Android Workshop

Android Workshop
Getting started with Android application development

About Myself

View slides @ http://www.slideshare.net/samwize

My Hobby Projects

just2us.com

My Hobby Projects

Top App

just2us.com

My Full Time

developer.hoiio.com


Hoiio API


Hoiio API

Mr Brown Podcast Over The Phone!!

Call 6602 8104


Android Apps: txeet


Android Apps: txeet

~250,000
downloads

Android Apps: SG 4D


Android Apps: Hoiio Phone


Android Apps: Hoiio Chat


Contact Me

• twitter @ samwize
• Google+


Schedule

1. Introduction to Android
2. Hands On 1 [45 min]
3. Application Fundamentals & User Interfaces
4. Hands On II [45 min]
5. Advanced Topics - Preferences, Database, Network, Multimedia
6. What’s next?


The Android OS

• Linux Kernel
• Write in Java code
• Dalvik Virtual Machine
• Application Framework
• Ten billion apps downloaded!

A couple of steps

• Install SDK
• Setup Emulator
• Run Emulator
• Create Project
• Run Project

Install SDKs

1. Install Eclipse - the IDE
http://www.eclipse.org/downloads/packages/eclipse-classic-371/indigosr1

2. Install Android SDK
http://developer.android.com/sdk/index.html

3. Install Android ADT Plugin for Eclipse
http://developer.android.com/sdk/eclipse-adt.html#installing

Guide from http://developer.android.com/sdk/installing.html

Setup Emulator

• Add an AVD (Android Virtual Device)
• Go to Windows > AVD Manager > Virtual
devices > New
• Select Google APIs - API Level 10
as target (which is v2.3.3)

Run Emulator

• In AVD Manager, select the newly created
AVD > Start

Create Project

• File > New > Android Project
• Fill in:
• Project name
• Build target
• Application name
• Package name
• Activity
• Min SDK Version

Run Project

• Run > Run as > Android Application

Run on Actual Device

• To run on actual Android device, connect
device to computer via USB
• From device, go to Settings > Applications
> Development > enabled USB debugging
• Run project

3. Application Fundamentals &
User Interface

Now that you see “Hello World”, let’s examine the project..

Project Structure

R.drawable.icon
R.layout.main
R.string.hello

Fundamentals

• 4 main components:
1. Activity
2. Service
3. ContentProvider
4. BroadcastReceiver

Activity

• Activity = Screen
• An app is made up of multiple activities
• Stack of activities/screens
• Activity lifecycle

HelloWorldActivity

Activity class has functions to handle onCreate, onResume, onPause, etc

Activity

• Launch an Activity by calling
startActivity(intent)

Launch a known Activity
Intent intent = new Intent(this, SignInActivity.class);
startActivity(intent);

Activity

• Launch an Activity by calling
startActivity(intent)

Launch a known Activity
Intent intent = new Intent(this, SignInActivity.class);

Launch a system Activity
Intent intent = new Intent(Intent.ACTION_SEND);
intent.putExtra(Intent.EXTRA_EMAIL, recipientArray);

Activity

• Activity must be declared in AndroidManifest.xml

<manifest ... >
<application ... >
<activity android:name=".HelloWorldActivity" />
...
</application ... >
...
</manifest >

Service

• Service runs in the background, even when user is not
interacting with your app

• Service or Thread ?

• To start, call startService()

• Similar to Activity, has its lifecycle and various event
callbacks

ContentProvider

• A way to share data across applications,
including apps such as phonebook,
calendar, etc.
• In other words, you can access the
phonebook using a ContentProvider
• Have query, insert, delete methods (SQLite)
ContentResolver cr = getContentResolver();
cr.query(“content://android.provider.Contacts.Phones.CONTACT_URI”,
projection,
selection, selectionArg,
sortOrder)

BroadcastReceiver

• Responds to system-wide broadcast
announcements such as incoming phone
call, SMS sent, picture captured, etc

User Interfaces

Slides on http://www.slideshare.net/samwize

View Hierarchy

1. View - Android UI component, view or widget
2. ViewGroup - Layout or container view

View

• UI components can be found in
android.widget package
• Basic UI:

• TextView

• Button

• TextField

• Progress bar

• List

• etc..

