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广播接收器:

 

广播接收者(BroadcastReceiver)用于监听系统事件或应用程序事件,通过调用Context.sendBroadcast()Context.sendOrderedBroadcast()可以向系统发送广播意图,通过广播一个意图(Intent)可以被多个广播接收者所接收,从而可以在不用修改原始的应用程序的情况下,让你对事件作出反应。

       其中Context.sendBroad()主要是用来广播无序事件(也被称为有序广播 Normal broadcast),即所有的接收者在理论上是同时接收到事件,同时执行的,对消息传递的效率而言这是比较好的做法。而Context.sendOrderedBroadcast()方法用来向系统广播有序事件(Ordered broadcast),接收者按照在Manifest.xml文件中设置的接收顺序依次接收Intent,顺序执行的,接收的优先级可以在系统配置文件中设置(声明在intent-filter元素的android:priority属性中,数值越大优先级别越高,其取值范围为-10001000。当然也可以在调用IntentFilter对象的setPriority()方法进行设置)。对于有序广播而言,前面的接收者可以对接收到得广播意图(Intent)进行处理,并将处理结果放置到广播意图中,然后传递给下一个接收者,当然前面的接收者有权终止广播的进一步传播。如果广播被前面的接收者终止后,后面的接收器就再也无法接收到广播了。

 

广播接收器(Broadcaset)运行的线程:

       无论对于有序广播还是无序广播,广播接收器默认都是运行在主线程中的(main线程,即UI线程)。可以通过在程序中使用registerReceiver(receiver, filter, broadcastPermission, scheduler)方法中的最后一个参数指定要运行的广播接收器的线程。也可以在Manifest.xml文件中设置(Intent-filter标签中设置android:process)

 

无序广播(Normal Broadcast)

       基本步骤:写一个类继承BroadcastReceiver,并重写onReceive方法,而后在AndroidManifest.xml文中中进行配置,或者直接在代码中注册。

      

下面是一个广播接收器的Demo(用于发送和接收短信)

      

import android.content.BroadcastReceiver;

import android.content.Context;

import android.content.Intent;

import android.os.Bundle;

import android.telephony.SmsMessage;

import android.util.Log;

 

public class ReceivingSMSReceiver extends BroadcastReceiver {

    private static final String SMS_RECEIVED = "android.provider.Telephony.SMS_RECEIVED";

    private static final String TAG = "ReceivingSMSReceiver";

 

    @Override

    public void onReceive(Context context, Intent intent) {

       if (intent.getAction().equals(SMS_RECEIVED)) {

           Bundle bundle = intent.getExtras();

           if (bundle != null) {

              Object[] pdus = (Object[]) bundle.get("pdus");

              SmsMessage[] messages = new SmsMessage[pdus.length];

              for (int i = 0; i < pdus.length; i++)

                  messages[i] = SmsMessage.createFromPdu((byte[]) pdus[i]);

              for (SmsMessage message : messages) {

                  String msg = message.getMessageBody();

                  Log.i(TAG, msg);

                  String to = message.getOriginatingAddress();

                  Log.i(TAG, to);

              }

           }

       }

    }

}

 

AndroidManifest.xml文件中的<application>节点里对接收到短信的广播Intent进行注册:

<receiver android:name=". ReceivingSMSReceiver">

<intent-filter>

<action android:name="android.provider.Telephony.SMS_RECEIVED"/>

</intent-filter>

</receiver>

AndroidManifest.xml文件中添加以下权限:

<uses-permission android:name="android.permission.RECEIVE_SMS"/><!-- 接收短信权限 -->

 

该广播接收器将首先得到本机收到的短信,可以对短信内容进行过滤。

 

在模拟器中运行该工程。

 

建立一个新的Android工程,新建一个Activity用来发送短信:

 

import android.app.Activity;

import android.app.PendingIntent;

import android.content.BroadcastReceiver;

import android.content.Context;

import android.content.Intent;

import android.content.IntentFilter;

import android.os.Bundle;

import android.telephony.SmsManager;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

import android.widget.Toast;

