On click of a button , a check mark icon should be displayed on the leftmost corner of the button, when reclicked on the same button , the check mark icon should disppear. Could some on help me out in this case?
While this is already answered, here's an alternative solution: add a unicode checkmark symbol. There are two of them: \u2713 and \u2714. Just add them to your strings:
<string name="button_label_on">\u2713 on</string>
<string name="button_label_off">off</string>
Of course, you can put this directly into your layout code, too:
<Button
...
android:text="\u2713 on"
/>