How to change Style of View in Android

How to change Style of View 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.
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:textColor">#456789</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.
• for getting more information regarding style attributes visit here.

• Now run the project you will see the following view.