 

public class SMSSender extends Activity {

    private static final String TAG = "SMSSender";

    Button send = null;

    EditText address = null;

    EditText content = null;

    private mServiceReceiver mReceiver01, mReceiver02;

    private static String SEND_ACTIOIN = "SMS_SEND_ACTION";

    private static String DELIVERED_ACTION = "SMS_DELIVERED_ACTION";

 

    @Override

    protected void onCreate(Bundle savedInstanceState) {

       super.onCreate(savedInstanceState);

       setContentView(R.layout.main);

       address = (EditText) findViewById(R.id.address);

       content = (EditText) findViewById(R.id.content);

       send = (Button) findViewById(R.id.send);

       send.setOnClickListener(new View.OnClickListener() {

 

           @Override

           public void onClick(View v) {

              // TODO Auto-generated method stub

              String mAddress = address.getText().toString().trim();

              String mContent = content.getText().toString().trim();

              if ("".equals(mAddress) || "".equals(mContent)) {

                  Toast.makeText(SMSSender.this, "发送地址为空或内容为空!",

                         Toast.LENGTH_LONG).show();

                  return;

              }

              SmsManager smsManager = SmsManager.getDefault();

              try {

                  Intent send_Intent = new Intent(SEND_ACTIOIN);

                  Intent deliver_Intent = new Intent(DELIVERED_ACTION);

                  PendingIntent mSend = PendingIntent.getBroadcast(

                         getApplicationContext(), 0, send_Intent, 0);

                  PendingIntent mDeliver = PendingIntent.getBroadcast(

                         getApplicationContext(), 0, deliver_Intent, 0);

                  smsManager.sendTextMessage(mAddress, null, mContent, mSend,

                         mDeliver);

              } catch (Exception e) {

                  e.printStackTrace();

              }

           }

       });

    }

 

    @Override

    protected void onResume() {

       // TODO Auto-generated method stub

       IntentFilter mFilter01;

       mFilter01 = new IntentFilter(SEND_ACTIOIN);

       mReceiver01 = new mServiceReceiver();

       registerReceiver(mReceiver01, mFilter01);

       mFilter01 = new IntentFilter(DELIVERED_ACTION);

       mReceiver02 = new mServiceReceiver();

       registerReceiver(mReceiver02, mFilter01);

       super.onResume();

    }

 

    @Override

    protected void onPause() {

       // TODO Auto-generated method stub

       unregisterReceiver(mReceiver01);

       unregisterReceiver(mReceiver02);

       super.onPause();

    }

 

    public class mServiceReceiver extends BroadcastReceiver {

       @Override

       public void onReceive(Context context, Intent intent) {

           // TODO Auto-generated method stub

           if (intent.getAction().equals(SEND_ACTIOIN)) {

              try {

                  switch (getResultCode()) {

                  case Activity.RESULT_OK:

                     break;

                  case SmsManager.RESULT_ERROR_GENERIC_FAILURE:

                     break;

                  case SmsManager.RESULT_ERROR_RADIO_OFF:

                     break;

                  case SmsManager.RESULT_ERROR_NULL_PDU:

                     break;

                  }

              } catch (Exception e) {

                  e.getStackTrace();

              }

           } else if (intent.getAction().equals(DELIVERED_ACTION)) {

              try {

                  switch (getResultCode()) {

                  case Activity.RESULT_OK:

                     break;

                  case SmsManager.RESULT_ERROR_GENERIC_FAILURE:

                     break;

                  case SmsManager.RESULT_ERROR_RADIO_OFF:

                     break;

                  case SmsManager.RESULT_ERROR_NULL_PDU:

                     break;

                  }

              } catch (Exception e) {

                  e.getStackTrace();

              }

           }

       }

    }

}

 

界面布局:

