Arranging radio buttons just below the text and perfectly in center for all android devices

Question

I want to Arrange radio butons just below the text but I am not able to do it. I have used android:layout_marginLeft="20dp" but it works for only particular device not for all.

<LinearLayout
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal" >

    <TextView
        android:id="@+id/txt1"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_weight="1"
        android:background="#ff0000"
        android:gravity="center"
        android:text="red" />

    <TextView
        android:id="@+id/txt2"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_weight="1"
        android:background="#00ff00"
        android:gravity="center"
        android:text="green" />

    <TextView
        android:id="@+id/txt3"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_weight="1"
        android:background="#0000ff"
        android:gravity="center"
        android:text="blue" />
</LinearLayout>

<RadioGroup
    android:id="@+id/rg_rgrp"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:weightSum="3" >

    <RadioButton
        android:id="@+id/rbtn_red"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_gravity="center"
        android:layout_weight="1"
        android:gravity="center" />

    <RadioButton
        android:id="@+id/rbtn_green"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_weight="1"
        android:gravity="center" />

    <RadioButton
        android:id="@+id/rbtn_blue"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_weight="1"
        android:gravity="center" />
</RadioGroup>

I have used Gravity and layout_gravity both but it works properly for text not for radio buttons.

Answer 1

Your RadioGroup should look like this. No code required.

<RadioGroup
    android:id="@+id/rg_rgrp"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal" >
    <View
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_weight="1" />
    <RadioButton
        android:id="@+id/rbtn_red"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="" />
    <View
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_weight="2" />
    <RadioButton
        android:id="@+id/rbtn_green"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="" />
    <View
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_weight="2" />
    <RadioButton
        android:id="@+id/rbtn_blue"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="" />
    <View
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_weight="1" />
</RadioGroup>