Magento 2: What is purpose of StateInterface & when to use?

Question

In vendor\magento\module-contact\Controller\Index\Post.php

They are using \Magento\Framework\Translate\Inline\StateInterface $inlineTranslation

$this->inlineTranslation->suspend();
$this->inlineTranslation->resume();

When is the purpose, options & when I have to use in my Custom Post form & where?

Answer 1

Those functions are set/change the status of In-line translation.

public function suspend($status = false)
{
    if ($this->storedStatus === null) {
        $this->storedStatus = $this->isEnabled;
        $this->isEnabled = $status;
    }
}


public function resume($status = true)
{
    $this->isEnabled = !$status ? $status : $this->storedStatus;
    $this->storedStatus = null;
}

If the in-line translation is allowed or is set true public function isAllowed() string will translated accordingly.