The broadcast mechanism in Android framework

First, the broadcast through the intent sent out

// Define a broadcast intent filter Private String action = "Com.xxx.demo.Broadcast.STATUS_CHANGED"; // Send broadcast New Intent (); Intent.setaction (action); Servicesimulation. this. Sendbroadcast (intent);

Second, define the Broadcasereceiver class that receives the broadcast

1, inherit from Android.content.BroadcastReceiver;

2, must implement its OnReceive method, and in which all the actions triggered;

 Public class extends broadcastreceiver{    /**     * This object is created when a broadcast is received and executes the OnReceive method,     * Once the OnReceive method is executed (return),     the object is destroyed (after the burn mechanism is read).     * The next time the broadcast is received, the object will be recreated again, and then the burn mechanism is executed again.      */     @Override    publicvoid  onreceive (context context, Intent Intent) {         // TODO do someing ...     }}

3, must register;

(1) Registration in Androidmanifest.xml (static registration):

    <ApplicationAndroid:allowbackup= "true"Android:icon= "@drawable/ic_launcher"Android:label= "@string/app_name"Android:theme= "@style/apptheme" >                <receiverAndroid:name=". Servicebroadcastreceiver ">            <Intent-filter>                <ActionAndroid:name= "Com.xxx.demo.Broadcast.STATUS_CHANGED"/>            </Intent-filter>        </receiver>        <!--exported receiver does not require permission -    </Application>

Note: You must make sure that the <action> Android:name property is a globally unique string!

(2) Register in code (dynamic registration):

1. Declaring a broadcast receiver

    // registering a servicesimulation broadcast receiver     servicebroadcastreceiver Receiver;
    // Status_changed is a channel for servicesimulation to send broadcasts.    Private Final Static String status_changed = "Com.xxx.demo.Broadcast.STATUS_CHANGED";

2, create Intentfilter object;

3, call Context.registerreceiver () method registration;

    /*** Register Servicesimulation's broadcast receiver*/    Private voidRegisterservicebroadcastreceiver () {//instantiate the broadcast sink object receiver, which is a class member variableReceiver =NewServicebroadcastreceiver (); //Create an intent filter objectIntentfilter filter =NewIntentfilter (); //set the action for the intent filter object, that is: Broadcast channelfilter.addaction (status_changed); //Register the broadcast receiverMainactivity. This. Registerreceiver (receiver, filter); }

3. Call the Context.unregisterreceiver () method to log off.

    /**      * Unregister Servicesimulation's broadcast receiver      */     privatevoid  Unregisterservicebroadcastreceiver () {                //  logoff broadcast sink object receiver, the object is a class member variable        Mainactivity.  This . Unregisterreceiver (receiver);    }

Iii. contents of the broadcast

When calling Context.sendbroadcast (intent) to send a broadcast, the data can be transmitted by wrapping the specific broadcast content in the parameter intent.

The broadcast mechanism in Android framework