Round corner button: Where am I wrong - android-layout

Question

I want to create round corner button. This is what I tried:
I have defined the button's background drawable button_bg.xml :
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item
android:state_enabled="false"
android:drawable="#color/grey">
<shape>
<solid
android:color="#ef4444" />
<stroke
android:width="1dp"
android:color="#992f2f" />
<corners
android:radius="16dp" />
</shape>
</item>
<item
android:state_pressed="true"
android:state_enabled="true"
android:drawable="#color/dark_grey"
>
<shape>
<solid
android:color="#ef4444" />
<stroke
android:width="1dp"
android:color="#992f2f" />
<corners
android:radius="16dp" />
</shape>
</item>
<item
android:state_enabled="true"
android:drawable="#color/blue"
>
<shape>
<solid
android:color="#ef4444" />
<stroke
android:width="1dp"
android:color="#992f2f" />
<corners
android:radius="16dp" />
</shape>
</item>
</selector>
Then, I apply it to my button in layout file:
<Button
android:text="#string/press_me"
android:layout_margin="12dp"
android:layout_width="fill_parent"
android:layout_height="30dp"
android:background="#drawable/button_bg"
/>
But my button is still showing sharp corner instead of the round one, why??
(Please don't just throw me a link about how to make round corner, my above code followed those tutorials, I just want to know where am I wrong. Thanks)

Answer 1

remove android:drawable from the item node have it like this.
<item android:state_pressed="true"
android:state_enabled="true">
EDIT : (How can I specify the color from colors.xml for item then?)
Create a stateful color drawable for your button text color.
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_focused="true" android:state_pressed="false" android:color="#ffffff" />
<item android:state_focused="true" android:state_pressed="true" android:color="#000000" />
<item android:state_focused="false" android:state_pressed="true" android:color="#000000" />
<item android:color="#ffffff" />
</selector>
and then set this as your text color for your button .
android:textColor="#drawable/button_text_color"

Answer 2

Remove all android:drawable from item as below then it will work.
When you add the attribute android:drawable in item then this drawable overlapped your created shape. That's why you can't see your rounded shape.
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_enabled="false"><shape>
<solid android:color="#ef4444" />
<stroke android:width="1dp" android:color="#992f2f" />
<corners android:radius="16dp" />
</shape></item>
<item android:state_enabled="true" android:state_pressed="true"><shape>
<solid android:color="#ef4444" />
<stroke android:width="1dp" android:color="#992f2f" />
<corners android:radius="16dp" />
</shape></item>
<item android:state_enabled="true"><shape>
<solid android:color="#ef4444" />
<stroke android:width="1dp" android:color="#992f2f" />
<corners android:radius="16dp" />
</shape></item>
</selector>