main.xml

<?xml version="1.0" encoding="utf-8"?>
<TableLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
    <ListView android:layout_width="match_parent"
              android:layout_height="450dp"
              android:id="@+id/list_view"/>
    <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="0dip"
            android:layout_weight="1"
            android:gravity="center|bottom"
            android:orientation="vertical">
        <Button
                android:id="@+id/btn_data_inicial"
                android:layout_width="150dp"
                android:layout_height="60dp"
                android:layout_alignParentLeft="true"
                android:text="Data Inicial"
                android:background="#000000"
                android:textColor="#ff0000"
                />
        <ImageButton android:layout_width="70dp"
                     android:layout_height="60dp"
                     android:background="#000000"
                     android:textColor="#ffffff"
                     android:src="@android:drawable/ic_menu_search"
                     android:layout_toLeftOf="@+id/btn_data_final"
                     android:layout_toRightOf="@+id/btn_data_inicial"
                     android:id="@+id/btn_search"/>

        <Button
                android:layout_margin="0dp"
                android:id="@+id/btn_data_final"
                android:layout_width="150dp"
                android:layout_height="60dp"
                android:layout_alignParentRight="true"
                android:layout_marginRight="50dp"
                android:text="Data Final "
                android:background="#000000"
                android:textColor="#ff0000"
                />


    </RelativeLayout>

</TableLayout>