User Interfaces

• 2 ways to construct UI
1. XML
2. Code

The way of XML
/res/layout/main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:layout_height="wrap_content"
android:text="@string/hello"
/>
</LinearLayout>

The way of XML
>
<TextView
/>
</LinearLayout>

looks in /res/values/string.xml, and
ﬁnd the value for the key “hello”

The way of XML
>
<TextView
/>
</LinearLayout>

Equivalently..
android:text="Hello world too!"

The way of XML
>
<TextView
/>
</LinearLayout>

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}

The way of XML
>
<TextView
/>
</LinearLayout>

@Override
}

setContentView() inﬂate main.xml and set the views

The way of Code

package com.just2us.helloandroid;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class HelloAndroid extends Activity {
/** Called when the activity is first created. */
@Override
TextView textview = new TextView(this);
textview.setText("Hello, Android");
setContentView(textview);
}
}

The way of Code



@Override
}
}

Creating a TextView and set the text

The way of Code



@Override
}
}

Similarly to the way of XML, setContentView()

1) Linear Layout

• Follow tutorial from:
http://developer.android.com/resources/
tutorials/views/hello-linearlayout.html

2) Form Stuff

• Follow tutorial from:
http://developer.android.com/resources/
tutorials/views/hello-formstuff.html

More tutorial..

• “Hello View” tutorials
• http://developer.android.com/resources/tutorials/views/index.html

• “Api Demo” sample code
• http://developer.android.com/resources/samples/ApiDemos/
index.html

5. Advanced Topics
Preferences, Database, Network, Multimedia

Preferences

• The easiest way to store information
• NOT only store preferences/settings, but
also arbitrary key-value pairs
• SharedPreference class
• getBoolean, setBoolean, etc..

Preferences
public class Calc extends Activity {
public static final String PREFS_NAME = "MyPrefsFile";

@Override
protected void onCreate(Bundle state){
super.onCreate(state);

// Restore preferences
SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
boolean silent = settings.getBoolean("silentMode", false);
setSilent(silent);
}

@Override
protected void onStop(){
super.onStop();

// We need an Editor object to make preference changes.
// All objects are from android.context.Context
SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
SharedPreferences.Editor editor = settings.edit();
editor.putBoolean("silentMode", mSilentMode);

// Commit the edits!
editor.commit();
}
}

Database

• Tabular data
• SQLite behind the scenes
• Extend SQLiteOpenHelper

Database

public class DictionaryOpenHelper extends SQLiteOpenHelper {

private static final int DATABASE_VERSION = 2;
private static final String DICTIONARY_TABLE_NAME = "dictionary";
private static final String DICTIONARY_TABLE_CREATE =
"CREATE TABLE " + DICTIONARY_TABLE_NAME + " (" +
KEY_WORD + " TEXT, " +
KEY_DEFINITION + " TEXT);";

DictionaryOpenHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}

@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(DICTIONARY_TABLE_CREATE);
}
}

Database

• Call getWritableDatabase() or
getReadableDatabase() to get an
SQLiteDatabase object
• With SQLiteDatabase, call query() to
execute SQL queries

Network

• Connect to web services over HTTP
• Permission needed in Manifest
<uses-permission android:name="android.permission.INTERNET" />

• A few different ways to connect
• HttpClient is most robust

Network - GET

HttpClient client = new DefaultHttpClient();
HttpGet request = new HttpGet("http://www.myserver.com/script1.php");

// Execute HTTP GET request and get response
HttpResponse response = client.execute(request);
InputStream is = response.getEntity().getContent();
BufferedReader in = new BufferedReader(new InputStreamReader(is));
// Do what you need with content StringBuffer sb = new StringBuffer("");
String line = "";
String NL = System.getProperty("line.separator");
while ((line = in.readLine()) != null) {
sb.append(line + NL);
}
in.close();
String content = sb.toString();

// Do what you need with content
...

