Programming Mobile Applications for Android Handheld systems, Part 1

Course page: https://class.coursera.org/androidpart2-001
By Dr. Adam Porter

Source code available at: https://github.com/aporter/coursera-androidc

• Using HTTP get requests.
• Processing HTTP responses, with JSON and XML.
• Supoprt classes:
  • Socket (java.net)
    • using input/output streams
  • HttpRequest and HttpResponse (in org.apache)
  • Uri, AndroidHttpClient, AudioStream (in android.net)
  • HttpUrlConnection
    • using URL.openConnection()
  • AndroidHttpClient
    • create new instance with AndroidHttpClient.newInstance(“”)
    • create HttpGet(URL)
    • create ResponseHandler<String> (BasicResponseHandler for instance)
    • call client.execute(request, responseHandler);

• JSON format
  • 2 types of structures:
    • maps
    • ordered lists
• XML format
  • DOM (complete reading of the document object model)
  • SAX (stream reading with callbacks) parsers.
  • PULL similar to SAX but the reading of the next element is controlled by the application.

• BroadcastReceiver class
  • Wait for events, receive them and react to them
  • Broadcast receiver register for the type of events they are interested in.
  • Intent are broadcasted
  • onReceive() method called with received intent.
• Registration
  • Static registration:
    • <receiver> tag with <intent-filter> inside.
    • attributes:
      • android:enabled=[true|false]
      • android:exported=[true|false]
      • android:icon
      • android:name
      • android:permission
  • Dynamic registration
    • create IntentFilter object
    • create BroadcastReceiver
    • register BroadcastReceiver using registerReceiver()
      • from LocalBroadcastManager
      • context
    • call unRegisterReceiver()

• Broadcast
  • Normal or ordered.
  • sticky or non-sticky.
  • With or without receiver permission.
  • debug details with: Intent.setFlag(FLAG_DEBUG_LOG_RESOLUTION)
  • adb dumpsys to get more info on broadcast receiver.

• Processing
  • Event delivery:
    • onReceive():
      • context
      • intent
  • BroadcastReceiver are only valid while in onReceive() method.
  • sendOrderedBroadcast()
    • IntentFilter.setPriority()
  • abortBroadcast() ⇒ to stop a broadcast.
  • sendStickyBroadcast()
  • sendStickyOrderedBroadcast()
  • apps need BROADCAST_STICKY permission to broadcast these.
  • use isInitialStickyBroadcast() to check for cached sticky broadcast.

• Alarms
  • mechanism to send intent at some point(s) in the future.
  • Can wake up a device.
  • Alarms are cancelled in case of shutdown.
• AlarmManager
  • getSystemService(ALARM_SERVICE)
  • set(type, triggerAtTime, PendingIntent);
  • setRepeating(type, triggerAtTime, interval, pendingIntent)
  • setInexactRepeating(…)

• Alarm types
  • How to interpret the time:
    • Realtime : number of millisecs since 1 Jan 1970
    • system up time.
  • Want to do when device sleeps:
    • wake the device: RTC_WAKEUP / ELAPSED_REALTIME_WAKEUP
    • wait for wake up: RTC / ELAPSED_REALTIME

• PendingIntent:
• create with:
  • getActivity(…)
  • getBroadcast(…)
  • getService(…)

• 2D graphics
  • ImageView
    • Simple, less flexible
  • Canvas
    • Complicated, more powerfull.
    • drawText(), drawPoints(), drawColor(), drawOval(), drawBitmap(), etc.
    • GenericView for less frequent drawning.
    • SurfaceView for frequent drawing.
      • Drawing on a surface.
      • Subclass must implement SurfaceHolder.Callback
      • surfaceCreated()
      • surfaceChanged()
      • surfaceDestroyed()
      • to Draw:
        • SurfaceHolder.lockCanvas()
        • Canvas.drawBitmap(), etc
        • SurfaceHolder.unlockCanvasAndPost()

• Drawable class:
  • ShapeDrawable
    • PathShape
    • RectShape
    • OvalShape
  • BitmapDrawable
  • ColorDrawable

• View animation
  • size, position, transparency, etc…
  • TransitionDrawable
    • 2-layers drawable
  • AnimationDrawable
    • Show each frame for some time.
  • Animation
    • transformation of content of a view.

• Property animation
  • ValueAnimator
    • Contains a TimeInterpolator
    • AnimatorUpdateListener
    • TypeEvaluator
    • AnimatorSet
    • ViewPropertyAnimator

• MotionEvents
  • Action code
    • ACTION_DOWN
    • ACTION_POINTER_DOWN
    • ACTION_POINTER_UP
    • ACTION_MOVE
    • ACTION_UP
    • ACTION_CANCEL
    • getActionMasked()
    • getActionIndex()
    • getPointerId(index)
    • getPointerCount()
    • getX(pindex)
    • getY(pindex)
    • findPointerIndex(pid)
  • time of event
  • device
  • location
  • pressure
  • MultiTouch:
    • Pointers with an unique ID

• Touch Handling
  • View.onTouchEvent()
  • View.OnTouchListener

• Gestures
  • GestureDetector
  • GestureDetector.OnGestureListener
  • GestureOverlayView
  • GestureLibraries.fromRawResource(…)

• Audio, Images, Movies
  • AudioManager, SoundPool
    • getSystemService(Context.AUDIO_SERVICE)
    • Load and play sound effects
    • manage volume
    • SoundPool can mix streams
  • RingtoneManager, Ringtone
  • MediaPlayer
    • Playback of audio and video streams and files.
    • setDataSource()
    • prepare()
    • start()/pause()
    • seekTo()
    • stop()
    • release()
  • VideoView
  • MediaRecorder
    • setAudioSource()
    • setVideoSource()
    • setOutputFormat()
    • prepare()
    • start()
    • stop()
    • release()
• Use camera
  • need uses-permission
  • need uses-feature for camera
  • get camera instance
  • set camera parameters
  • setup preview display
  • start preview
  • take a picture and process image data
  • release camera