Linearlayout in bottom of screen in android.

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

<LinearLayout 

xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="fill_parent"

    android:layout_height="wrap_content"

    android:background="#fff"
    android:layout_alignParentBottom="true" 

   android:orientation="vertical">

    <LinearLayout    

    android:layout_width="fill_parent"   

     android:layout_height="wrap_content"   

     android:orientation="horizontal">




    <LinearLayout       

 android:id="@+id/la2"     

   android:layout_width="fill_parent"    

    android:layout_height="35dp"      

  android:gravity="center"        android:layout_margin="5dip"    

    android:layout_weight="1"     

   android:orientation="vertical">
        <ImageView           

 android:id="@+id/couponimage"       

     android:layout_width="30dip"   

         android:layout_height="30dip"   

         android:src="@drawable/acc"            />

    </LinearLayout>


        <LinearLayout    

        android:id="@+id/lf0"       

     android:layout_width="fill_parent"    

        android:layout_height="wrap_content" 

           android:gravity="center"        

    android:layout_margin="5dip"        

    android:layout_weight="1"      

      android:layout_marginBottom="-50dp"          

  android:background="@drawable/foot_round_button" 

           android:orientation="vertical">
            <ImageView            

    android:id="@+id/search_badgess"            

    android:layout_width="30dip"          

      android:layout_height="30dip"                android:src="@drawable/search"
                />

        </LinearLayout>


        <LinearLayout         

   android:id="@+id/lo1"      

      android:layout_width="fill_parent"   

         android:layout_height="35dp"      

      android:gravity="center"          

  android:layout_margin="5dip"         

   android:layout_weight="1"          

  android:orientation="vertical">
            <ImageView              

  android:id="@+id/tableimage"       

         android:layout_width="30dip" 

               android:layout_height="30dip" 

               android:src="@drawable/setting"                />

        </LinearLayout>

    </LinearLayout>
</LinearLayout>