android - Align radio buttons inside RadioGroup -

i have 4 radio buttons, , want align them both horizontally , vertically. i've tried drag them in androidstudio, won't let me drag them position want.

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/test_activity_layout" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingbottom="@dimen/activity_vertical_margin" android:paddingleft="@dimen/activity_horizontal_margin" android:paddingright="@dimen/activity_horizontal_margin" android:paddingtop="@dimen/activity_vertical_margin" android:weightsum="1" tools:context="com.aruffolo.quiz.testactivity">  <textview     android:id="@+id/test_activity_text"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:text="@string/test_activity_msg" />  <textview     android:id="@+id/questiontext"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:layout_below="@+id/test_activity_text"     android:layout_centerhorizontal="true"     android:layout_margintop="86dp"     android:text="medium text"     android:textappearance="?android:attr/textappearancemedium" />  <radiogroup     android:layout_width="500dp"     android:layout_height="250dp"     android:layout_weight=".07"     android:gravity="center"     android:id="@+id/radiogroup"     android:layout_below="@+id/questiontext">       <radiobutton         android:id="@+id/radiobutton2"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:text="new radiobutton"         android:layout_gravity="left|top"         android:layout_marginleft="5dp"/>      <radiobutton     android:id="@+id/radiobutton"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:text="new radiobutton"     android:layout_gravity="right|top"     android:layout_marginright="5dp"    />      <radiobutton     android:id="@+id/radiobutton4"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:text="new radiobutton"         android:layout_gravity="bottom|left"         android:layout_marginleft="5dp"/>  <radiobutton     android:id="@+id/radiobutton3"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:text="new radiobutton"     android:layout_gravity="bottom|right"     android:layout_marginright="5dp"/>  </radiogroup> 

here how looks like:

the top , bottom buttons should aligned horizontally.

please chenge code this:

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:tools="http://schemas.android.com/tools"     android:id="@+id/test_activity_layout"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:paddingbottom="@dimen/activity_vertical_margin"     android:paddingleft="@dimen/activity_horizontal_margin"     android:paddingright="@dimen/activity_horizontal_margin"     android:paddingtop="@dimen/activity_vertical_margin"     android:weightsum="1"     tools:context="com.aruffolo.quiz.testactivity">      <textview         android:id="@+id/test_activity_text"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:text="test_activity_msg" />      <textview         android:id="@+id/questiontext"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_below="@+id/test_activity_text"         android:layout_centerhorizontal="true"         android:layout_margintop="86dp"         android:text="medium text"         android:textappearance="?android:attr/textappearancemedium" />      <radiogroup         android:layout_width="500dp"         android:layout_height="250dp"         android:layout_weight=".07"         android:layout_centervertical="true"         android:layout_centerhorizontal="true"       android:gravity="center_horizontal|center_vertical"         android:id="@+id/radiogroup"         android:layout_below="@+id/questiontext">  <linearlayout     android:layout_width="wrap_content"     android:layout_height="wrap_content">         <radiobutton             android:id="@+id/radiobutton2"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:text="new radiobutton"              android:layout_marginleft="5dp"/>          <radiobutton             android:id="@+id/radiobutton"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:text="new radiobutton"              android:layout_marginright="5dp"    /> </linearlayout>         <linearlayout             android:layout_width="wrap_content"             android:layout_height="wrap_content">         <radiobutton             android:id="@+id/radiobutton4"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:text="new radiobutton"              android:layout_marginleft="5dp"/>          <radiobutton             android:id="@+id/radiobutton3"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:text="new radiobutton"              android:layout_marginright="5dp"/> </linearlayout>     </radiogroup>     </relativelayout>