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:orientation="vertical" android:layout_width="fill_parent"

    android:layout_height="fill_parent">

    <TextView android:layout_width="fill_parent"

       android:layout_height="wrap_content" android:text="发送短信" />

    <TextView android:text="收信人地址:" android:id="@+id/textView1"

       android:layout_width="wrap_content" android:layout_height="wrap_content"></TextView>

    <EditText android:text="" android:layout_width="match_parent"

       android:id="@+id/address" android:layout_height="wrap_content"></EditText>

    <TextView android:text="短信内容:" android:id="@+id/textView2"

       android:layout_width="wrap_content" android:layout_height="wrap_content"></TextView>

    <EditText android:text="" android:layout_width="match_parent"

       android:id="@+id/content" android:layout_height="wrap_content"></EditText>

    <Button android:text="发送" android:id="@+id/send"

       android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>

</LinearLayout>

 

AndroidManifest.xml文件中增加对该Activity的配置:

<activity android:name=".SMSSender" android:label="@string/app_name">

           <intent-filter>

              <action android:name="android.intent.action.MAIN" />

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

           </intent-filter>

       </activity>

AndroidManifest.xml文件中添加以下权限:

<uses-permission android:name="android.permission.SEND_SMS"/><!—发送短信权限 -->

 

在另一个模拟器中运行该工程。

 

由于本文的重点内容并不是发送和接收短信,所以,对短信发送和接收的内容并没有详细解释。如果对短信收发内容不熟悉的朋友,可以查阅相关文档。

 

 

有序广播:

 

接收器1

import android.content.BroadcastReceiver;

import android.content.Context;

import android.content.Intent;

import android.os.Bundle;

 

public class BroadcastTest2 extends BroadcastReceiver {

 

    @Override

    public void onReceive(Context arg0, Intent arg1) {

       System.out.println("运行线程:    " + Thread.currentThread().getId() + "   "

              + Thread.currentThread().getName());

       System.out.println("广播意图的动作: " + arg1.getAction());

       Bundle bundle = new Bundle();

       bundle.putString("test", "zhongnan");

       setResultExtras(bundle);

    }

}

 

接收器2

import android.content.BroadcastReceiver;

import android.content.Context;

import android.content.Intent;

import android.os.Bundle;

 

public class BroadcastTest1 extends BroadcastReceiver {

 

    @Override

    public void onReceive(Context arg0, Intent arg1) {

       System.out.println("运行线程:    " + Thread.currentThread().getId() + "   "

              + Thread.currentThread().getName());

       System.out.println("广播意图的动作: " + arg1.getAction());

       Bundle bundle = getResultExtras(false);

      

       if (bundle == null) {

           System.out.println("没有得到上次传递的数据");

       } else {

           System.out.println("测试: " + bundle.getString("test"));

       }

    }

}

 

Activity,用来发送广播:

import android.app.Activity;

import android.content.Intent;

import android.os.Bundle;

 

public class MainActivity extends Activity {

    /** Called when the activity is first created. */

    @Override

    public void onCreate(Bundle savedInstanceState) {

       super.onCreate(savedInstanceState);

       setContentView(R.layout.main);

       this.sendOrderedBroadcast(new Intent(

              "android.provier.zhongnan.broadcast"), null);

    }

}

 

AndroidManifest.xml文件:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.zhongnan.bc" android:versionCode="1" android:versionName="1.0">

    <uses-sdk android:minSdkVersion="8" />

    <application android:icon="@drawable/icon" android:label="@string/app_name">

       <activity android:name=".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=".BroadcastTest1">

           <intent-filter>

              <action android:name="android.provier.zhongnan.broadcast"

                  android:priority="400" />

           </intent-filter>

       </receiver>

       <receiver android:name=".BroadcastTest2">

           <intent-filter>

              <action android:name="android.provier.zhongnan.broadcast"

                  android:priority="500" />

           </intent-filter>

       </receiver>

    </application>

</manifest>

 

