slide out animation not working on back press button?

I used slide_in.xml

    <?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="@android:integer/config_longAnimTime"
    android:fromXDelta="100%"
    android:toXDelta="0%" >

</translate>

slide_out.xml

    <?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="@android:integer/config_longAnimTime"
    android:fromXDelta="0%"
    android:toXDelta="-100%" >

</translate>

slide_enter.xml

  <?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="@android:integer/config_longAnimTime"
    android:fromXDelta="-100%"
    android:toXDelta="0%" >

</translate>

slide_exit.xml

    <?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="@android:integer/config_longAnimTime"
    android:fromXDelta="0%"
    android:toXDelta="100%" >

</translate>

Code

        Intent i=new Intent(Authentication.this,Login.class);
        startActivity(i);
        overridePendingTransition(R.anim.slide_in, R.anim.slide_out);

To previous

         finish();
         overridePendingTransition(R.anim.slide_enter, R.anim.slide_exit);

Add animation in onBackPressed, it will show the animation while clicking the back button.

@Override
public void onBackPressed() {
    super.onBackPressed();
    overridePendingTransition(R.anim.slide_in, R.anim.slide_out);   
}

Firstly create one more animation i.e nothing.xml in your anim folder

nothing.xml

<?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="@android:integer/config_longAnimTime"
    android:fromXDelta="0%"
    android:toXDelta="0%" >

</translate>

here is your slide_in.xml

<?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="@android:integer/config_longAnimTime"
    android:fromXDelta="-100%"
    android:toXDelta="0%" >

</translate>

and slide_out.xml

<?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="@android:integer/config_longAnimTime"
    android:fromXDelta="0%"
    android:toXDelta="100%" >

</translate>

Now call your NewActivity like this

startActivity(new Intent(CurrentActivity.this, NewActivity.class));
overridePendingTransition(R.anim.slide_in, R.anim.nothing);

and then on your back button click do this

finish();
overridePendingTransition(R.anim.nothing, R.anim.slide_out);