Network - POST

HttpClient client = new DefaultHttpClient();
HttpPost request = new HttpPost("http://www.myserver.com/login_script.php");

// Add your data
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("username", "samwize"));
nameValuePairs.add(new BasicNameValuePair("password", "123456"));
request.setEntity(new UrlEncodedFormEntity(nameValuePairs));

// Execute HTTP POST Request
HttpResponse response = httpclient.execute(request);

Multimedia

• Camera
• Playback audio and video

Multimedia - Camera

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

Multimedia - Camera

• 2 ways to capture photo
• Using capture intent
• Using Camera class directly

Multimedia - Camera

private static final int CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE = 100;
private Uri fileUri;

@Override

// create Intent to take a picture and return control to the calling application
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);

fileUri = getOutputMediaFileUri(MEDIA_TYPE_IMAGE); // create a file to save the image
intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri); // set the image file name

// start the image capture Intent
startActivityForResult(intent, CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE);
}

Capture photo

Multimedia - Camera

private static final int CAPTURE_VIDEO_ACTIVITY_REQUEST_CODE = 200;

@Override

//create new Intent
Intent intent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);

fileUri = getOutputMediaFileUri(MEDIA_TYPE_VIDEO); // create a file to save the video

intent.putExtra(MediaStore.EXTRA_VIDEO_QUALITY, 1); // set the video image quality to high

// start the Video Capture Intent
startActivityForResult(intent, CAPTURE_VIDEO_ACTIVITY_REQUEST_CODE);
}

Multimedia - Camera


@Override

//create new Intent
Intent intent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);

fileUri = getOutputMediaFileUri(MEDIA_TYPE_VIDEO); // create a file to save the video

intent.putExtra(MediaStore.EXTRA_VIDEO_QUALITY, 1); // set the video image quality to high

// start the Video Capture Intent
startActivityForResult(intent, CAPTURE_VIDEO_ACTIVITY_REQUEST_CODE);
}

Capture video

Multimedia - Camera

private static final int CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE = 100;

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE) {
if (resultCode == RESULT_OK) {
// Image captured and saved to fileUri specified in the Intent
Toast.makeText(this, "Image saved to:n" +
data.getData(), Toast.LENGTH_LONG).show();
} else if (resultCode == RESULT_CANCELED) {
// User cancelled the image capture
} else {
// Image capture failed, advise user
}
}

if (requestCode == CAPTURE_VIDEO_ACTIVITY_REQUEST_CODE) {
if (resultCode == RESULT_OK) {
// Video captured and saved to fileUri specified in the Intent
Toast.makeText(this, "Video saved to:n" +
data.getData(), Toast.LENGTH_LONG).show();
} else if (resultCode == RESULT_CANCELED) {
// User cancelled the video capture
} else {
// Video capture failed, advise user
}
}
}

Handling after photo/video is captured by camera app

Multimedia - MediaPlayer

• Play audio and video from:
• /res/raw/
• File system (internal or external)
• Stream over Internet
• MediaPlayer class


<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WAKE_LOCK" />


MediaPlayer mediaPlayer = MediaPlayer.create(context, R.raw.sound_file_1);
mediaPlayer.start();
...
mediaPlayer.stop();

Playing /res/raw/sound_ﬁle_1.mp3


String url = "http://........"; // your streaming URL here
MediaPlayer mediaPlayer = new MediaPlayer();
mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
mediaPlayer.setDataSource(url);
mediaPlayer.prepare(); // might take long! (for buffering, etc)
mediaPlayer.start();

Playing audio stream from Internet


• Playing video is similar to audio
• Pass a SurfaceHolder (view class) which the
MediaPlayer can render the video on

More Topics

• Location (GPS) and Map
• Bluetooth
• USB host and accessory
• Animation
• OpenGL ES

Notepad Tutorial

• Exercise 1- ListActivity and database
http://developer.android.com/resources/tutorials/notepad/notepad-ex1.html

• Exercise 2 - Invoke another activity
• Exercise 3 - application life cycle

Sample Code

• Sample Codes
http://developer.android.com/resources/samples/get.html

• API Demo, Bluetooth Chat, News Reader,
Accelerometer Play, Contact Manager, etc

User Interfaces

• Supporting different screen sizes
http://developer.android.com/guide/practices/screens_support.html

• Common UI Patterns
http://www.androidpatterns.com/

Important Resources

• http://developer.android.com
• http://stackoverﬂow.com/
• http://www.google.com/

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