Laravel view links and web.php routes messed up - php

Question

I'm making a forum with themes and topics. If a user clicks on a theme, he/she gets to see all the topics within that theme. Here we encounter the first problem. In the theme.blade.php I have a title: <span class="card-title">{{ $theme->theme_title }} - Topics</span>. This title is supposed to show the title of the theme that the user clicked on. But it shows (just a wild guess) some random theme title from the database that is not even connected to this topic.
Now I made an extra view for the user. If the user clicks on a topic from the selected theme. He/she is supposed to redirect to the topic that he/she clicked on but instead its shows (again) some random topic from the database that is not connected to the topic/theme at all. Instead of the topic that the user clicked on. In this GIF http://imgur.com/a/vOQFT you can see the problem If u look at the profile picture and username. Maybe the problem is in the Web.phpor somewhere else, I don't know. Sorry for the long story but I couldn't figure out how say this in a better way. I think I switched some things up in the code.
Here is the every file of code where this problem may occur
Web.php
Route::get('/', 'ThemesController#index')->name('home');
Route::get('/theme/{theme_id}/topics', 'ThemesController#show')->name('showtheme');
Route::get('/theme/{theme_id}/topics/{topic_id}', 'TopicsController#show')->name('showtopic');
Route::group(['middleware' => 'App\Http\Middleware\AdminMiddleware'], function() {
//THEMES
Route::get('/theme/{theme_id}/edit', 'ThemesController#edit')->name('edittheme');
Route::patch('/theme/{theme_id}/edit', 'ThemesController#update')->name('updatetheme');
Route::get('/theme/create', 'ThemesController#create')->name('createtheme');
Route::post('/theme/create', 'ThemesController#save')->name('savetheme');
Route::delete('/theme/{theme_id}/delete', 'ThemesController#destroy')->name('deletetheme');
//TOPICS
Route::get('/theme/{theme_id}/topics/{topic_id}/edit', 'TopicsController#edit')->name('edittopic');
Route::patch('/theme/{theme_id}/topics/{topic_id}/edit', 'TopicsController#update')->name('updatetopic');
Route::get('/theme/{theme_id}/topics/create', 'TopicsController#create')->name('createtopic');
Route::post('/theme/{theme_id}/topics/create', 'TopicsController#save')->name('savetopic');
Route::delete('/theme/{theme_id}/topics/{topic_id}/delete', 'TopicsController#destroy')->name('deletetopic');
});
Route::get('user/profile', 'UserController#profile')->name('showprofile');
Route::post('user/profile', 'UserController#update_avatar');
Theme.blade.php (The list of every topic within the theme)
<div class="col s12">
<div class="card">
<div class="card-content"><span class="card-title">{{ $theme->theme_title }} - Topics</span>
<div class="collection">
#foreach($topics as $topic)
<a href="{{ route('showtopic', ['theme_id' => $theme->id, 'topic_id' => $topic->id ]) }}" 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="card-title">{{ $topic->topic_title }}</span>
<p>{!! str_limit($topic->topic_text, $limit = 125, $end = '...') !!}</p>
</div>
</div>
<div class="row last-row">
<div class="col s12 post-timestamp">Posted by: {{ $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">{{ $topic->replies->count() }}</p>
</div>
<div class="col s2">
<h6 class="title center-align">Status</h6>
<div class="status-wrapper center-align"><span class="status-badge status-open">open</span></div>
</div>
<div class="col s2">
<h6 class="title center-align">Last reply</h6>
<p class="center-align"></p>
<p class="center-align">Tijd</p>
</div>
</div>
</a>
#endforeach
</div>
</div>
</div>
</div>
ThemesController.php (Only show method)
public function show($id)
{
$theme = Topic::find($id)->theme;
$topics = Theme::find($id)->topics;
return view('themes.theme')->with('topics', $topics)->with('theme', $theme);
}
TopicsController.php(Only show method)
public function show($id)
{
$theme = Theme::find($id);
$topic = Topic::find($id);
return view('topics.topic')->with('theme', $theme)->with('topic', $topic);
}
Thanks for looking at my code. This problem has been sitting here for quite a while and I want to move on. Thanks for your help!

Answer 1

Your controller code simply finds the theme with ID $id, and the topic (singular!) with ID $id. That particular topic may not appear in that particular theme at all. They likely have nothing to do with each other.
To find the topics belonging to the theme with ID $id, you would do this:
$theme = Theme::find($id)->with('topics');
(this assumes your model relationships are set up correctly, you have not show us those). See the docs on eager loading.
To access the topics in your view, do something like this:
#foreach ($theme->topics as $topic)
...
{{ $topic->user->username }}
...
While developing, you can simply
return $theme;
in your controller to see the structure of the data, so you can work out how to handle and iterate over it.