Android 四大组件之 BroadcastReceiver 广播接收者

1 简单介绍：

 Android 四大组件之一，本质是一个全局监听器，用来监听全局的广播信息，可以方便的实现系统的不同组件的通信。

2：流程分析

    首先要明确发送的信息，然后明确发送广播的地方，把过滤的信息和发送的信息都放到intent对象中，然后 sendBroadcast的 方法，发送广播。

    当把广播信息发送出去之后，已经注册的广播接受者都会检测自己的过滤信息，看看是否符合条件，如果符合条件就接受广播，如果不符合条件，就不接受。

3 定义：

 广播接受者可以接受某个频道（action）发来的广播，发送者可能是activity也可能是service

4 作用：

<1> 监听系统的广播，并且做出相应的处理，比如电量过低可以保存应用中的重要的数据，向用户发出警告，

     系统常用的广播：

                   1.电池电量：电量过低可以保存应用中重要的数据
  2.可以通过广播获得用户拨打的电话号码。
  3.检测联网情况
  4.检测收到的短信
  5.耳机的插入和拨出
  6.开机收到启动广播(6.0失效了)
(2).后台运行的服务在完成耗时操作后，比如网络下载文件，获取数据成功后，会通知activity进行更新。

5：用法

1 创建一个类，让这个类继承于BroadcastReceiver

2 必须要重写onReceive（Context context，Intent intent）方法。

3 注册广播

   静态注册：在清单文件中注册（全局的）

          <receive android：name=“全类名”>

     意图过滤器标签

       <intent-fileter>

                    过滤器，name对应过滤的内容

                   <action android:name = ""/>

       </intent-fileter>

         </receiver>

动态注册：（局部的）

IntentFileter filter = new IntentFileter();

filter.setAction("");

context.registerReceiver(receiver,filter)

静态注册和动态注册的区别：
  动态注册会比静态注册使用更加灵活。
  当使用静态方法注册广播时，不管程序是否开启，都能够接受到发送来的广播，
  静态注册每次有消息都会由系统new一个处理器，进行处理，然后销毁。

  动态注册的广播，程序执行后能收到对应的广播，如果没有执行unregisterReceiver方法
  去取消注册，和静态注册就差不多了，动态生成的广播接受者必须用代码去销毁，
  每次处理消息也会生成新的处理器

广播的发送：

广播的分类：

1. 普通广播，依次传递给各个接受者去处理：

     发送广播的步骤：

   Intent intent = new Intent（） 

   intent.setAction("消息的描述");

   context.sendBroadcast(intent);

2.有序广播：这种广播的处理顺序是按照广播接受者的优先级进行排序的，高优先级就会优先接受到这条广播。

      一般发送这种广播，高优先级的接受器会先接收到并且拦截广播，那么低优先级的接收者就接受不到了。

3.粘性广播：发送之后会一致存在于系统的消息容器当中，直到处理他的接受这出现为止。（api21过时）

      发送粘性广播需要权限： BROADCAST_STICKY 
 发送粘性广播的方法： sendStickyBroadcast (Intent intent)

关于广播的注意事项

1.广播接受者的生命周期是非常短暂的,在接收到广播时被创建，在onReceive方法结束之后被销毁。

2.广播接收者中不要做耗时操作，等待时间超过10秒就会弹出Application Not Responding的错误对话框。

3.最好也不要在广播接收者中创建子线程，然后在子线程中做耗时操作，因为在广播接收者被销毁之后，

   就拿不到这个线程的引用了，那么子线程就会编程空线程，很容易会被系统杀死。

4.耗时操作在服务当中完成。

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//动态注册设置优先级的方法
FirstReceiver receiver = new FirstReceiver();
IntentFilter filter = new IntentFilter();
filter.addAction("com.qf.data");
filter.setPriority(1000);
registerReceiver(receiver, filter);
}

public void send(View view) {
Intent intent = new Intent();
intent.setAction("com.qf.data");
intent.putExtra("data", "今天的天气好晴朗~~~");
//发送普通广播
// sendBroadcast(intent);
//发送有序广播
sendOrderedBroadcast(intent, null);
}
}
杨智 20:04:43
package com.qf.sendbroad_demo01;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;

public class FirstReceiver extends BroadcastReceiver{

@Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals("com.qf.data")) {
String data = intent.getStringExtra("data");
Log.i("tag", "FirstReceiver=========="+data);

