How to create custom Material Dialog
<p>I would like to know how to create custom material dialog for my application. Specifically, I need to achieve something like this</p>

<p><a href="https://i.stack.imgur.com/1yO6y.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/1yO6y.png" alt="Material Dialog"></a></p>

<p>I have been following old method like this way:</p>

<pre><code>final Dialog dialog = new Dialog(context);
dialog.setContentView(R.layout.custom);
dialog.setTitle("Sample");
Button dialogButton = (Button) dialog.findViewById(R.id.dialogButtonOK);
            // if button is clicked, close the custom dialog
            dialogButton.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                    dialog.dismiss();
                }
            });
</code></pre>

<p>However, I got null pointer exception while tapping the <code>button</code>. Any tutorial will be also a great help for me.</p>