Mobile Applications
(Android Programming)
Semester II
2016 - 2017
Dr. Saman Mirza Abdullah
Class Objective
• The objective of this class is:
o To learn how Android applications store and access important resources
such as strings, graphics, and other data.
o To learn how to organize Android resources within the project files.
o To learn the localization and configuration of different devices.
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Resources Directory
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Resources and Codes
• Good developers not put data within the source
code.
• Instead, data are accessed programmatically.
• Storing application resources in a single place
o Is a more organized approach to development,
o Makes the code more readable and maintainable
o Localization (adaption) of applications for different languages and
devices.
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Resources
• All Android application are composed of two
things:
• Functionalities:
o Is a code that determines the behaviors of the application, such
algorithms or models for problems.
• Resources:
o They are data or information accessed by the source code, such as string,
style and themes, dimensions, image and icons, audio files, vedios, and
other data.
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Storing Resources
• Resources are separately stored from .java class files
• They are stored in XML, but still row data and graphs
are accepted.
• They are stored in /res directory
o File names should be lowercase.
o No duplicated.
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Resource Directories
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Resource Type and File
Hierarchy
http://d.android.com/guide/topics/resources/available-resources.html
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Default VS Alternative
Resources
• There are many criterion for storing resources.
o Default resources are those that stored automatically by the created
applications.
o Creating some special resources are needed in some cases:
• Internationalization, when an application needed to work with multilanguages.
• Localization, when there is a need to run an application smoothly on
different devices and orientations.
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Alternative Resources:
Examples
• An application with different graphical size.
/res/drwable-ldpi/mylogo.png (low-density screen)
/res/drwable-mdpi/mylogo.png (medium-density screen)
/res/drwable-hdpi/mylogo.png (high-density screen)
/res/drwable-xhdpi/mylogo.png (extra high-density screen)
/res/drwable-xxhdpi/mylogo.png (extra extra high-density screen)
• Application for different orientations:
/res/layout-port/main.xml (layout loaded in portiere)
/res/layout-land/main.xml (layout loaded in landscape)
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Access Resources
• All resource files will be compiled and seen as
R.Java class file and it is sub-classes.
• The file will be automatically generated when any
resources are added.
• Through this files the content is accessed.
• Example:
o A String named strHello defined within the resource file called
/res/values/string.mls
o Can be accessed R.string.strHellow  doesn't return data.
o String mystring = getResource().getString (R.String.strHello)
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Accessing Resource
Programmatically
• Using String resources programmatically:
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String Resources
• Using Bold, Italic, and underline.
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Working with Images
• Applications often include visual elements such as
icons and graphics.
• Android supports several image formats.
• can be directly included as resources for your
application.
• All resource filenames must be lowercase and
simple
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List of Image Formats
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Accessing Image Resource
• Image resources are simply another kind of
Drawable called a BitmapDrawable.
• For Accessing, mostly it needs only the resource ID
of the image.
• It can be accessed directly using BitmapDrawable
function.
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Color State List
• Some time it needs to color an object based on
state of the object.
• Could be done by special recourse called selector.
• Example:
o A Button control may need to by gray when disable, green when
activated, and yellow when processed.
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Color State List
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Color State Defining
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Button State Color
• we define a Button and set the textColor
• the state list resource file text_color.xml is defined as
list of state color.
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Class End
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