Introduction to Android Develpment

Me and my friend Eugeniu Arbuleac had the pleasure to present an Introduction to Android development course at Google Developers Group Bucharest first 2013 meetup.

Transcript

1. Introduction to Android Development
2. Eugeniu Arbuleac @arbuleac arbuleac.ev@gmail.com Andrei Catinean @electryc andrei.catinean@gmail.com WHO WE ARE
3. Activities and UI Intents Services Broadcast Receivers
4. Activities and UI
5. Activities and UI A screen Application = Σ activity
6. Activity Lifecycle
7. Managed by ActivityManager Activity Lifecycle
8. Developer says what happens at each state $ ¢ Activity Lifecycle Managed by ActivityManager
9. D/MyActivity( 1146): onCreate D/MyActivity( 1146): onStart D/MyActivity( 1146): onResume First time run D/MyActivity( 1146): onClickAnotherActivity D/MyActivity( 1146): onPause D/MyActivity( 1146): onStop D/MyActivity( 1146): onRestart D/MyActivity( 1146): onStart D/MyActivity( 1146): onResume Open another activity, then Back button Activity Lifecycle
10. D/MyActivity( 1146): onPause D/MyActivity( 1146): onStop D/MyActivity( 1146): onDestroy D/MyActivity( 1146): onCreate D/MyActivity( 1146): onStart D/MyActivity( 1146): onResume Rotate screen Activity Lifecycle
11. D/MyActivity( 1146): onPause D/MyActivity( 1146): onStop Home Button D/MyActivity( 1146): onPause D/MyActivity( 1146): onStop D/MyActivity( 1146): onDestroy D/MyActivity( 1146): onCreate D/MyActivity( 1146): onStart D/MyActivity( 1146): onResume Rotate screen Activity Lifecycle
12. package ro.gdgcluj.demoapp; import android.app.Activity; import android.os.Bundle; import android.util.Log; public class MyActivity extends Activity { static final String TAG = MyActivity.class.getSimpleName(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_my); Log.d(TAG, "onCreate"); } @Override protected void onStart() { super.onStart(); Log.d(TAG, "onStart"); } @Override protected void onResume() { super.onResume(); Log.d(TAG, "onResume"); } Activity Lifecycle
13. @Override protected void onPause() { super.onPause(); Log.d(TAG, "onPause"); } @Override protected void onRestart() { super.onRestart(); Log.d(TAG, "onRestart"); } @Override protected void onStop() { super.onStop(); Log.d(TAG, "onStop"); } @Override protected void onDestroy() { super.onDestroy(); Log.d(TAG, "onDestroy"); } }
14. Declaring the Activity <manifest ... > <application ... > <activity android:name=".MyActivity" /> ... </application ... > ... </manifest > Let your application know about your Activity into the AndroidManifest.xml
15. For your main activity use Intent Filters <manifest ... > <application ... > <activity android:name=".MyActivity" > <intent-filter> <action android:name= "android.intent.action.MAIN" /> <category android:name= "android.intent.category.LAUNCHER" /> <intent-filter /> <activity /> </application ... > ... </manifest > <manifest ... > <application ... > <activity android:name=".MyActivity" /> ... </application ... > ... </manifest > Let your application know about your Activity into the AndroidManifest.xml Declaring the Activity
16. Building Android UI XML Declare UI in XML Inflate XML in Java files
17. Building Android UI Programmatically Initialize new widgets Customize properties for each VS. XML Declare UI in XML Inflate XML in Java files
18. Use them both Programmatically Initialize new widgets Customize properties for each VS. XML Declare UI in XML Inflate XML in Java files Building Android UI
19. Layouts and views hierarchy
20. Intents
21. Used to start activities, start/stop services, or send broadcasts Intents
22. startActivity(Intent activity); startService(Intent service); stopService(Intent service); sendBroadcast(Intent intent); Using Intents
23. startActivity(new Intent(this, TargetActivity.class)); startService(new Intent(this, TargetService.class)); Explicit Intents
24. startService(new Intent("example.intent.action.IntentService")); sendBroadcast(new Intent("example.intent.action.Receiver")); Implicit Intents startActivity(new Intent(this, TargetActivity.class)); startService(new Intent(this, TargetService.class)); Explicit Intents
25. <service android:name=".IntentService"> <intent-filter> <action android:name="example.intent.action.IntentService" /> </intent-filter> </service> <receiver android:name=".Receiver"> <intent-filter> <action android:name="example.intent.action.Receiver" /> </intent-filter> </receiver> startService(new Intent("example.intent.action.IntentService")); sendBroadcast(new Intent("example.intent.action.Receiver")); Implicit Intents startActivity(new Intent(this, TargetActivity.class)); startService(new Intent(this, TargetService.class)); Explicit Intents AndroidManifest.xml
26. Intent Filters Activity Service Receiver Action
27. <intent-filter> <action android:name="any.action.you.want" /> </intent-filter> Intent Filters Action Activity Service Receiver AndroidManifeset.xml
28. Services
29. Run in background Don’t have UI Run on the UI thread Services
30. UI Activity Service startService(); stopService(); Services Run in background Don’t have UI Run on the UI thread
31. Service starts and "runs" until it gets a request to stop To offload work from main thread, use intent service. Intent service uses worker thread, stops when done with work. Service Lifecycle
32. package ro.gdgcluj.demoapp; import android.app.Service; import android.content.Intent; import android.os.IBinder; import android.util.Log; public class MyService extends Service { static final String TAG = MyService.class.getSimpleName(); @Override public IBinder onBind(Intent arg0) { return null; } @Override public void onCreate() { Log.d(TAG, "onCreate"); } @Override public int onStartCommand(Intent intent, int flags, int startId) { Log.d(TAG, "onStartCommand"); return START_STICKY; } @Override public void onDestroy() { Log.d(TAG, "onDestroy"); } } Service Example
33. <service android:name=".ServiceDemo"></service> Called via its class name <service android:name=".IntentService"> <intent-filter> <action android:name="example.intent.action.IntentService" /> </intent-filter> </service> Declaring the Service Called via action
34. Broadcast Receivers
35. Intent based publish-subscribe mechanism Listening system events: incoming calls, SMS messages a.o. Broadcast Receivers
36. Register for certain intents Get notified when intent happens Intent based publish-subscribe mechanism Listening system events: incoming calls, SMS messages a.o. Broadcast Receivers
37. package ro.gdgcluj.demoapp; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.util.Log; public class Receiver extends BroadcastReceiver { static final String TAG = Receiver.class.getSimpleName(); @Override public void onReceive(Context context, Intent intent) { Log.d(TAG, "onReceive action: "+intent.getAction() ); } } Broadcast Receiver Example
38. <receiver android:name=".ReceiverDemo"> <intent-filter> <action android:name="example.intent.action.Receiver" /> </intent-filter> </receiver> Declaring it in AndroidManifest.xml Registering the Broadcast Receiver
39. @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); ... // Create the receiver receiver = new Receiver(); filter = new IntentFilter( ANY_INTENT_ACTION ); } protected void onResume() { super.onResume(); super.registerReceiver(receiver, filter); } @Override protected void onPause() { super.onPause(); unregisterReceiver(receiver); } Registering the Broadcast Receiver Registering Programmatically
40. Questions That’s all!
41. Eugeniu Arbuleac @arbuleac arbuleac.ev@gmail.com Andrei Catinean @electryc andrei.catinean@gmail.com THANK YOU