On-tap event not working in android

I’ve build an android app using ionic.

The app is working fine on other android devices but i checked it on mi(xiaomi) phones. My app’s first screen contains login with facebook, login with google and skip login button. i added on-tap event on all three of them and neither of those are working in mi phones.

<section class="paddingh40 margint10">
    <button class="button button-block facebook fg-white no-border" style="background-color:#3B5998;" on-tap="fblogin();">Sign in with Facebook</button>
    <button class="button button-block marginb0 googleplus fg-white no-border" style="background-color:#d34836;" on-tap="gPluslogin();">Sign in with Google</button>

    <p class="md-captionx text-center no-margin paddingv10 fg-grayLight" style="font-size: 0.8rem;"><small>We never post unless you tell us to</small></p>
</section>

<section>
    <div class="text-center pos-absx full-size paddingh40">
        <div class="bd-top-lighter">
        <button class="button-clear no-margin paddingt5 button-small md-body-1 button-block text-center fg-dark" on-tap="skipLogin();">
            Skip Login
        </button>
        </div>
    </div>
</section>

What can be the reason behind it ?