The document discusses starting another activity in Android mobile software engineering. It explains that an intent carries data through key-value pairs called extras between components like activities. Keys for extras should be prefixed with the app's package name to ensure uniqueness. The document provides an example of starting a new activity by creating an intent, adding an extra string message, and calling startActivity. It also covers the activity lifecycle methods like onPause(), onResume(), and onSaveInstanceState(). The rest of the document lists additional advanced Android training topics.

1. Mobile
Software
Engineering
L04 – Android Cont.
Mohammad Shaker
FIT of Damascus - AI dept.
MohammadShakerGtr@gmail.com
Mobile SE – August 2012

2. Activities
Starting Another Activity

3. Intent
an object that provides runtime binding between separate
components (such as two activities)

4. Intent
carry a collection of various data types as key-value pairs
called extras through putExtra()

5. It’s a good practice..
to define keys for intent extras using your app's package name as a prefix.
This ensures they are unique, in case your app interacts with other apps.

6. Starting Another Activity
http://developer.android.com/training/basics/firstapp/starting-activity.html#BuildIntent
Project Attached

7. Starting Another Activity
public final static String EXTRA_MESSAGE =
"com.example.intetsample.MESSAGE";
public void sendMessage(View view) {
Intent intent = new Intent(this, DisplayMessageActivity.class);
EditText editText = (EditText) findViewById(R.id.editText1);
String message = editText.getText().toString();
intent.putExtra(EXTRA_MESSAGE, message);
startActivity(intent);
}

8. AndroidManifest.xml

9. AndroidManifest.xml
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/title_activity_main" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".DisplayMessageActivity"
android:label="@string/title_activity_display_message" >
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="com.example.intetsample.MainActivity" />
</activity>
</application>

10. Managing the Activity
Life Cycle

12. Destroy the activity
onDestroy()

13. Destroy the activity

14. onPasue()
@Override
public void onPause() {
// Always call the superclass method first
super.onPause();
// Release the Camera because
// we don't need it when paused
// and other activities might need to use it.
if (mCamera != null) {
mCamera.release()
mCamera = null;
}
}

15. onResume()
@Override
public void onResume() {
// Always call the superclass method first
super.onResume();
// Get the Camera instance as the activity
// achieves full user focus
if (mCamera == null) {
// Local method to handle camera init
initializeCamera(); }
}

16. Recreating activity
onSaveInstanceState

17. Storage – Database
Sqlite3

18. Draggable stick
project sample attached

19. OpenGL ES

20. How can we animate?

21. 'Must Override a Superclass
Method' Errors after importing a
project into Eclipse Problem
http://stackoverflow.com/questions/1678122/must-override-a-superclass-
method-errors-after-importing-a-project-into-eclips

22. @Override
public boolean onTouchEvent(MotionEvent e) {
float x = e.getX(); float y = e.getY();
switch (e.getAction()) {
case MotionEvent.ACTION_MOVE:
float dx = x - mPreviousX; float dy = y - mPreviousY;
// reverse direction of rotation above the mid-line
if (y > getHeight() / 2) { dx = dx * -1 ; }
// reverse direction of rotation to left of the mid-line
if (x < getWidth() / 2) { dy = dy * -1 ; }
mRenderer.mAngle += (dx + dy) * TOUCH_SCALE_FACTOR;
// = 180.0f / 320
requestRender();
}
mPreviousX = x; mPreviousY = y;
return true;
}

23. Let’s get our hands dirty
with code!

24. Advanced Training
• Making Your App Location Aware
• Performing Network Operations
• Transferring Data Without Draining the Battery
• Syncing to the Cloud
• Designing for Multiple Screens
• Improving Layout Performance
• Managing Audio Playback
• Optimizing Battery Life
• Creating Custom Views
• Adding Search Functionality
• Remembering Users
• Sharing Content
• Capturing Photos
• Maintaining Multiple APKs
• Creating Backward-Compatible UIs
• Developing for Enterprise
• Monetizing Your App
• Designing Effective Navigation
• Implementing Effective Navigation
• Designing for TV
• Displaying Bitmaps Efficiently
• Implementing Accessibility
• Displaying Graphics with OpenGL ES

25. See you nxt time!