從頭學(xué)Android之BroadcastReceiver

1、BroadcastReceiver簡介BroadcastReceiver明白得為廣播接收者，它用于接收程序所發(fā)出的Broadcast的Intentc它在一端監(jiān)聽接收廣播消息，然后再做出處置。它的本質(zhì)上確實(shí)是屬于一個(gè)監(jiān)聽器。啟動(dòng)BroadcastRecevicer的方式有兩種：sendBroadcast()和sendOrderedBroadcast(),二者的區(qū)別確實(shí)是前者是發(fā)送一個(gè)一般的廣播，后者是發(fā)送一個(gè)有序的廣播。開發(fā)廣播接收才的步驟：1、繼承BroadcastReceiver類，重寫onReceiver(Contextcontext,Intentintent)方式2、在中注冊，一樣也能夠

2、在代碼中實(shí)現(xiàn)注冊3、通過sendBroadcast()或sendOrderedBroadcast()啟動(dòng)對應(yīng)的BroadcastReceiver下面別離介紹：實(shí)現(xiàn)廣播消息處置機(jī)制的方式繼承BroadcastReceiver,覆蓋onReceivejavaviewplaincopyprint?publicclassMyReceiverextendsBroadcastReceiverpublicMyReceiver()System.out.println(-myReceiverconstructor-);publicvoidonReceive(Contextcontext,Intentintent

3、)System.out.println(-onReceive-);/取到信息StringreceiveMsg=intent.getStringExtra(msg);Toast.makeText(context,receiveMsg,Toast.LENGTH_LONG).show();注冊BroadcastReceiver的兩種方式：方式一：中注冊：htmlviewplaincopyprint?方式二：應(yīng)用程序代碼中注冊javaviewplaincopyprint?myReceiver2=newMyReceiver2();IntentFilte門ntentFilter=newIntentFilt

4、er();Intentintent=newIntent();intentFilter.addAction(SMS_ACTION);registerReceiver(myReceiver2,intentFilter);兩種注冊方式的區(qū)別：1)第一種是常駐型，也確實(shí)是說當(dāng)應(yīng)用程序關(guān)閉后，若是有信息廣播來，程序也會被系統(tǒng)挪用自動(dòng)運(yùn)行。2)第二種不是常駐型廣播，也確實(shí)是說廣播跟從程序的生命周期。廣播的類型：廣播被分為兩種不同的類型：”一般廣播(Normalbroadcasts)和有序廣播(Orderedbroadcasts)”。一般廣播是完全異步的，能夠在同一時(shí)刻(邏輯上)被所有接收者接收到，消息傳遞

5、的效率比較高，但缺點(diǎn)是：接收者不能將處置結(jié)果傳遞給下一個(gè)接收者，而且無法終止廣播Intent的傳播；但是有序廣播是依照接收者聲明的優(yōu)先級別(聲明在intent-filter元素的android:priority屬性中，數(shù)越大優(yōu)先級別越高，取值范圍：-1000到1000。也能夠挪用IntentFilter對象的setPriority()進(jìn)行設(shè)置)，被接收者依次接收廣播。如：A的級別高于B,B的級別高于C,那么，廣播先傳給A,再彳專給B,最后傳給C。A取得廣播后，能夠往廣播里存入數(shù)據(jù)，當(dāng)廣播傳給B時(shí),B能夠從廣播中取得A存入的數(shù)據(jù)。Context.sendBroadcast()發(fā)送的是一般廣播，所

6、有定閱者都有機(jī)遇取得并進(jìn)行處置。Context.sendOrderedBroadcast()發(fā)送的是有序廣播，系統(tǒng)會依照接收者聲明的優(yōu)先級別按順序逐個(gè)執(zhí)行接收者，前面的接收者有權(quán)終止廣播(BroadcastReceiver.abortBroadcast(),若是廣播被前面的接收者終止，后面的接收者就再也無法獲取到廣播。關(guān)于有序廣播，前面的接收者能夠?qū)⑻幹媒Y(jié)果寄存進(jìn)廣播Intent,然后傳給下一個(gè)接收者。再總結(jié)說說兩種廣播的區(qū)別比較：一般廣播：異步，數(shù)據(jù)不共享，傳遞效率高有序廣播：同步，數(shù)據(jù)能夠達(dá)到共享，傳遞效率低說了這么一大堆，是不是都暈，那就上實(shí)例吧實(shí)例1:發(fā)送一般廣播1、寫一個(gè)繼承于Bro

7、adcastReceiver的類，并重寫onReceiver方式j(luò)avaviewplaincopyprint?packagecom.jiahui.broadcast;importandroid.content.BroadcastReceiver;importandroid.content.Context;importandroid.content.Intent;importandroid.widget.Toast;publicclassMyBroadcastReceiverextendsBroadcastReceiverOverridepublicvoidonReceive(Contextco

8、ntext,Intentintent)Toast.makeText(context,”接收到的Intent的Action為+intent.getAction()+n傳遞的消息內(nèi)容為+intent.getStringExtra(msg),Toast.LENGTH_LONG)在中注冊htmlviewplaincopyprint?5.在Activity中發(fā)送廣播javaviewplaincopyprint?packagecom.jiahui.broadcast;importandroid.app.Activity;importandroid.content.Intent;importandroid.

