Laravel foreach database issue - php

Question

I am making a forum and when the user clicks on a theme, a page shows up with every topic that belongs to that theme. The problem is, how do I do this?
I made a for each loop which shows ALL the topics from the database instead of the topics that belong to that theme I clicked on. How can I do this?
Web.php
Route::get('/', 'ThemesController#index')->name('home');
Route::get('/theme/{id}', 'ThemesController#show')->name('showtheme');
ThemesController.php
I only show the show method because I believe that's the only one necessary here
public function show($id)
{
$topics = Topic::all($);
return view('themes/topics')->with('topics', $topics);
}
topics.blade.php
#extends('layouts.default')
#section('content')
<div class="container main-content">
<div class="row first-row">
<div class="col s12">
<div class="card">
<div class="card-content clearfix">Nieuw topic</div>
</div>
</div>
<div class="col s12">
<div class="card">
<div class="card-content"><span class="card-title"> - Topics</span>
<div class="collection">
#foreach($topics as $topic)
<a href="" class="collection-item avatar collection-link"><img src="/uploads/avatars/{{ $topic->user->avatar }}" alt="" class="circle">
<div class="row">
<div class="col s6">
<div class="row last-row">
<div class="col s12"><span class="title">Theme - {{ $topic->topic_title }}</span>
<p>{!! str_limit($topic->topic_text, $limit = 100, $end = '...') !!}</p>
</div>
</div>
<div class="row last-row">
<div class="col s12 post-timestamp">Gepost door: {{ $topic->user->username }} op: {{ $topic->created_at }}</div>
</div>
</div>
<div class="col s2">
<h6 class="title center-align">Replies</h6>
<p class="center replies">{{ $topic->replies->count() }}</p>
</div>
<div class="col s2">
<h6 class="title center-align">Status</h6>
<div class="status-wrapper center-align"><span class="status-badge status-open">open</span></div>
</div>
<div class="col s2">
<h6 class="title center-align">Laatste reply</h6>
<p class="center-align">Naam</p>
<p class="center-align">Tijd</p>
</div>
</div>
</a>
#endforeach
</div>
</div>
</div>
</div>
<div class="col s12">
<div class="card">
<div class="card-content clearfix">Nieuw topic</div>
</div>
</div>
</div>
</div>
#endsection
I believe I'm doing something obviously wrong but I can't see what.
Help will be appreciated. Thanks in advance
If I miss some code, Please inform me.

Answer 1

How are you defining the relationship between a theme and it's topics? You'll have to have something like a one to many or many to many established in your database for you to be able to query correctly. Do you have anything like that yet?
****edit****
public function show($id)
{
$topics = Theme::find($id)->topics;
return view('themes/topics')->with('topics', $topics);
}