我有两个类似的功能，一个输出改变而另一个没有

Question

This code uses html, php and laravel. The first one 'tk' doesn't change in value whatever i do. The second one 'ntk' does change the value but eventually my output on the webpage allways gives me checked checkboxes for some reason. Really hope someone could help me out because I really don't know how this is possible. Especially that when I enter false in $ntk than the checkbox stays unchecked.

Here's my form:

<?php
        $tk = Session::has('tk') ? Session::get('tk') : 1;
        var_dump($tk);
        if($tk == 1){
            $tk = 'true';
        } else {
            $tk = 'false';
        }
        $tk_name = 'tk: ';
        var_dump($tk_name);
        var_dump($tk);
        $ntk = Session::has('ntk') ? Session::get('ntk') : 0;
        var_dump($ntk);
        if($ntk == 1){
            $ntk = 'true';
        } else {
            $ntk = 'false';
        }
        $ntk_name = 'ntk: ';
        var_dump($ntk_name);
        var_dump($ntk);
    ?>
    {{ Form::open(array('url' => 'aanvullen')) }}
        <table>
            <tr>
                <td>
                    {{ Form::submit('Toepassen') }}
                </td>
                <td>
                    {{ Form::checkbox('tk', 1, $tk) }} Tijdkritisch (TK) <br>
                    {{ Form::checkbox('ntk', 1, $ntk) }} Niet-tijdkritisch (NTK)
                <td>
            </tr>
        </table>
    {{ Form::close() }}

Here's my controller code:

if(isset($_POST['tk']) )
    {
        $tk = $_POST['tk'];
        Session::put('tk', $tk);
    } else {
        $tk = 1;
        Session::put('tk', $tk);
    }

    if(isset($_POST['ntk']) )
    {
        $ntk = $_POST['ntk'];
        Session::put('ntk', $ntk);
    } else {
        $ntk = 0;
        Session::put('ntk', $ntk);
    }

Answer 1

You are using this:

if($tk == 1){
    $tk = 'true';
} else {
    $tk = 'false';
}

In this case, $tk is always true because true is String not a Boolean value and when you use $tk as Boolean value, it comes out to true because it's a truthy value, for example:

$tk = 'false';
echo !!$tk; // 1 = true

Anyways, that's the problem, your $tk contains a string not Boolean and the right way to assign a Boolean value is:

$k = TRUE; / without qoutes

But you don't have to assign TRUE or FALSE to $tk like this:

enter code hereif($tk == 1){
    $tk = true;
} else {
    $tk = false;
}

Since, 0 is a falsy value evaluates to FALSE and 1 evaluates to TRUE so you can directly use $tk like this:

{{ Form::checkbox('tk', 1, $tk) }}

Depending on the value (1 or 0) of $tk it would be either:

{{ Form::checkbox('tk', 1, 1) }} // Checked
{{ Form::checkbox('tk', 1, 0) }} // Unchecked

So, if the $tk contains 1 then the checkbox will be checked and if 0 then it won't be checked.