Android - Basic Steps (Notifications)

User Notifications

Types:

• Toast
• Notification Area Notifications

Tip

To use the notification vibration, establish the permission in the AndroidManifest.xml file

   <uses-permission android:name="android.permission.VIBRATE" >

    </uses-permission>

Broadcast

• Base class for components that receive and react to events
• When event occur is represented as Intent, then are broadcast to system
• The Intent routes to BroadcastReceiver
• The BroadcastReceiver receive on the method onReceive()

Broadcast

• Events can be broadcast in Order or Normal way
• Normal - Undefined order and if there are two or more BroadcastReceivers can process the event at the same time.
• Order - Deliver the intent one at the time in priority order
• Can also be Sticky or Not Sticky
• Sticky  
• Store intent after initial broadcast
• Is useful to record system changes like the battery status
• Is disposed after the event finish 
• Non Sticky
• Discard intent after initial broadcast
• Is useful to record that an event has occurred
• The broadcaster must have the permission BROADCAST_STICKY

Broadcast Order

To send the Intent in an order can use the method sendOrderedBroadcast()

• With two parameters send in priority order (Intent intent, String receivingpermission)
• With more parameters have better control

BroadcastReceiver

• The broadcastReceiver can register in
• AndroidManifest (Statically)
• Atributes  - android:exported - if can receive from other applications
• It is registered when system boot or when package are added at runtime.
• The mehods to register at runtime are:
• Context.registerReceiver()
• LocalBroadcastManager.registerReceiver()
• Using the method registerRecewiver()  (Dinamically)

        <receiver

            android:name=".Receiver"

            android:exported="false" >

            <intent-filter>

                <action android:name="course.examples.BroadcastReceiver.show_toast" >

                </action>

            </intent-filter>

        </receiver>

• BroadcastReceiver 
• Receive on the method onReceive() with the context and intent as parameter
• broadcast an intent is a relative expensive 
• broadcast runs in the main thread 
• Receiver is not consider valid once onReceive() returns
• Broadcast receivers can't start asynchronous operations 
• When the method sendOrderedBroadcast is invoke, it can collect information from others broadcastReceiver with the method getResultData()

new BroadcastReceiver() {

@Override

public void onReceive(Context context, Intent intent) {

Toast.makeText(context,

"Final Result is " + getResultData(),

Toast.LENGTH_LONG).show();

}

}, null, 0, null, null);

• In each broadcastReceiver can put data with the method 

setResultData(info_to_be_collected);

Debug

• Get more information in the Log using in the Intent to be broadcast
• Intent.setFlag(FLAG_DEBUG_LOG_RESOLUTION)
• Use ADB tool 
• To see which receivers are registed
• Use dumpsys command
• %adb shell dumpsys activity b
• show broadcast receivers that are dynamically registered
• %adb shell dumpsys package
• show broadcast receivers that are statically registered