock') ;

        $articulo->descripcion = $request->get('descripcion') ;

        $articulo->estado      = "Activo" ;

        if (Request::HasFile('imagen')) {

            $file = Request::File('imagen');

            $file->move( public_path().'/imagenes/articulos/' , $file->getClientOriginalName() ) ;

            $articulo->imagen = $file->getClientOriginalName() ;

        }

        $articulo->save();

        return Redirect::to('almacen/articulo');

    }

    public function show($id)

    {

        return view('almacen.articulo.show',["articulo"=>Articulo::FindOrFail($id)]);

    }

    public function edit($id)

    {

        $articulo = Articulo::FindOrFail($id);

        $categorias = DB::table('categoria')

        ->where('condicion','=','1')

        ->get();

        return view("almacen.articulo.edit",["articulo"=>$articulo,"categorias"=>$categorias]);

    }

    public function update(ArticuloFormRequest $request,$id)

    {

        $articulo->idcategoria = $request->get('idcategoria') ;

        $articulo->codigo      = $request->get('codigo') ;

        $articulo->nombre      = $request->get('nombre') ;

        $articulo->stock       = $request->get('stock') ;

        $articulo->descripcion = $request->get('descripcion') ;

        if (Request::HasFile('imagen')) {

            $file = Request::File('imagen');

            $file->move( public_path().'/imagenes/articulos/' , $file->getClientOriginalName() ) ;

            $articulo->imagen = $file->getClientOriginalName() ;

        }

        $articulo->update() ;

        return Redirect::to('almacen/articulo');

    }

    public function destroy($id)

    {

        $articulo=Articulo::FindOrFail($id);

        $articulo->estado="Inactivo" ;

        $articulo->update();

        return Redirect::to('almacen/articulo');

    }

}