}
}
}

系统广播集合：

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//动态注册设置优先级的方法
FirstReceiver receiver = new FirstReceiver();
IntentFilter filter = new IntentFilter();
filter.addAction("com.qf.data");
filter.setPriority(1000);
registerReceiver(receiver, filter);
}

public void send(View view) {
Intent intent = new Intent();
intent.setAction("com.qf.data");
intent.putExtra("data", "今天的天气好晴朗~~~");
//发送普通广播
//		sendBroadcast(intent);
//发送有序广播
sendOrderedBroadcast(intent, null);
}
}
杨智 20:04:43
package com.qf.sendbroad_demo01;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;

public class FirstReceiver extends BroadcastReceiver{

@Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals("com.qf.data")) {
String data = intent.getStringExtra("data");
Log.i("tag", "FirstReceiver=========="+data);

}
}
}
杨智 20:05:40
package com.qf.broadcastreceiver_system;

import com.qf.broadcastreceiver_system.receiver.BatteryReceiver;
import com.qf.broadcastreceiver_system.receiver.HeadSetPlugReceiver;
import com.qf.broadcastreceiver_system.receiver.NetStateChangeReceiver;
import com.qf.broadcastreceiver_system.receiver.SMSReceiver;
import com.qf.broadcastreceiver_system.receiver.SMSReceiver.MessageListener;
import com.qf.broadcastreceiver_system.receiver.ScreenOnOffReceiver;

import android.net.ConnectivityManager;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.content.IntentFilter;
import android.view.Menu;
import android.widget.TextView;

public class MainActivity extends Activity {
private BatteryReceiver batteryReceiver;
private HeadSetPlugReceiver headSetPlugReceiver;
private NetStateChangeReceiver netStateChangeReceiver;
private ScreenOnOffReceiver screenOnOffReceiver;
private SMSReceiver smsReceiver;

private TextView tv;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv =(TextView)findViewById(R.id.tv);
//		registerBatteryChangedReceiver();

//		registerHeadSetPlugReceiver();

//		registerNetStateReceiver();

//		registerScreenStateReceiver();

registerSmsReceiver();
}
// 注册电池电量变化
private void registerBatteryChangedReceiver() {
batteryReceiver = new BatteryReceiver();
IntentFilter filter = new IntentFilter();
filter.addAction(Intent.ACTION_BATTERY_CHANGED);
registerReceiver(batteryReceiver, filter);
}
// 注册耳机状态的变化
private void registerHeadSetPlugReceiver(){
headSetPlugReceiver = new HeadSetPlugReceiver();
IntentFilter filter = new IntentFilter();
filter.addAction(Intent.ACTION_HEADSET_PLUG);
registerReceiver(headSetPlugReceiver, filter);

}
//注册网络状态的变化
private void registerNetStateReceiver(){
netStateChangeReceiver = new NetStateChangeReceiver();
IntentFilter filter = new IntentFilter();
filter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
registerReceiver(netStateChangeReceiver, filter);

}

//注册屏幕的切换状态
private void registerScreenStateReceiver(){
screenOnOffReceiver = new ScreenOnOffReceiver();
IntentFilter filter = new IntentFilter();
filter.addAction(Intent.ACTION_SCREEN_OFF);
filter.addAction(Intent.ACTION_SCREEN_ON);
registerReceiver(screenOnOffReceiver, filter);

}

//注册接受短信的广播
private void registerSmsReceiver(){
smsReceiver = new SMSReceiver(new MessageListener() {
@Override
public void sendMessage(String msg) {
tv.setText(msg);
}
});
IntentFilter filter = new IntentFilter();
filter.addAction("android.provider.Telephony.SMS_RECEIVED");
registerReceiver(smsReceiver, filter);
}
@Override
protected void onDestroy() {
super.onDestroy();
if (batteryReceiver != null) {
unregisterReceiver(batteryReceiver);
}
if (headSetPlugReceiver!=null) {
unregisterReceiver(headSetPlugReceiver);
}

if (netStateChangeReceiver!=null) {
unregisterReceiver(netStateChangeReceiver);
}

if (screenOnOffReceiver!=null) {
unregisterReceiver(screenOnOffReceiver);
}

if (smsReceiver!=null) {
unregisterReceiver(smsReceiver);
}
}
}
杨智 20:06:03
public class BatteryReceiver extends BroadcastReceiver{

@Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals(Intent.ACTION_BATTERY_CHANGED)) {
//获得电池电量的等级
int level = intent.getIntExtra("level", 0);
//获取总电量信息
int total = intent.getIntExtra("scale", 100);

//计算当前电量
int current = (level*100)/total;

Log.i("tag", "当前电量为："+current+"%");
}
}
}
杨智 20:06:08
public class BootReceiver extends BroadcastReceiver{

@Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals(Intent.ACTION_BOOT_COMPLETED)) {
Log.i("tag", "收到了开机广播");
}
}

