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Android development basics
Introduction,Structure,Development
Boncho Valkov
.Net Developer
Table of Contents
1. About Android and why to use it
2. What knowledge do you need to start
 Basics of programming,OOP,Databases
3. What software (IDEs) do you need
 Android Studio/Eclipse
 Emulator – Genymotion or other
4. Structure of Android app
5. Main components – Intent,Activity,Service,Content
Provider,Broadcast Receiver
6. Activities lifecycle
2
Table of Contents
7. Debugging and logging
8. Intents, passing data between activities
9. Views. Layout Management
10.Listviews and Adapters
11.Notifications
12.HTTP Networking. AsyncTasks and Callbacks
13.Local Storage – SQLLite and SharedPrefs. Content Provider.
3
About Android and why to use it
4
About Android
 Android is a mobile operating system (OS) based on the Linux
kernel and currently developed by Google.
 Started back in 2008, today is the most popular mobile OS with
1.5 million daily activations, 1 billion devices in total (as of
April 2013).
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About Android - Architecture
6
Why android
 The most popular mobile OS
 Large community
 Extremely well documented APIs
 Reuse existing knowledge in
 Java development
 Uses MVC
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What do you have to know to start
 Basics of programming in some object
oriented language like C#, Java or other
 OOP principals
 Databases – SQL/MYSQL or other
 XML
8
What software (IDEs) do you need
1. For programming

Android studio – for a couple of months there is
official version

Eclipse plus SDK tools
2. Emulator

Genymotion

Integrated emulator in android studio

Test on actual device
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Structure of Android project
 Select API Level
 Using Packages like JAVA
 Java folder
 Res folder
 Android Manifest file
 Gradle
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Main components
 Activity
 Intent
 Service
 Content Provider
 --------------------
 Broadcast Receivers
 Fragments
 Views
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Activity
 Represents a single screen with an user
interface plus code that runs behind it
 If we have multiple activities – one must be
selected as the app’s main activity.
 The main activity is similar to the main()
function in Java and C#
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Intent
 Objects carrying messages from one
component to another (within the
application or outside it).
 Two types of intents:
•
Explicit intents – tell exactly what do
you want to start to get some result
•
Implicit intents – tell that you what
some result, without specifying how
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Service
 Runs in the background to perform long- running operations.
 Doesn’t need to interact with the user.
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Content Providers
 Supplies data from one application to
others on request.
 - Can use different ways to store data
(database, files, over a network).
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Broadcast Receivers
 Respond to broadcast messages from other applications or from
the system itself (called events or intents).
 Applications can also initiate broadcasts to let other
applications know that some data has been downloaded or
processed.
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Fragments
 Kind of sub-activity
 Can be placed in an Activity to achieve more modular design.
 -You can add or remove fragments in an activity while the
activity is running.
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Views
 Layouts
 Widgets

Menu

Drawer

Tabs
 Can be created via:

-XML files

Programmatically
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Activity Lifecycle
Activity Lifecycle
 onCreate
 onStart
 onResume – application is running
 onPause
 onStop
 onDestroy
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Demo
Debugging and logging
Debugging and logging
 F8 – step forward
 F9 – go next breakpoint
 Log.v() -VERBOSE
 Log.d() -DEBUG
 Log.i() -INFO
 Log.w() -WARN
 Log.e() -ERROR
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Demo
Intents, passing data between
activities
Intents
 What is an intent
 messages you can pass between your app components
 can also send them to components in other apps,
and execute a task
like playing music,
sending email
and taking pictures.
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Intents
 With an Intent you can
 Start activities
 Start services
 Deliver broadcasts

