How to check if webview YouTube video player was started

The communication between webview and native are done through JavascriptInterface. YouTube has built it's API in a similar fashion. you can use the below code to achieve what you want.

To achieve the play/pause functionality via Youtube video you can use YouTube JavaScript Player API.

Example:

<div id="video-placeholder"></div>

<script src="https://www.youtube.com/iframe_api"></script>

When the API is fully loaded, it looks for a global function called onYouTubeIframeAPIReady() which you should define.

Your code should look something like this

var player;

function onYouTubeIframeAPIReady() {
    player = new YT.Player('video-placeholder', {
        width: 600,
        height: 400,
        videoId: 'Xa0Q0J5tOP0',
        playerVars: {
            color: 'white',
            playlist: 'taJ60kskkns,FG0fTKAqZ5g'
        },
        events: {
            onReady: initialize
        }
    });
}

Just make two buttons and call the needed method on click.

$('#play').on('click', function () {
    player.playVideo();
});

$('#pause').on('click', function () {
    player.pauseVideo();
});

You can use JavascriptInterface to get the callback inside the native java/kotlin code from WebView.

More details info

1. Youtube javascript player API with example

2. JavaScript Interface with example