Post on 14-May-2022
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Islamic University of Gaza
Faculty of Engineering
Computer Engineering Department
Mobile Computing ECOM 5341
By
Eng. Wafaa Audah
July 2013
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Creating Applications and
Activities
Aapplication creation steps and settings
Fill:
Application and
Package Names
>> Next
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This frame gives
you different
features and
choices for
launcher icon
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Complete “Hello World” application is created successfully!
Fill:
Activity Name
>> Finish
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Project structure
src
User specified java source code files will be available here.
gen
Contains auto generated files.
R.java : generated class which contains references to certain
resources of the project.
res
Android supports resources like images and certain XML
configuration files. This res folder will be having sub-folders
to keep the resources based on its type.
/res/values
Used to define strings, colors, dimensions, styles and static
arrays of strings or integers. By convention each type is
stored in a separate file, e.g. strings are defined in the
res/values/strings.xml file.
/res/values-v11 is the values of the API version 11.
/res/values-v14 is the values of the API version 14
/res/layout
This folder contains the layouts to be used in the application.
A layout resource defines the architecture for the UI in an
Activity or a component of a UI.
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/res/menu
This folder contains menu resources to be used in the application (Options Menu,
Context Menu, or submenu)
/res/drawable
Drawable folders are resource directories in an application that provides different
bitmap drawables for medium, high, and extra high density screens.
/res/drawable-mdpi - bitmap for medium density
/res/drawable-hdpi - bitmap for high density
/res/drawable-xhdpi - bitmap for extra high density
/res/drawable-nodpi - bitmap with no pre-scaling
libs
External library files will be placed in this folder.
assets
This folder contains unstructured raw hierarchy of files and directories, with no other
capabilities.
bin
This Folder is the area used by the compiler to prepare the files to be finally packaged
to the application’s APK file. This includes
- Compiling your Java code into class files
- Putting your resources (including images) into a structure to be zipped into the
APK
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Anatomy of Android Applications
An Android application consists of one or more core components:
1. Activity
2. Service
3. Broadcast receiver
4. Content provider
Activity
• A typical Android application consists of one or more activities.
• Activity is a single screen with a user interface
• An activity usually shows a single visual user interface (UI).
• Only one activity is chosen to be executed first when the application is launched.
• An activity may transfer control and data to another activity through an interprocess
communication protocol called intents.
An activity should have a java class that extends the activity class and an .XML file
to define the interface.
AndroidManifest.xml
This file contains essential information about the application to the Android system,
information the system must have before it can run any of the application's code.
(control general application configuration)
ic_launcher-web.png
This is an icon to be used in Google play. Applications on Google Play require a high
fidelity version of the application icon.
project.properties
Is the main project’s properties file containing information such as the build
platform target. It holds various settings for the build system, updated by the ADT.
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Activity
setContentView(R.layout.activity_first) used to connect the activity code
(FirstActivity)to its XML interface (activity_first)
Graphical Layout
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AndroidManifest.xml
The <intent-filter> declares that this activity is the entry point
(android.intent.action.MAIN) of the application. This activity is to be added to the
application launcher (android.intent.category.LAUNCHER).
Add activity to AndroidManifest.xml
Every time you create new activity, you must add it to the manifest file
Application tab >> Add >> Activity >> Ok*** Browse >> “name of your activity” >> ok
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Lab Work
Create new activity (new class), create new Android xml layout file
and bind them together.
Add a toast to the new activity by the following line:
Toast.makeText(getApplicationContext(), "welcome at the second activity", Toast.LENGTH_SHORT).show();
[Toast will be like this]
Add new activity to the AndroidManifest.xml file.
Bind two activities (default, new) using the following method:
startActivity(new Intent(currentActivity.this,secondActivity.class));
[This method switch between two activities]
Intent details and uses will be shown later ……….
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If you want to create new activity you can
1. Choose class >> then you must add it to the manifest and bind the code with
layout
2. Choose other >> android activity: all configurations will be done.
According to project structure …. Resources folder and its subfolders …..
SEE YOU AT THE NEXT LAB
Homework
Change “Hello World” text into “This is lab 1” and change its
background color into red.
(With/without using code)
Change your application icon.
Change foreground text language to Arabic.
(For example, Hello World will be مرحبا أيها العالم(
(In order to change language: Settings >> Language & Input >>
language >> العربية
Report must include lab work + homework.