Broadcastreceiver (broadcast)

What is radio , The role of broadcasting ,Android Why design radio ？

  In short , Broadcast is a mechanism for information feedback in applications , Broadcasting needs the help of BroadcastReceiver（ Broadcast receivers ） receive , When sent , All have been registered BroadcastReceiver Will check the registration IntentFilter Whether it is related to the sent Intent（intent3.setAction（xx）） Match , If it matches, it will call BroadcastReceiver Class onReceive（） Method , And Activity The components are different , When the system passes Intent Startup specifies Activity When the component , If the system does not find the right Activity when , Cause program to terminate abnormally , But the system did not find the right BroadcastReceiver Components , There is nothing wrong with the application .

Broadcasting is divided into ordinary broadcasting , Orderly broadcasting and asynchronous broadcasting

Ordinary and orderly are the same and different ： The broadcast receiving order of the same level is random , After receiving the low-level broadcast , And dynamic registration at the same level is higher than static registration . Ordinary broadcasting cannot transmit the processing result to the next receiver and cannot stop broadcasting , Orderly broadcasting can .

The use of radio , Send a broadcast , Receive a broadcast

// Create a class , The interface is simple, and the sending is common , Orderly , Asynchronous broadcast

public class MainActivity extends Activity {


	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		// Dynamically register broadcast recipients BroadcastReceiver
//		IntentFilter intentfilter = new IntentFilter("BC_One");
//		BC2 bc2 = 	new BC2();
//		registerReceiver(bc2, intentfilter);
	}
	public void doClick(View v){
		switch (v.getId()) {
		case R.id.send1:// Send a normal broadcast 
			Intent intent = new Intent();
			intent.putExtra("msg", " This is an ordinary broadcast ");
			// And registration BroadcastReceiver At the time of the IntentFilter Of <action android:name="BC_One" /> Corresponding 
			intent.setAction("BC_One");
			sendBroadcast(intent);// Send general broadcast 
			break;


		case R.id.send2:// Send a normal broadcast   
			Intent intent2 = new Intent();
			intent2.putExtra("msg", " This is an orderly broadcast ");
			intent2.setAction("BC_One");
			sendOrderedBroadcast(intent2, null);// Send an orderly broadcast 
			break;
		case R.id.send3:// Send a normal broadcast 
			Intent intent3 = new Intent();
			intent3.putExtra("msg", " This is an asynchronous broadcast ");
			intent3.setAction("BC_Three");
			sendStickyBroadcast(intent3);// Send asynchronous broadcast 
			// Asynchronous broadcasting can be sent first and then registered , But remember to add permissions <uses-permission android:name="android.permission.BROADCAST_STICKY"/>
			IntentFilter intentfilter = new IntentFilter("BC_Three");
			BC3 bc3 = 	new BC3();
			registerReceiver(bc3, intentfilter);
			
			break;
		}
	}
	@Override
	protected void onDestroy() {
		// TODO Auto-generated method stub
		super.onDestroy(); 
		// Uninstall broadcast 
//		unregisterReceiver(receiver);
	}
}

BC1,BC2,BC3 Three categories

public class BC1 extends BroadcastReceiver{

	@Override
	public void onReceive(Context context, Intent intent) {
		String s = intent.getStringExtra("msg");
		System.out.println("reveiver1 Received a message ："+s);
		//abortBroadcast();// Execute interrupt broadcast , Contrast the difference between ordinary and orderly 
		// Processing dissemination data 
		Bundle bundle = 	new Bundle();
		bundle.putString("test", " Broadcast processed data ");
		setResultExtras(bundle);
	}

}

public class BC2 extends BroadcastReceiver{

	@Override
	public void onReceive(Context context, Intent intent) {
		String s = intent.getStringExtra("msg");
		System.out.println("reveiver2 Received a message ："+s);
		
		Bundle bundle = getResultExtras(true);
		String s2 = bundle.getString("test");
		System.out.println(" The result is ："+s2);
	}

}

public class BC3 extends BroadcastReceiver{

	@Override
	public void onReceive(Context context, Intent intent) {
		System.out.println(" Received asynchronous broadcast !");
	}

}

Static configuration BroadcastReceiver Methods

<application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.imooc.broadcastreceiverdemo.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <receiver android:name="com.imooc.broadcastreceiverdemo.BC1" >
            <intent-filter>
                <action android:name="BC_One" />
            </intent-filter>
        </receiver>
        <receiver android:name="com.imooc.broadcastreceiverdemo.BC2" >
            <intent-filter>
                <action android:name="BC_One" />
            </intent-filter>
        </receiver>
    </application>

Click the normal broadcast button to run the results

Click the result of the send order button

// Whether the test is terminated

// Test whether the information can be processed

The result of clicking the asynchronous send button