9、os.Bundle;importandroid.view.View;importandroid.widget.Button;publicclassBroadcastDemo1ActivityextendsActivitypublicvoidonCreate(BundlesavedInstanceState)super.onCreate(savedInstanceState);setContentView(R.layout.main);14.ButtonbtnSend=(Button)this.findViewByld(R.id.btnSend);btnSend.setOnClickListen

10、er(newView.OnClickListener()OverridepublicvoidonClick(Viewv)Intentintent=newIntent();/指定發(fā)送特定的BroadcastReceiverintent.setAction(com.jiahui.broadcast.mybroadcast);/帶一些消息內(nèi)容過去intent.putExtra(msg,我發(fā)過來的數(shù)據(jù)哦)；sendBroadcast(intent););實(shí)現(xiàn)成效:發(fā)送普通廣播發(fā)送普通廣播接收到的Intent的Adi?？跒閏om.JIdhuLbrodcast.mybrofidcast傳遞的消息內(nèi)容為我發(fā)

11、過來的數(shù)據(jù)啜實(shí)例2:發(fā)送有序廣播寫兩個(gè)BroadcastReceiver類MyReceiver01.java:javaviewplaincopyprint?packagecom.jiahui.broadcast;importandroid.content.BroadcastReceiver;importandroid.content.Context;importandroid.content.Intent;importandroid.os.Bundle;importandroid.widget.Toast;publicclassMyReceiver1extendsBroadcastReceiv

12、erpublicvoidonReceive(Contextcontext,Intentintent)System.out.println(MyReceiveU-onReceive-);StringreceiverMsg=intent.getStringExtra(msg);System.out.println(receiverMsg:+receiverMsg);Toast.makeText(context,”接收到的Intnet的action+intent.getAction()+n發(fā)過來的消息內(nèi)容:+receiverMsg,5000).show();Bundlebundle=newBundl

13、e();bundle.putString(first,第一個(gè)廣播接收者給的數(shù)據(jù))；/放入下一個(gè)結(jié)果中，讓下一個(gè)廣播接收者收到消息setResultExtras(bundle);javaviewplaincopyprint?packagecom.jiahui.broadcast;importandroid.content.BroadcastReceiver;importandroid.content.Context;importandroid.content.Intent;importandroid.os.Bundle;importandroid.widget.Toast;publicclass

14、MyReceiver2extendsBroadcastReceiverOverridepublicvoidonReceive(Contextcontext,Intentintent)System.out.println(-MyReceiver2-onReceive-);取到結(jié)果Bundlebundle=getResultExtras(true);StringreceiverMsg=bundle.getString(first);System.out.println(receiverMsg:+receiverMsg);Toast.makeText(context,”接收到的Intnet的acti

15、on+intent.getAction()+n發(fā)過來的消息內(nèi)容:+receiverMsg,5000).show();在中文件注冊，同時(shí)設(shè)置為優(yōu)先級htmlviewplaincopyprint?11.注意：那個(gè)地址兩個(gè)廣播接收者設(shè)置的action是一樣開發(fā)Activity在Activity中發(fā)送有序廣播消息javaviewplaincopyprint?packagecom.jiahui.broadcast;importandroid.app.Activity;importandroid.content.Intent;importandroid.os.Bundle;importandroid.vi

16、ew.View;importandroid.widget.Button;publicclassBroadcastDemo2ActivityextendsActivitypublicvoidonCreate(BundlesavedInstanceState)super.onCreate(savedInstanceState);setContentView(R.layout.main);ButtonbtnSend=(Button)this.findViewById(R.id.btnSend);btnSend.setOnClickListener(newView.OnClickListener()O

17、verridepublicvoidonClick(Viewv)20.Intentintent=newIntent();intent.setAction(com.jiahui.broadcast.myreceiver););intent.putExtra(msg,發(fā)給第一個(gè)接收者的數(shù)據(jù)發(fā)送有序廣播sendOrderedBroadcast(intent,null););實(shí)現(xiàn)成效：發(fā)送有序廣播接收到的Intnet的actionmmJlBhuLbroadcast.myreceIver發(fā)過來的消息內(nèi)容：發(fā)皓第一個(gè)接收者的數(shù)據(jù)當(dāng)一段時(shí)刻咱們就能夠夠看到又會彈出一個(gè)信息如以下圖:也能夠通過操縱臺監(jiān)視:11-140733pl-1407.3J11-14073111-14073JrSyste號?營taSystereceiverMsg發(fā)愴采一個(gè)幫收卷的數(shù)據(jù)