Button not displaying in LinearLayout

The problem was you were setting android:layout_width="fill_parent" for the TextView, so it took full screen width just for displaying the TextView. And it was not able to display the Button.

Here are two options for you :

1. Adding TextView and Button on a single row.

   Change the layout_width attribute of the TextView to wrap_content.

2. Adding TextView and Button vertically.

   Change LinearLayout's orientation attribute to vertical.

Try this.

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout android:id="@+id/LinearLayout01"
        android:layout_width="fill_parent" android:layout_height="45dip"
        xmlns:android="http://schemas.android.com/apk/res/android">
        <TextView android:layout_width="wrap_content"
            android:layout_height="45dip" android:paddingLeft="5dip"
            android:paddingRight="5dip" android:textStyle="bold" android:textSize="17dip"
            android:gravity="center_vertical" android:id="@+id/tvChild"
            android:text="Children" android:textColor="#ffCCCC22"
            />
            <Button android:id="@+id/submit"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_alignParentBottom="true"
                android:text="Submit" />
    </LinearLayout>

Use android:layout_width="wrap_content" instead of android:layout_width="fill_parent" for TextView and Button