LinearLayout in Android (Vertical, XML)

Reading this, you probably have a clue that LinearLayout lays out object linearly and can only have a vertical and horizontal layout, no diagonal layout.

Here is an example of a vertical LinearLayout:
(update: horizontal LinearLayout here)

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout android:id="@+id/LinearLayout01"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
>

  <Button android:id="@+id/RecordBtn"
    android:text="Record"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" >
  </Button>

  <Button android:id="@+id/PlayBtn"
    android:text="Play"
    android:layout_height="wrap_content"
    android:gravity="right"
    android:layout_width="fill_parent">
  </Button>

  <Button android:id="@+id/StopBtn"
    android:text="Stop"
    android:layout_height="wrap_content"
    android:layout_width="fill_parent"
    android:gravity="left">
  </Button>

  <Button android:id="@+id/PauseBtn"
    android:text="Pause"
    android:layout_height="wrap_content"
    android:layout_width="fill_parent">
  </Button>
</LinearLayout>

Quick Explanation:
There would be 4 buttons here, Record, Play, Stop and Pause, each one have its id and a wrap_content height, 3 of the buttons have fill_parent which mean fill up all spaces their width, gravity is text-align in css. See the picture below to better understand.

Further reading
LinearLayout in Hello View in Android

Update History
   Somewhere before 2012: Here is how you can set this as your layout in your java code

   Jan 17, 2012 - Visual Update