Change UI elements by changing main.xml

In the previous article, "Exercise: Hello World with EditText input", all the elements are placed in a single LinearLayout, both the OK and Cancel button's width are defined as wrap_content. It can be noted that the layout is not good aligned.

The layout can be changed by changing main.xml, without any modification on the java code.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  >
<TextView
       android:layout_width="fill_parent"
       android:layout_height="wrap_content"
       android:text="@string/hello"
       />
<TextView
       android:layout_width="fill_parent"
       android:layout_height="wrap_content"
       android:text="Who you are?"
       />
<EditText
  android:id = "@+id/message_text"
       android:layout_width="fill_parent"
       android:layout_height="wrap_content"
       />
<Button
  android:id = "@+id/ok"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="OK" />
<Button
  android:id = "@+id/cancel"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="Cancel" />
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  >
<TextView
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="@string/hello"
  />
<TextView
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="Who you are?"
  />
<EditText
  android:id = "@+id/message_text"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  />
<LinearLayout
  android:orientation="horizontal"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  >
<Button
  android:id = "@+id/ok"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:text="OK" />
<Button
  android:id = "@+id/cancel"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:text="Cancel" />
</LinearLayout>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  >
<TextView
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="@string/hello"
  />
<TextView
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="Who you are?"
  />
<EditText
  android:id = "@+id/message_text"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  />
  <LinearLayout
         android:orientation="horizontal"
         android:layout_width="fill_parent"
         android:layout_height="fill_parent"
         android:gravity="right|bottom"
         >
         <Button
                android:id = "@+id/ok"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="OK" />
         <Button
                android:id = "@+id/cancel"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Cancel" />
  </LinearLayout>
</LinearLayout>

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