AlphaAnimation does not work

The problem is in android:alpha="0". This property sets transparency of a View http://developer.android.com/reference/android/view/View.html#attr_android:alpha

When alpha property is equal to 0 then animation is changing transparency from 0*0.0f=0 to 0*1.0f=0. When alpha property is set to 1 then animation is changing transparency from 1*0.0f=0 to 1*1.0f=1. That's why in first case you can't see text and in the second everything works as expected.

To make things work you have to set visibility property to invisible in layout xml. And before starting alpha animation call tv.setVisibility(View.VISIBLE);

More simple way is presented in this answer:

tv.animate().alpha(1).setDuration(1000);