Learn How to Inherit Style properties in Android.

Learn How to Inherit Style properties in Android.

Style is a collection of property provides format and look to view or Window.Although style can done only to a particular view or window.However to apply same style to whole application or activity you need to use a theme.

Inheritence in Style allows to apply more attribute to the view.

Style in Android is defined in xml file name as style.xml different from the layout xml file.

So lets us learn how to apply style to a view.

• first start eclipse and select new-> file-> android application project.
• fill the android application project with the following details:
• Application name-StyleTheme
• Project name-StyleTheme
• Package name-style.theme
• Build SDK-4.1(API-16)

• Now open activity_main.xml file under res-> layout-> activity_main.xml you will see the given code.

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  
   xmlns:tools="http://schemas.android.com/tools"  
   android:layout_width="match_parent"  
   android:layout_height="match_parent" >  
   <TextView  
     android:layout_width="wrap_content"  
     android:layout_height="wrap_content"  
     android:layout_centerHorizontal="true"  
     android:layout_centerVertical="true"  
     android:text="@string/hello_world"  
     tools:context=".MainActivity" />  
 </RelativeLayout>  

• here we have defined properties for the text view individually .Instead of doing this we can use simply apply style for the view by writing these lines.

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  
   xmlns:tools="http://schemas.android.com/tools"  
   android:layout_width="match_parent"  
   android:layout_height="match_parent" >  
   <TextView  
    style="@style/myStyle"  
     android:text="@string/hello_world" />  
 </RelativeLayout>  

• Now we need to define the style which we have applied.so open the style.xml under res->layout -> values->style.xml. and we have defined here.

 <resources xmlns:android="http://schemas.android.com/apk/res/android">  
   <style name="AppTheme" parent="android:Theme.Light" />  
   <style name="myStyle" parent="@android:style/TextAppearance">  
     <item name="android:layout_width">fill_parent</item>  
     <item name="android:layout_height">wrap_content</item>  
     <item name="android:textSize">42dp</item>  
      <item name="android:background">#abcdef</item>  
   </style>  
 </resources> 

• parent attributes in<style> element we have used for inheriting the style attributes.
• <item> elements is used to redefine the properties according to the requirement of view.
• When we will Run this output is :

• Now we will use inheritance to style by adding more properties to style but here we don't need a Parent keyword in <style> attribute.so style.xml will look like this

 <resources xmlns:android="http://schemas.android.com/apk/res/android">  
   <style name="AppTheme" parent="android:Theme.Light" />  
   <style name="myStyle" parent="@android:style/TextAppearance">  
     <item name="android:layout_width">fill_parent</item>  
     <item name="android:layout_height">wrap_content</item>  
    <item name="android:background">#abcdef</item>  
     <item name="android:textSize">42dp</item>  
      </style>  
   <style name="myStyle.Red">  
     <item name="android:textColor">#FF0000</item>  
   </style>  
 </resources>  

• And to use this attribute we need to change the style of activity_main.xml under res->layout->activity_main.xml.

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  
   xmlns:tools="http://schemas.android.com/tools"  
   android:layout_width="match_parent"  
   android:layout_height="match_parent" >  
   <TextView  
    style="@style/myStyle.Red"  
     android:text="@string/hello_world" />  
 </RelativeLayout>  

• Now when we run this project you will see following change:

• For getting more information regarding style attributes visit here.