Pass data
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Intents
 Types of intents
 Implicit

have not specified a component

they must include enough information for the system to determine
which of the available components is best to run for that intent.
Intent intent = new Intent (Intent.ACTION_VIEW, Uri.parse("http://www.softuni.bg "));
startActivity(intent);
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Intents
 Implicit
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Intents
 Types of intents
 Explicit

have specified a component, which provides the exact class to be
run

usually is used for starting internal activities
Intent intent = new Intent (this,SecondActivity.class);
startActivity(intent);
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Passing data between activities
 Put the data in the intent
Intent intent = new Intent (this,SecondActivity.class);
intent.putExtra("data","i have been passed");
startActivity(intent);
 Retrieve the data from the intent from the component that has
been started, usually in onCreate method
Intent intent = getIntent();
String passedData = intent.getExtra(“data”);
 Serializable objects can be passed
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Intent Filters
 We use the intent filters to deny or allow intents to reach our
app’s components.
<action android:name="android.intent.action.SEND"/>
<data
android:mimeType="text/plain"/>
<category android:name="android.intent.category.DEFAULT"/>
 Restrict access
<activity android:exported = false>
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Demo
Views. Layout Management
Views. Layout Management
 Mandatory view props
 android:layout_width
 android:layout_height
 Match parent
 Fill parent
 Wrap Content
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Linear Layout
 Single direction, vertically or horizontally
 Specified by the android:orientation attribute
 All children are stacked one after another
 Can use gravity
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Relative Layout
 Displays child views in relative positions
 The position of each view can be specified as relative to sibling
elements
 Can align two elements by right border
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Demo
List Views and Adapters
List Views and Adapters
 Parts of the ListView:

Rows

Adapter -bridge between a
view and the underlying data
for that view. Provides access
to the data items.

Fast Scrolling

Section Index
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List Views and Adapters
 Types of list views and adapters
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Simple List View
<ListView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/listView"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true" />
 Create ArrayAdapter
 Set Adapter to the listView
 Set OnClickListener
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Custom List View Adapter
 Most of the time we need something
specific
 Create custom row
 Create Custom Adapter that extents
BaseAdapter
 Implement required methods
convertView = LayoutInflater.from(context)
.inflate(R.layout.university_row,parent,false);
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Demo
Notifications
Notifications Components
 Three required components
 Icon
 Content title
 Content text
 Optional components
 Action attached to notification, usually an Activity, it’s done by
Pending Intent, by calling set Content Intent
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Notification sample
NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(this)
.setSmallIcon(R.drawable.notification_icon)
.setContentTitle("My notification")
.setContentText("Hello World!");
 If want to add action to Notification
 Create Intent
 Create PendingIntent, by PendingIntent.getActivity
 Use setContentIntent to attach the pending Intent
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Demo
Along with the live demo
HTTP Networking. AsyncTasks
and Callbacks
Http
 Hypertext Transfer Protocol
(HTTP)
 HTTP is the foundation of data
communication for the World
Wide Web.
 Needs permmitions
HttpClient defaultHttpClient = new DefaultHttpClient(new
BasicHttpParams());
HttpPost httpPost = new HttpPost(path);
HttpResponse response = defaultHttpClient.execute(httpPost);
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AsyncTask
 Class that that is being executed on a different thread
 Prevent using the Main thread (UI) for time taking operations
 Extend class with AsyncTask<String,Void,String>
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Demo
Local Storage – SQLLite and
SharedPrefs. Content Provider.
Content Providers
 Manage access to a structured set of data
 Encapsulate the data, and provide mechanisms for defining data
security
 The standard interface that connects data in one process with
code running in another process.
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SQLite
 Software library that implements a self-contained, zeroconfiguration, transactional SQL database engine.
 The most widely deployed SQL database engine in the world.
 Useful tools and queries:
 - DB Browser for SQLite
 Create, Select,
Delete, Update
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Local storage
 Shared Preferences Store private primitive data in key-value
pairs.
SharedPreferences sp = getSharedPreferences(PREFS,
Context.MODE_PRIVATE);
Editor editor = sp.edit();
editor.putString("key", "value");
editor.commit();
if (sp.contains(Name))
name.setText(sp.getString(Name, ""));
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Demo
Questions? 