<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#cccccc" >

    <Button 
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button1"
        />
    
    <Button 
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button2"
        />
    
    <Button 
        android:id="@+id/button3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button3"
        />

</LinearLayout>

 

 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#ff0000" >
    
    <LinearLayout 
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="100px"
        android:background="#00ff00">
        
		<Button
	        android:id="@+id/bitton1"
	        android:layout_width="wrap_content"
	        android:layout_height="wrap_content"
	        android:text="Button1" />
            
    </LinearLayout>

	<LinearLayout 
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="100px"
        android:background="#0000ff">
        
		<Button
	        android:id="@+id/bitton2"
	        android:layout_width="wrap_content"
	        android:layout_height="wrap_content"
	        android:text="Button2" />
		
    </LinearLayout>

</LinearLayout>