Transparency color with Android

How to get a transparency color in your Android Layout (or View) ?

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:background="#FFFFFF"

    android:padding="5dp"

    android:fitsSystemWindows="true"

    android:id="@+id/scrollview1">

In the sample just above the background color is white and not transparent.

To transform this color like a transparent color, do like that :

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:background="#80FFFFFF"

    android:padding="5dp"

    android:fitsSystemWindows="true"

    android:id="@+id/scrollview1">

Put the value 80 before the color !

Simple is Androïd.