Android Layout left and right align in horizontal layout

Use...

 <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"
    android:weightSum="1.0" >

<ImageView
    android:id="@+id/imageView1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="left"
    android:layout_marginRight="80dp"
    android:layout_weight="0.5"
    android:gravity="left"
    android:src="@drawable/ic_launcher" />

<ImageButton
    android:id="@+id/terminateSeed"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_weight="0.5"
    android:gravity="right"
    android:layout_marginLeft="80dp"
    android:background="@null"
    android:src="@drawable/ic_launcher" />
</LinearLayout>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:src="@drawable/ic_launcher" />

    <Button
        android:id="@+id/button1"
        style="?android:attr/buttonStyleSmall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true"
        android:text="Button" />

</RelativeLayout>

Use This example if you want to use LinearLayout without giving Weight

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="left"
       />

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        android:gravity="right"
        />
    </LinearLayout>