最后样式为：

布局文件：

                    <RadioGroup
                        android:layout_centerVertical="true"
                        android:layout_marginLeft="100dp"
                        android:id="@+id/radioGroup2"
                        android:layout_width="wrap_content"
                        android:layout_height="30dp"
                        android:checkedButton="@+id/radioButton2_1"
                        android:orientation="horizontal">
                        <RadioButton
                            android:id="@+id/radioButton2_1"
                            android:layout_width="wrap_content"
                            android:layout_height="match_parent"
                            android:button="@null"
                            android:checked="false"
                            android:drawableLeft="@null"
                            android:paddingLeft="10dp"
                            android:paddingRight="10dp"
                            android:text="万"
                            android:background="@drawable/selector_448ced_ffffff_corners_lefttop_leftbottom_4"
                            android:textColor="@drawable/selector_color_448ced_ffffff"
                            android:textSize="13sp" />
                        <RadioButton
                            android:background="@drawable/selector_ffffff_448ced_corners_righttop_rightbottom_4"
                            android:textColor="@drawable/selector_color_448ced_ffffff"
                            android:id="@+id/radioButton2_2"
                            android:layout_width="wrap_content"
                            android:layout_height="match_parent"
                            android:button="@null"
                            android:drawableLeft="@null"
                            android:paddingLeft="10dp"
                            android:paddingRight="10dp"
                            android:text="亿"
                            android:textSize="13sp" />
                    </RadioGroup>

selector_448ced_ffffff_corners_lefttop_leftbottom_4.xml:

<?xml version="1.0" encoding="utf-8"?>
<selector
xmlns:android="http://schemas.android.com/apk/res/android">
<item  android:drawable="@drawable/shape_solid_ffffff_corners_lefttop_leftbottom_4_1stroke448ced" android:state_checked="false" />
<item android:drawable="@drawable/shape_solid_448ced_corners_lefttop_leftbottom_4" android:state_checked="true"/>
</selector>

shape_solid_ffffff_corners_lefttop_leftbottom_4_1stroke448ced.xml

<?xml version="1.0" encoding="utf-8"?>
    <shape
    xmlns:android="http://schemas.android.com/apk/res/android">
    <solid
        android:color="#ffffff"/>
  <corners
      android:bottomLeftRadius="4dp"
      android:topLeftRadius="4dp"/>
    <stroke
        android:width="1dp"
        android:color="#448ced"/>

</shape>

shape_solid_448ced_corners_lefttop_leftbottom_4.xml

<?xml version="1.0" encoding="utf-8"?>
    <shape
    xmlns:android="http://schemas.android.com/apk/res/android">
    <solid
        android:color="#448ced"/>
  <corners
      android:bottomLeftRadius="4dp"
      android:topLeftRadius="4dp"/>

</shape>

selector_color_448ced_ffffff.xml

<?xml version="1.0" encoding="utf-8"?>
<selector
xmlns:android="http://schemas.android.com/apk/res/android">
<item  android:color="#448ced" android:state_checked="false" />
<item android:color="#ffffff" android:state_checked="true"/>
</selector>

selector_ffffff_448ced_corners_righttop_rightbottom_4.xml

<?xml version="1.0" encoding="utf-8"?>
<selector
xmlns:android="http://schemas.android.com/apk/res/android">
<item  android:drawable="@drawable/shape_solid_ffffff_corners_righttop_rightbottom_4_1stroke448ced" android:state_checked="false" />
<item android:drawable="@drawable/shape_solid_448ced_corners_righttop_rightbottom_4" android:state_checked="true"/>
</selector>

shape_solid_ffffff_corners_righttop_rightbottom_4_1stroke448ced.xml

<?xml version="1.0" encoding="utf-8"?>
    <shape
    xmlns:android="http://schemas.android.com/apk/res/android">
    <solid
        android:color="#ffffff"/>
  <corners
      android:bottomRightRadius="4dp"
      android:topRightRadius="4dp"/>
    <stroke
        android:width="1dp"
        android:color="#448ced"/>

</shape>

shape_solid_448ced_corners_righttop_rightbottom_4.xml

<?xml version="1.0" encoding="utf-8"?>
    <shape
    xmlns:android="http://schemas.android.com/apk/res/android">
    <solid
        android:color="#448ced"/>
  <corners
      android:bottomRightRadius="4dp"
      android:topRightRadius="4dp"/>

</shape>