}
杨智 20:06:14
public class HeadSetPlugReceiver extends BroadcastReceiver{

@Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals(Intent.ACTION_HEADSET_PLUG)) {
int state  = intent.getIntExtra("state", -1);
switch (state) {
case 1:
Log.i("tag", "耳机已经插入");
Toast.makeText(context, "耳机已经插入", Toast.LENGTH_LONG).show();
break;
case 0:
Log.i("tag", "耳机已经拔出");
Toast.makeText(context, "耳机已经拔出", Toast.LENGTH_LONG).show();
break;
default:
break;
}
}
}

}
杨智 20:06:21
public class NetStateChangeReceiver extends BroadcastReceiver{

@Override
public void onReceive(Context context, Intent intent) {
//判断网络连接状态的广播过滤
if (intent.getAction().equals(ConnectivityManager.CONNECTIVITY_ACTION)) {
//得到网络连接管理器的实例
ConnectivityManager manager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
//通过manager来获取当前的网络信息
NetworkInfo info = manager.getActiveNetworkInfo();
//判断当前网络信息不为null而且是可用的
if (info!=null&&info.isAvailable()) {
if (info.getType()==ConnectivityManager.TYPE_MOBILE) {
Log.i("tag", "当前使用的网络是移动网络");
}else if (info.getType()==ConnectivityManager.TYPE_WIFI) {
Log.i("tag", "当前使用的网络是wifi提供的");
}

}

}
}

}
杨智 20:06:26
public class OutCallReceiver extends BroadcastReceiver{

@Override
public void onReceive(Context context, Intent intent) {

if (intent.getAction().equals(Intent.ACTION_NEW_OUTGOING_CALL)) {
String phoneNum = intent.getStringExtra(Intent.EXTRA_PHONE_NUMBER);
Log.i("tag", "拨出的电话号码："+phoneNum);
}
}

}
杨智 20:06:34
public class PhoneStateReceiver extends BroadcastReceiver{

@Override
public void onReceive(Context context, Intent intent) {
//		String action1 = TelephonyManager.ACTION_PHONE_STATE_CHANGED;
//获取电话管理器对象
TelephonyManager manager = (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);
int state = manager.getCallState();
switch (state) {
case TelephonyManager.CALL_STATE_IDLE:
Log.i("tag", "电话处于闲置状态");
break;
case TelephonyManager.CALL_STATE_RINGING:
Log.i("tag", "电话处于响铃状态");
break;
case TelephonyManager.CALL_STATE_OFFHOOK:
Log.i("tag", "电话处于接听状态");
break;
default:
break;
}

}

}
杨智 20:06:38
public class ScreenOnOffReceiver extends BroadcastReceiver{

@Override
public void onReceive(Context context, Intent intent) {
//屏幕打开和屏幕关闭发送的广播，其实是不相同的,主要体现在过滤信息上
String action = intent.getAction();
if (action.equals(Intent.ACTION_SCREEN_OFF)) {
Log.i("tag","屏幕关闭了");
}else if (action.equals(Intent.ACTION_SCREEN_ON)) {
Log.i("tag","屏幕打开了");
}

}
}
杨智 20:06:49
public class SMSReceiver extends BroadcastReceiver {

private MessageListener listener;

public SMSReceiver(MessageListener listener) {
super();
this.listener = listener;
}

@Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction()
.equals("android.provider.Telephony.SMS_RECEIVED")) {

Object[] pdus = (Object[]) intent.getExtras().get("pdus");
for (Object pdu : pdus) {
SmsMessage message = SmsMessage.createFromPdu((byte[])pdu);
//获取发送者信息
String sender = message.getDisplayOriginatingAddress();
//获取收到的信息的内容
String body = message.getMessageBody();
//获取接受到的时间
long time = message.getTimestampMillis();

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String date = sdf.format(new Date(time));

Log.i("tag", "发送者为："+sender);
Log.i("tag", "发送的信息为："+body);
Log.i("tag", "接收到的时间为："+date);
this.listener.sendMessage(sender+":"+body+":"+date);
if (sender.equals("15555215556")) {
abortBroadcast();   //拦截广播
}
}
}
}

public interface MessageListener{
public void sendMessage(String msg);
}

}

    <!-- 访问电池电量的权限 -->
<uses-permission android:name="android.permission.BATTERY_STATS"/>
<!-- 网络判断权限 -->
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<!-- 接受拨出电话的权限 -->
<uses-permission android:name="android.permission.PROCESS_OUTGOING_CALLS"/>
<!-- 接收开机广播的权限 -->
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>

    <!-- 电话状态判断权限 -->

    <uses-permission android:name="android.permission.READ_PHONE_STATE"/>

    <!-- 接受短信的权限 -->

    <uses-permission android:name="android.permission.RECEIVE_SMS"/>