Add disabled button color

codec2talkie/src/main/res/color/btn_ptt_selector.xml

@@ -2,5 +2,6 @@
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
     <item android:state_focused="true" android:color="@color/green" />
     <item android:state_pressed="true" android:color="@color/red" />
+    <item android:state_enabled="false" android:color="@color/grey" />
     <item android:color="@color/green" />
 </selector>

codec2talkie/src/main/res/values/colors.xml

@@ -9,4 +9,5 @@
     <color name="white">#FFFFFFFF</color>
     <color name="red">#E33B3B</color>
     <color name="green">#2C7F26</color>
+    <color name="grey">#808080</color>
 </resources>