Nothing happens on back button click on Toolbar in Android
<p>When back button is clicked on the Toolbar nothing happens. I dont know whats the problem. </p>

<pre><code>toolbar = (Toolbar) findViewById(R.id.include);
    setSupportActionBar(toolbar);
    getSupportActionBar().setTitle("Notices For Students");
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    getSupportActionBar().setDisplayShowHomeEnabled(true);
</code></pre>