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
   

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2. Eugeniu Arbuleac
   @arbuleac
   arbuleac.ev@gmail.com
   Andrei Catinean
   @electryc
   andrei.catinean@gmail.com
   WHO WE ARE
   

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3. Activities and UI
   Intents
   Services
   Broadcast Receivers
   

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4. Activities and UI
   

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5. Activities and UI
   A screen
   Application = Σ activity
   

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6. Activity Lifecycle
   

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7. Managed by ActivityManager
   Activity Lifecycle
   

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8. Developer says what happens at each state
   $
   ¢
   Activity Lifecycle
   Managed by ActivityManager
   

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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
   

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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
    

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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
    

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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
    

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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");
    }
    }
    

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14. Declaring the Activity
    
    
    
    ...
    
    ...
    
    Let your application know about your Activity into the AndroidManifest.xml
    

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15. For your main activity use Intent Filters
    
    
    
    
    
    
    
    
    
    ...
    
    
    
    
    ...
    
    ...
    
    Let your application know about your Activity into the AndroidManifest.xml
    Declaring the Activity
    

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16. Building Android UI
    XML
    Declare UI in XML
    Inflate XML in Java files
    

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17. Building Android UI
    Programmatically
    Initialize new widgets
    Customize properties for each
    VS.
    XML
    Declare UI in XML
    Inflate XML in Java files
    

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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
    

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19. Layouts and views hierarchy
    

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20. Intents
    

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21. Used to start activities, start/stop services, or send broadcasts
    Intents
    

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22. startActivity(Intent activity);
    startService(Intent service);
    stopService(Intent service);
    sendBroadcast(Intent intent);
    Using Intents
    

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23. startActivity(new Intent(this, TargetActivity.class));
    startService(new Intent(this, TargetService.class));
    Explicit Intents
    

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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
    

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25. 
    
    
    
    
    
    
    
    
    
    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
    

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26. Intent Filters
    Activity
    Service
    Receiver
    Action
    

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27. 
    
    
    Intent Filters
    Action
    Activity
    Service
    Receiver
    AndroidManifeset.xml
    

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28. Services
    

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29. Run in background
    Don’t have UI
    Run on the UI thread
    Services
    

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30. UI Activity
    Service
    startService(); stopService();
    Services
    Run in background
    Don’t have UI
    Run on the UI thread
    

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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
    

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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
    

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33. 
    Called via its class name
    
    
    
    
    
    Declaring the Service
    Called via action
    

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34. Broadcast Receivers
    

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35. Intent based publish-subscribe mechanism
    Listening system events: incoming calls, SMS messages a.o.
    Broadcast Receivers
    

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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
    

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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
    

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38. 
    
    
    
    
    Declaring it in AndroidManifest.xml
    Registering the Broadcast Receiver
    

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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
    

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40. Questions
    That’s all!
    

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41. Eugeniu Arbuleac
    @arbuleac
    arbuleac.ev@gmail.com
    Andrei Catinean
    @electryc
    andrei.catinean@gmail.com
    THANK YOU
    

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