1. HUJI Post PC Workshop 1 Introduction to Android Development Ari Sprung

2. Workshops Structure Workshop 1 – Introduction
Setting up, basic app, views, layouts
Workshop 2 – Adapters and Menus
Resources, adapter views, menus, unit testing
Workshop 3 – Activities
Multiple activities, dialogs, intents
Workshop 4 – Persistence
SQLite, cursors, backend-as-a-service
Workshop 5 – Threading
Files, threads, web services

3. Prerequisites and Homework
What you need to know:
Java programming, collections, files, etc.
Database basics, tables, SQL
Homework will involve:
Application development
Activity testing
Using source control

4. Make Sure You’re OK With This:
Thread t = new Thread(new Runnable() {
public void run() {
Connection c = DriverManager.getConnection(...);
Statement s = c.createStatement();
ResultSet r = s.executeQuery( “SELECT name, AVERAGE(grade) avg “ “FROM students GROUP BY grade “ “ORDER BY avg DESC”);
while (r.next()) { ... } }
});
t.start();

5. Before We Begin…
You can’t learn from the slides. The slides are a learning aid, and they will not contain all the information discussed in class. You still have to come to class and use additional reading to fill the gaps.

6. Android Architecture

7. Versions and API Levels
Considerable fragmentation
API levels correspond to each version

8. Setting Up Dev Environment
Download the Android Studio for your OS
Contains Eclipse and Android SDK
Use SDK Manager to download multiple versions of Android
Use AVD Manager to create emulator images for various versions(not recommend).
Genny Motion

9. Demonstration: Dev Tools
Studio
SDK Manager
Gradle
Emulator

10. Hello World App Components
src – your package’s sources
gen – code generated by the compiler
Do not touch this
res – resources: images, strings, layouts
res/layout/main.xml – your main UI
AndroidManifest.xml – app description
bin – binary products, including your apk

11. Application Components
Activity
Screen, form – usually full-screen, one at a time
Activity subclass
View
Anything that appears on the screen: button, edit box (EditText), label (TextView)
Layout
A component that manages a bunch of views and decides how to position and draw them

12. Code-Layout Separation
Your view lives in XML files (layouts)
Your code lives in Java files
Your view communicates with your code through listeners
Your code communicates with your view through object references
<Button android:text=“Click me” />
final Button b = (Button) findViewById(R.id.btn1);
b.setOnClickListener(
new OnClickListener() {
public void onClick(View v) {
b.setText(“Thanks!”); }
});

13. Basic Views
Explore the standard Android views and how they are declared in XML
<Button android:text=“Button” />
<EditText android:hint=“phone” />
<CheckBox android:checked=“true” />

14. Basic Layouts
LinearLayout stacks elements horizontally/vertically (orientation)
It’s often very useful to nest layouts
<LinearLayout
android:orientation=“horizontal”>
<ImageView
android:layout_weight=“1”
android:layout_height=“fill_parent”
... />
<TextView
android:layout_weight=“2”
<WebView ... />
</LinearLayout>

15. Basic Layouts
RelativeLayout allows relative positioning of child elements
<RelativeLayout>
<ImageView
android:layout_width=“fill_parent”
... />
<TextView
android:layout_alignParentLeft=“true”
<Button ... />
</RelativeLayout>

16. Demonstration: UI Events
Your activity class’ onCreate method creates the UI from an XML file
Then, retrieve views and use listeners
public class MyActivity extends Activity {
@Override
public void onCreate(Bundle unused) {
super.onCreate(unused);
setContentView(R.layout.main);
EditText ed = (EditText)findViewById(R.id.ed);
ed.setOnTextChangeListener(...);
Button btn = (Button)findViewById(R.id.btn);
btn.setTextSize(14.0f); }

17. Demonstration: Source Control
Source control: management of changes to source code
Logical branching and versioning
Development history, rollback
Change tracking
You will be using GitHub for your homework assignments and final projects
Go to create an account
For each homework, associate your username with the GitHub repository

18. Homework 1 Tip (12%) Calculator Fill submission form
12:38
Tip (12%) Calculator
Package: il.ac.huji.tipcalculator
Repo tag: v1
Activity: TipCalculatorActivity
Fill submission form
Pay attention to view ids:
edtBillAmount
chkRound
btnCalculate
txtTipResult
42.20
Bill Amount
Round to nearest dollar
Calculate
Tip: $5
When rounding to nearest dollar, do not print decimal separator and any trailing digits.
When not rounding to nearest dollar, ALWAYS print decimal separator and two trailing digits, e.g.: $6.00, $6.12

19. Additional Resources Tools workflow App fundamentals Layouts
App fundamentals
Layouts
Handling input events
Stack Overflow