I need to create an alpha-gradient on the edge of the ImageView. Preferably using only XML.
Need to code a custom ImageView if you want colorless transparency.
If your background is a static color, here's my preferred workaround:
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@drawable/your_image"/>
<item>
<shape android:shape="rectangle">
<gradient android:startColor="#00efefef"
android:endColor="#ffefefef"
android:angle="270"
android:type="linear"/>
</shape>
</item>
</layer-list>