1. Broadcast type: standard broadcast and ordered broadcast . Standard broadcasts are asynchronous broadcasts that are received almost at the same time by all receivers after broadcast, without sequencing, high efficiency, but cannot be truncated. An ordered broadcast is a synchronous broadcast that only one receiver receives this message at the same time, and then continues to pass after execution, and the priority receiver can accept it and truncate the broadcast pass.
Dynamic Registration Case Study: Network change alertBuild Response Class: Class Networkchangereciver extends
Broadcastreceiver{ @Override public void OnReceive (context context, Intent Intent) { Connectivitymanager connectivitymanager= (Connectivitymanager) Getsystemservice (context.connectivity_ SERVICE); networkinfo networkinfo=connectivitymanager.getactivenetworkinfo (); if ((Networkinfo!=null&&networkinfo.isavailable ())) { &nBsp Toast.maketext (Context, "Network available", Toast.length_short). Show (); } else{ Toast.maketext (Context, "Network unavailable", Toast.length_short). Show (); }
} Register the response when creating the activity, and classify the filter message private Intentfilter intentfilter;//filter message private networkchangereciver networkchangereciver;
@Override protected void OnCreate (Bundle savedinstancestate) {super.oncreate (Savedinsta Ncestate); Setcontentview (R.layout.activity_main);
intentfilter=new Intentfilter (); intentfilter.addaction ("Android.net.conn.CONNECTIVITY_CHANGE"); networkchangereciver=new networkchangereciver (); registerreceiver (Networkchangereciver, Intentfilter); } destruction listener @Override protected void OnDestroy () { Super.ondestroy (); unregisterreceiver (Networkchangereciver); } finally added permissions to the configuration file <uses-permission android:name= " Android.permission.ACCESS_NETWORK_STATE "/>
Static registration Case studies (The benefit is that you can listen to the broadcast without starting the program)
Boot upDefines a listener class public class Bootcompletereceiver extends Broadcastreceiver {@Override public void onreceive (Context conte Xt,intent Intent) {toast.maketext (context, "Start complete", Toast.length_short). Show (); }} Modify Android configuration file <?xml version= "1.0" encoding= "Utf-8"?> < manifest xmlns:android= "http://schemas.android.com /apk/res/android "package=" Com.example.zhb.test2 "> <uses-permission android:name=" Android.permission.ACCESS _network_state "/>
<uses-permission android:name= "Android.permission.RECEIVE_BOOT_COMPLETED"/><application android:allowbackup= "true" android:icon= "@drawable/ic_launcher" android:label= "@st Ring/app_name "Android:theme=" @style/apptheme ">
<receiver android:name= "Com.example.zhb.Com.BootCompleteReceiver" > <intent-filter> <action android:name= "Android.intent.action.BOOT_COMPLETED"/> </intent-filter> </r Eceiver><activity android:name= ". Mainactivity "android:label=" @string/app_name "> <intent-filter> <acti On android:name= "Android.intent.action.MAIN"/> <category android:name= "Android.intent.category.LAUN CHER "/> </intent-filter> </activity> </application> </manifest> 2. Send Standard broadcast and ordered broadcast
Standard broadcast :
Define a Receive broadcast class public class Mybroadcastreceiver extends Broadcastreceiver {@Override public void onreceive (Context context,inten T intent) {String Value=intent.getstringextra ("key"); Toast.maketext (Context,value,toast.length_short). Show (); } }
Configuration profile Information<receiver android:name= "Com.example.zhb.Com.MyBroadcastReceiver" > <intent-filter> <action android:name= "Com.example.broadcasttest.MY_BROADCAST"/> </intent-filter> </rece Iver>
send a message with dataButton Btnbrctestone = (button) Findviewbyid (R.id.btnbrctestone); Btnbrctestone.setonclicklistener (New View.onclicklistener () {@Override public void OnClick (View V {Intent Intent = new Intent ("Com.example.broadcasttest.MY_BROADCAST"); Intent.putextra ("Key", "I am the Broadcast news!") "); Sendbroadcast (Intent); } }
ordered Messages: Simply change one line of code @Override protected void OnCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate); Setcontentview (r.layout.brocasttest);
Button Btnbrctestone = (button) Findviewbyid (R.id.btnbrctestone); Btnbrctestone.setonclicklistener (New View.onclicklistener () {@Override public void OnClick (View V {Intent Intent = new Intent ("Com.example.broadcasttest.MY_BROADCAST"); Intent.putextra ("Key", "I am the Broadcast news!") "); Sendbroadcast (Intent);
Sendorderedbroadcast (intent,null);} } ); }
Set Priority Receive permissions<receiver android:name= "Com.example.zhb.Com.MyBroadcastReceiver" > <intent-filter
android:priority= "> <action android:name= "Com.example.broadcasttest.MY_BROADCAST"/> </intent-filter& Gt </receiver> truncate broadcast continues to propagate public class Mybroadcastreceiver extends Broadcastreceiver {@Override public void Onrec Eive (Context context,intent Intent) {String Value=intent.getstringextra ("key"); Toast.maketext (Context,value,toast.length_short). Show ();
abortbroadcast ();}} Local broadcast: All previous broadcasts are global broadcasts, that is, broadcasts that are issued can be received by any program, and can also be accepted for broadcast to any program. This can easily lead to security, such as data being monitored by other programs, or other programs that are constantly sending spam broadcasts. Therefore, there is a local broadcasting mechanism. Broadcasts can only be delivered within the application, and receivers can only receive broadcasts from the application. Local broadcasts cannot be registered in a configuration file by means of a static method. public class Brocasttest extends Activity {
Private
IntentfilterFilter for intentfilter;//frame private
Localreceiverlocalreceiver;//the custom receiver private
Localbroadcastmanagerlocalbroadcastmanager;//Framework's local broadcast manager
@Override protected void OnCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate); Setcontentview (r.layout.brocasttest);
Localbroadcastmanager=localbroadcastmanager.getinstance (this);//Get instance Button Btnbrctestone = (button) Findviewbyid (R.id.btnbrctestone); Btnbrctestone.setonclicklistener (New View.onclicklistener () {@Override public void onclic K (View v) {//Send local broadcast
Intent intent1=new Intent ("Com.example.broadcasttest.LOCAL_BROADCAST"); Localbroadcastmanager.sendbroadcast (intent1);} } );
intentfilter=new Intentfilter (); Intentfilter.addaction ("Com.example.broadcasttest.LOCAL_BROADCAST"); Localreceiver=new Localreceiver (); Localbroadcastmanager.registerreceiver (localreceiver,intentfilter);}
@Override protected void OnDestroy () {Super.ondestroy ();
Localbroadcastmanager.unregisterreceiver (localreceiver);}
Class Localreceiver extends
Broadcastreceiver{@Override public void onreceive (Context context,intent Intent) {Toast.maketext (cont Ext, "received local broadcast", Toast.length_short). Show (); } } }
Android Beginner to Skilled (v)---broadcast
