未定义的变量：Laravel

Im retrieving data from database into my Laravel admin panel, but it says undefined variable in my view.

index.blade.php is located in admin folder inside view folder

index.blade.php

@extends('admin.layout.admin')
@section('content')
  <h3>Admin Panel</h3>

    <table class="table">

    <tbody>

        @foreach($pools as $pool)
            <tr>
                <td>{{$pool->title}}</td>
                <td>Edit
                    |
                    Delete
                </td>
            </tr>
        @endforeach
    </tbody>
    </table>
@endsection

PoolDeisgnsController.php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Category;
use App\PoolDesign;

class PoolDesignController extends Controller
{
    /**
     * Display a listing of the resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function index()
    {
        $pools = PoolDesign::all();
        return view('admin.index', compact('pools'));
    }
}

PoolDesign.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;


class PoolDesign extends Model
{

    protected $fillable = ['title','description','area','depth','cost','image','category_id'];

    public function category(){
        $this->belongsTo(Category::class);
    }
}

It gives this error when executing

Undefined variable: pools (View: C:\xampp\htdocs\jayani_poolesources\views\admin\index.blade.php)

Routes

Route::get('/', function () {
    return view('welcome');
});

Route::get('/index','PagesController@index');
Route::get('/projects','PagesController@index1');
Route::get('/services','PagesController@index2');
Route::get('/blog','PagesController@index3');
Route::get('/about','PagesController@index4');
Route::get('/contact','PagesController@index5');

Auth::routes();
Route::get('/login','PagesController@login');

Route::get('/home', 'HomeController@index')->name('home');

Route::group(['prefix'=>'admin','middleware'=>'auth'], function(){
    Route::get('/', function(){
        return view('admin.index');
    })->name('admin.index');

    Route::resource('pools', 'PoolDesignController');
    Route::resource('category', 'CategoriesController');
});

With the url you are calling (/admin) you are executing the following piece of code:

Route::get('/', function(){
        return view('admin.index');
    })->name('admin.index');

Which will try to render admin.index without setting the pools variable, thus causing the error.

If you would navigate to /admin/pools it would be called correctly (i.e. through the controller, where the right variables are being set). You should change your routes accordingly or edit this piece of code to also provide $pools.

Or you could check in your template if $pools is set with:

@if(isset($pools))
   // Some more html here
@endif

It seems that your calling this route:

Route::group(['prefix'=>'admin','middleware'=>'auth'], function(){
    Route::get('/', function(){
        return view('admin.index');
    })->name('admin.index');

on your url. which really just direct your route to the view without going to the controller.

You can try this:

Route::group(['prefix'=>'admin','middleware'=>'auth'], function(){
    Route::get('/', function(){
        $pools = App\PoolDesign::all();
        return view('admin.index',compact('pools'));
    })->name('admin.index');