How to work with Style in android?

Styles in Android

Web Technology design comes with the concept of Styles and Themes. Styles like Cascading Style Sheets (CSS) define the values of the web controls attributes such as width, heigth, font color, background and so on. A style can be applied on several controls in several web pages.

A style is a collection of properties that specify the look and format for a View or window. A style can specify properties such as height, padding, font color, font size, background color, and much more. A style is defined in an XML resource that is separate from the XML that specifies the layout.Android allow you to define the look and feel, for example colors and fonts, of Android components in XML resource files. This way you have to set common style attributes only once in one central place.

Styles in Android share a similar philosophy to cascading stylesheets in web design—they allow you to separate the design from the content.

If the entry in the resource file is used to style a view, it is typically referred to as a style, while if it is used for styling an activity or application it is typically called a theme .

To define a style or a theme, save an XML file in the /res/values directory of your project. The root node of the XML file must be and you use a style tag that includes the name attribute. This tag contains than more or more item tags which define values for named attributes.

for example ....

Themes are used to group a set of styles to be applied on the whole web application. Themes (or sometimes skins) define the look of all control within the application.

Android introduces similar concepts by using Styles and Themes. A Style can be applied to views individually while a Theme is applied to a whole activity.

Styles:

Styles are defined as xml resources files in res/values directory of your project.You can add the Styles via coding or by graphical way.

here is the attributes that defines the TextView component or View. which define the layout width and hieght , text color , text , and background.

<textview    android:layout_width="match_parent"   
     android:layout_height="wrap_content"    
     android:textColor="#F0F"     
     android:text="Style Text"
     android:background="#0AF" 
     />

for the same result you can use the style.xml file which is under the res/values in your project , an you can create like this.

<?xml version="1.0" encoding="utf-8"?>
<resources>
<style name="myStyle">
<item name="android:layout_width">match_parent</item>
<item name="android:layout_height">wrap_content</item>
<item name="android:background">#0AF</item>
<item name="android:textColor">#F0F</item>
</style>
</resources>

Now you can use style in you TextView like following

<?xml version="1.0" encoding="utf-8"?>
<textview android:text="Style Text"
     style="@style/myStyle" / >

Using Themes

Now you can use styles as theme at the activity level or at the application level for giving an better interactive look to your application 

when you apply a theme on an activity level then all views or components or widgets within that activity will inherited from that theme.

for doing this, open the AndroidManifest.xml and go the  tag and add the android:theme attribute:

<?xml version="1.0" encoding="utf-8"?>
<activity android:name=".MyTheme"
                  android:label="@string/app_name" android:theme="@style/myStyle">

to apply a theme on the application level so that the style will be applied to all activities within your application, open the AndroidManifest.xml and go the  tag and add the android:theme attribute:

<?xml version="1.0" encoding="utf-8"?>
<application android:icon="@drawable/icon" android:label="@string/app_name" android:theme="@style/myStyle">

to set the theme of an activity programmatically call this line in the onCreate method

this.setTheme(R.style.BlueLabel);

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Nitendra Thakur

How to work with Style in android?

Styles in Android

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