update README

README.md

@@ -9,6 +9,7 @@ UndoBar was modified from Roman(@romannurik)'s undobar concept (https://code.goo
 ![UndoBar Sample](https://github.com/soarcn/UndoBar/blob/master/art/redo.png?raw=true)
 ![UndoBar Sample](https://github.com/soarcn/UndoBar/blob/master/art/refresh.png?raw=true)
 ![UndoBar Sample](https://github.com/soarcn/UndoBar/blob/master/art/customize.png?raw=true)
+![UndoBar Sample](https://github.com/soarcn/UndoBar/blob/master/art/material.png?raw=true)
 
 
 How to use this library
@@ -40,12 +41,12 @@ API
 - UndoBar provides 3 default styles. You can use them for different purposes like undo,refresh, or just use it as replacement of toasts.
 - UndoBar will switch to KitKat look and feel in API-19 target and after.
 - UndoBar will determine if tranlucent mode(4.4) is using and adjust its position.
-- You can overwrite style in your project to change the look and feel. For example, you can use following lines in your style.xml to always use KitKat style UndoBar.
+- You can set theme in your appliation to change the look and feel. For example, you can use following lines in your style.xml to always use material style UndoBar.
 
     ```xml
-    <style name="UndoBar" parent="UndoBarKitKat"/>
-    <style name="UndoBarMessage" parent="UndoBarMessageKitKat"/>
-    <style name="UndoBarButton" parent="UndoBarButtonKitKat"/>
+    <style name="MaterialTheme" parent="android:Theme.Light">
+        <item name="undoBarStyle">@style/UndoBarMaterialStyle</item>
+    </style>
     ```
 
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