how to put the text on the left of a radio button in android

Try adding the following attributes into the RadioButton, it should work, this way you still get to keep the ripple effect on the radio button:

android:layoutDirection="rtl"
android:textAlignment="textStart"
android:layout_gravity="start"

Remember to set supportsRtl property to true in your application manifest.

for eg:

   <RadioGroup
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical" >

        <RadioButton
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="4dp"
            android:layoutDirection="rtl"
            android:textAlignment="textStart"
            android:layout_gravity="start"
            android:text="The test item a"
            android:textSize="14sp" />

         ....                       

    </RadioGroup>

would give out: