RelativeLayout Scrollable

ScrollView does not allow more than one direct child, that's why you getting error. So you try as follows:

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"  android:layout_width="fill_parent"        android:layout_height="fill_parent"><RelativeLayout  android:layout_width="fill_parent"  android:layout_height="fill_parent">         <Button        android:id="@+id/button1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentRight="true"        android:layout_alignParentTop="true"        android:text="Button" />    <TextView        android:id="@+id/textView1"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignParentLeft="true"        android:layout_below="@+id/button1"        android:text="TextView" />    <TextView        android:id="@+id/textView2"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignParentLeft="true"        android:layout_below="@+id/textView1"        android:text="TextView" />    <TextView        android:id="@+id/textView3"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignParentLeft="true"        android:layout_below="@+id/textView2"        android:text="TextView" />    <Button        android:id="@+id/button2"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentBottom="true"        android:layout_centerHorizontal="true"        android:layout_below="@+id/textView3"        android:text="Button" />     </RelativeLayout></ScrollView>

You cant put more than one widget in a scrollview. To this you have to wrap your widget with a view. like below

<ScrollView    android:layout_width="fill_parent"    android:layout_height="fill_parent" >    <RelativeLayout        android:layout_width="fill_parent"        android:layout_height="fill_parent" >        <Button            android:id="@+id/btnBrowser"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_centerVertical="false"            android:layout_marginTop="5dp"            android:text="Browser" >        </Button>        <TextView            android:id="@+id/txtAuthor"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_below="@+id/btnBrowser"            android:layout_marginLeft="20dp"            android:layout_marginTop="10dp"            android:text="Text"            android:textColor="#143781"            android:textSize="20dp"            android:textStyle="bold" >        </TextView>        <TextView            android:id="@+id/txtDate"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_below="@+id/txtAuthor"            android:layout_marginLeft="20dp"            android:layout_marginTop="5dp"            android:textColor="#8D89B3"            android:textSize="14dp" android:text="Text"            >        </TextView>        <TextView            android:id="@+id/txtTitle"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_below="@+id/txtDate"            android:layout_marginLeft="20dp"            android:layout_marginTop="5dp"            android:textColor="#000000"            android:textSize="14dp"            android:textStyle="bold" android:text="Text">        </TextView>        <TextView            android:id="@+id/txtMsg"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_below="@+id/txtTitle"            android:layout_marginLeft="20dp"            android:textColor="#000000"            android:textSize="14dp" android:text="Text">        </TextView>        <Button            android:id="@+id/btnReply"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_below="@+id/txtMsg"            android:layout_centerInParent="@+id/txtMsg"            android:layout_marginTop="20dp"            android:text="Reply" >        </Button>    </RelativeLayout></ScrollView>

You are adding scrollview inside relativelayout. You have to add Relativelayout inside scrollview to get results. and one more thing scrollview can contains only one child at a time so add relativelayout into scrollview and see the difference