android: How to make the button transparent and have background color

Using XML
If you want to set color and along with that if you want to set transparent then you have to use that color code .

android:color="#66FF0000"    // Partially transparent red
android:alpha="0.25"         // 25% transparent 

Using java
And if you want to set dynamically (java code)then try this,

myButton.getBackground().setAlpha(64);  // 25% transparent

- i.e .INT ranges from 0 (fully transparent) to 255 (fully opaque)


Reference- http://stackoverflow.com/questions/20743124/setting-transparency-to-buttons-in-android