[android] How to add a button dynamically in Android?

In mainactivity.xml write:

<Button
    android:id="@+id/search"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Search" 
    android:visibility="invisible"/>

In main.java write:

Button buttonSearch;
buttonSearch = (Button)findViewById(R.id.search);
buttonSearch.setVisibility(View.VISIBLE);