<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="center_horizontal"> <ImageView android:id="@+id/qrCode" android:layout_width="350dp" android:layout_height="350dp" android:layout_marginTop="20dp" /> </LinearLayout>