Add this in xml
<?xml version="1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" >
<gradient android:endColor="@color/colorPrimary" android:startColor="@color/white" />
<corners android:radius="20dp"/> </shape>
or add this in .java file
View layout = findViewById(R.id.mainlayout);
GradientDrawable gd = new GradientDrawable( GradientDrawable.Orientation.TOP_BOTTOM, new int[] {0xFF616261,0xFF131313}); gd.setCornerRadius(0f);
layout.setBackgroundDrawable(gd);

Change the layout color dynamically
LinearLayout Layout = (LinearLayout) findViewById(R.layout.id); Layout.setBackgroundColor(Color.parseColor("#ffffff"));
Dynamically set the background color gradient
View layout = findViewById(R.id.mainlayout);
GradientDrawable gd = new GradientDrawable( GradientDrawable.Orientation.TOP_BOTTOM, new int[] {0xFF616261,0xFF131313}); gd.setCornerRadius(0f);
layout.setBackgroundDrawable(gd);