How to create View partially invisible

Question

What I'd like to achieve is effect like the one in the picture:

So basically there's a TextView which slowly disappears. I don't want whole View to be made for example 50% transparent, but rather for example left part of it to be 0% transparent, and it smoothly goes into 100% transparency at the right side.

I know that some components (e.g. ListView) uses this, but is it possible to do it manually in quite easy way?

Thanks in advance for answers

Answer 1

First, create a shape with an alpha gradient. Place the XML into your drawable directory. Let's call it gradient_view.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <gradient
        android:angle="90"
        android:startColor="#FFFFFFFF"
        android:endColor="#00FFFFFF"
        android:type="linear"/>
</shape>

Now create a view in your layout to the right of your TextView. You'll need to set width and height appropriately and position in your view as required (RelativeLayout with layout_toTheRightOf would work well).

<View android:layout_width="100dp"
    android:layout_height="50dp"
    android:background="@drawable/gradient_view"/>

In the right place in your code, animate it. Change the -200 to whatever you need (or even better, find the left X of your gradient view and subtract the left edge of your TextView to find the amount to move).

TranslationAnimation anim = new TranslateAnimation(0, -200, 0, 0);
anim.setDuration(1000);
myTextView.startAnimation(anim);

http://developer.android.com/reference/android/view/animation/TranslateAnimation.html

There's a bit more work to do but this is most of what you need.

Good luck