Android_BroadcastReceiver广播接收者详解及应用
16lz
2021-01-26
1.概述
广播接收者(BroadcastReceiver)用于接收广播,在Android系统中,广播应用非常常见。例如当开机完成后系统会产生一条action为android.intent.action.BOOT_COMPLETED的广播,可达到开机启动的目的;当手机接收到一条短信,系统会产生一条action为android.provider.Telephony.SMS_RECEIVED的广播,接收到这条广播就对短信进行处理 等等。
动态广播接收器比静态广播接收器要接受的早,可以尝试在AndroidManifest.xml静态和java代码动态注册广播接收者~~降低被杀死的概率
2.简单实现广播接收者
//1.继承BroadcastReceiver,覆写onReceive方法,intent包含广播对象信息public class SmsReceiver extends BroadcastReceiver {@Overridepublic void onReceive(Context context, Intent intent) {/* * 简要动作,一般不超过10秒 * ...To Do.. */}}
3.广播类型
(1).普通广播
//发送一个广播,所以监听该广播的广播接收者都可以监听到改广播public void click(View view){Intent intent = new Intent(this, SmsReceiver.class);sendBroadcast(intent);}
(2).异步广播
/* * 在onCreate()使用registerReceiver(BroadcastReceiver, IntentFilter)注册,但要注意在onDestroy()要解除注册 *///1.在onCreate注册receiver@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);IntentFilter filter = new IntentFilter();filter.addAction("baidu.myreceiver");registerReceiver(receiver, filter);}//2.在onDestroy要解除注册receiver@Overrideprotected void onDestroy() {unregisterReceiver(receiver);super.onDestroy();}
(3).有序广播
有序广播可以终止,无序的广播不可以终止!/* * 按照接收者的优先级顺序接收广播,取值范围为1000到-1000,值越大,优先级越高,安卓系统关键接收者默认为0, * 优先级可以在xml文件的intent-filter标签中的 priority 中声明。 */public class MainActivity extends Activity {public void click(View view){Intent intent = new Intent();intent.setAction("com.baidu.smsreceiver");//1.1.发送一个有序广播sendOrderedBroadcast(intent, receiverPermission);//1.2.发送一条有序广播,为该广播添加一些属性,resultReceiver为最终执行的接收者,即使abortBroadcast();也要执行sendOrderedBroadcast(intent, receiverPermission, resultReceiver, scheduler, initialCode, initialData, initialExtras)}}public class SmsReceiver extends BroadcastReceiver {@Overridepublic void onReceive(Context context, Intent intent) {Object[] objs = (Object[]) intent.getExtras().get("pdus");for(Object obj: objs){SmsMessage smsMessage = SmsMessage.createFromPdu((byte[])obj);String content = smsMessage.getMessageBody();String number = smsMessage.getOriginatingAddress();}abortBroadcast();//终止向下一个接收者传递}}
4.注册广播
(1).静态注册
(2).动态注册
使用动态注册的生命周期与应用相关,而静态注册则周期更长,即使应用没有被启动,在监听到需要接收的广播时,也可以接收!查看上面的一步广播,注意:注册之后,在当前activity销毁时在onDestroy()中解除注册
5.自定义permission
//1.sendBroadcast一个广播并接收一个使用权限public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);}public void click(View view){Toast.makeText(this, "Ok~!!~", 1).show();Intent intent = new Intent();intent.setAction("com.baidu.smsreceiver");sendBroadcast(intent, "baidu.permission");//为该广播添加一个权限,但需要在该项目的项目清单文件中定义及添加权限}}
<?xml version="1.0" encoding="utf-8"?>
//3.接收者继承BroadcastReceiver,覆写onReceive方法public class SmsReceiver extends BroadcastReceiver {@Overridepublic void onReceive(Context context, Intent intent) {// ...}}
<?xml version="1.0" encoding="utf-8"?>
6.应用
(1).短信窃听器
/** 1.继承BroadcastReceiver,覆写onReceive方法*/public class SmsReceiver extends BroadcastReceiver {@Overridepublic void onReceive(Context context, Intent intent) {//1.1接收到短信信息,get("pdus"),可能包含多条短信信息,故用数组表示Object[] objs = (Object[]) intent.getExtras().get("pdus");for(Object obj: objs){//1.2转换为每条短信的byte[] 得到smsMessage对象SmsMessage smsMessage = SmsMessage.createFromPdu((byte[])obj);//1.3对短信操作,获得关键数据String content = smsMessage.getMessageBody();//短信内容String number = smsMessage.getOriginatingAddress();//短信号码if("110".equals(number)){abortBroadcast();//终止广播向下传递SmsManager manager = SmsManager.getDefault();//得到Sms短信管理器//转发一条短信,需要声明权限manager.sendTextMessage("5556", null, "Kill", null, null);}System.out.println("content="+content);System.out.println("number="+number);}Toast.makeText(context, "OK!", Toast.LENGTH_SHORT).show();}}
(2).电话拨打器
public class TextReceiver extends BroadcastReceiver {@Overridepublic void onReceive(Context context, Intent intent) {//得到拨打电话号码String number = getResultData();//处理拨打的电话号码setResultData("010"+number);System.out.println(number);}}
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