Technical Blog of Android

  main.xml  <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:layout_width="fill_parent"     android:layout_height="fill_parent" android:orientation="vertical" android:layout_gravity="center"> <TextView     android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:text="@string/hello"     android:gravity="center" android:textSize="25sp"/> <Button android:text="Scan QR Code" android:id="@+id/scanner" android:layout_width="wrap_content" android:layout_height="wrap_content" android:gravity="center" android:layout_gravity="center_horizontal"></Button> <Button android:text="Scan BAR Code" android:id="@+id/scanner2" android:layout_width="wr...