android:backgroundTint="#80FFFFFF"
android:backgroundTintMode="src_over"
>>for setting background as transparent in android studio(only bg)
android:alpha="0.4"
>>for all viewsandroid:background="#55000000" //Black transparent
android:background="#00000000" //Transparent 100% — FF
95% — F2
90% — E6
85% — D9
80% — CC
75% — BF
70% — B3
65% — A6
60% — 99
55% — 8C
50% — 80
45% — 73
40% — 66
35% — 59
30% — 4D
25% — 40
20% — 33
15% — 26
10% — 1A
5% — 0D
0% — 00
yourView.setBackgroundColor(Color.TRANSPARENT);<android.support.v7.widget.CardView
xmlns:card_view="http://schemas.android.com/apk/res-auto"
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/myCardView"
android:layout_width="match_parent"
android:layout_height="match_parent"
card_view:cardBackgroundColor="@android:color/transparent"
card_view:cardElevation="0dp">