MainActivity中发送有序广播Context.sendOrderedBroadcast(),由于BroadcastTest2中设置的接收优先级比较高,所以在BroadcastTest2中将首先接收到广播意图,可以在BroadcastTest2中对该广播意图进行处理,可以加入处理后的数据给后面的接收器使用,也可以在该接收器中终止广播的进一步传递。在广播中加入处理后的数据使用setResultExtras(Bundle bundle)方法,关于Bundle类,类似于HashMap,不熟悉的朋友可以参考文档,或者查看我的另一篇博客。在后面的接收器中使用getResultExtras(boolean flag)接收前面的接收器存放的数据,其中的boolean参数含义为:true代表如果前面的接收器没有存放数据,则自动创建一个空的Bundle对象,false则表示如果前面的接收器如果没有存放任何数据则返回null

 

广播接收器中权限的定义:

    在发送广播时,无论是无序广播(Normal Broadcast)还是有序广播(Ordered Broadcast)都有类似的方法: sendBroadcast (Intent intent, String receiverPermission), sendOrderedBroadcast (Intent intent, String receiverPermission)。其中第二个参数是设置权限,即接收器必须具有相应的权限才能正常接收到广播。

 

下面是在上述例子的基础上添加自定义权限的例子:

         接收器1

import android.content.BroadcastReceiver;

import android.content.Context;

import android.content.Intent;

import android.os.Bundle;

 

public class BroadcastTest2 extends BroadcastReceiver {

 

    @Override

    public void onReceive(Context arg0, Intent arg1) {

       System.out.println("运行线程:    " + Thread.currentThread().getId() + "   "

              + Thread.currentThread().getName());

       System.out.println("广播意图的动作: " + arg1.getAction());

       Bundle bundle = new Bundle();

       bundle.putString("test", "zhongnan");

       setResultExtras(bundle);

    }

}

 

接收器2

import android.content.BroadcastReceiver;

import android.content.Context;

import android.content.Intent;

import android.os.Bundle;

 

public class BroadcastTest1 extends BroadcastReceiver {

 

    @Override

    public void onReceive(Context arg0, Intent arg1) {

       System.out.println("运行线程:    " + Thread.currentThread().getId() + "   "

              + Thread.currentThread().getName());

       System.out.println("广播意图的动作: " + arg1.getAction());

       Bundle bundle = getResultExtras(false);

      

       if (bundle == null) {

           System.out.println("没有得到上次传递的数据");

       } else {

           System.out.println("测试: " + bundle.getString("test"));

       }

    }

}

 

Activity,用来发送广播:

import android.app.Activity;

import android.content.Intent;

import android.os.Bundle;

 

public class MainActivity extends Activity {

    /** Called when the activity is first created. */

    @Override

    public void onCreate(Bundle savedInstanceState) {

       super.onCreate(savedInstanceState);

       setContentView(R.layout.main);

       this.sendOrderedBroadcast(new Intent(

              "android.provier.zhongnan.broadcast"), "xzq.zhongnan.test");

    }

}

代码中与上述例子最大的差别在于MainActivity中发送广播的代码: this.sendOrderedBroadcast(new Intent(

              "android.provier.zhongnan.broadcast"), "xzq.zhongnan.test")增加了自定义的一个权限。

AndroidManifest文件中配置自定义的权限:

    <permission android:protectionLevel="normal" android:name="xzq.zhongnan.test"></permission>

关于如何在工程中自定义权限请查阅相关文档,或查看我的另一篇博客。

相应的,接收器中必须设置接收权限:

<uses-permission android:name="xzq.zhongnan.test"></uses-permission>

这样,接收器就可以正确接收到广播了。

 

 

 

 

另外,上述程序已讲到,BroadcastReceiver是允许在主线程中的,所以,在onReceive方法中执行的代码,运行时间不能超过5s,否则将报出程序没有相应的异常,如果要执行的代码运行的时间比较长,可以使用Service组件。

转自:
http://blog.csdn.net/zhongnan09/article/details/6552632

posted on 2012-06-07 23:09 小果子 阅读(2812) 评论(0)  编辑 收藏 引用 所属分类: Android & Ios

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