BroadcastReceiver基礎應用

本文來自人人網android開發交流羣

前面分別討論了Activity和Service，這次就輪到BroastcastReceiver，Broastcast是應用程序間通信的手段。BroastcastReceiver也是跟Intent緊密相連的，動態/靜態註冊了BroastcastReceiver之後，使用sendBroadcast把Intent發送之後，系統會自動把符合條件的BroastcastReceiver啓動，跟嵌入式系統的中斷類似。
 

     本文主要演示瞭如何靜態/動態註冊BroastcastReceiver，向系統索取電量信息，以及枚舉信息的字段。本文運行截圖如下：
 

 
上圖是發送Intent至內部動態註冊的BroadcastReceiver，接收到之後顯示消息名稱。動態註冊BroadcastReceiver用到registerReceiver()。
 
上圖是發送Intent至內部靜態註冊的BroadcastReceiver，接收到之後顯示消息名稱。靜態註冊比動態註冊麻煩點，先新建一個類繼承BroadcastReceiver，然後到AndroidManifest.xml添加

<receiver android:name="clsReceiver2">  
    <intent-filter>  
        <action  
            android:name="com.testBroadcastReceiver.Internal_2"/>  
    </intent-filter>  
</receiver> 

第一個name是類名，第二個是action的名稱。
 

上圖是枚舉Intent消息的字段，這個功能比較適合懶人，把收到的Intent消息的字段全部分解了，再看看哪個需要的，懶得記住。實現這部分的代碼如下：

//當未知Intent包含的內容，則需要通過以下方法來列舉   
                Bundle b=intent.getExtras();   
                Object[] lstName=b.keySet().toArray();   
  
                for(int i=0;i<lstName.length;i++)   
                {   
                    String keyName=lstName.toString();   
                    Log.e(keyName,String.valueOf(b.get(keyName)));   
                } 

main.xml的代碼如下：

<?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">  
  
    <Button android:id="@+id/Button01" android:layout_width="wrap_content"  
        android:layout_height="wrap_content" android:text="發送至內部動態註冊的BroadcastReceiver"></Button>  
    <Button android:id="@+id/Button02" android:layout_width="wrap_content"  
        android:layout_height="wrap_content" android:text="發送至內部靜態註冊BroadcastReceiver"></Button>  
    <Button android:id="@+id/Button03" android:layout_width="wrap_content"  
        android:layout_height="wrap_content" android:text="發送至系統BroadcastReceiver"></Button>  
</LinearLayout>  

testBroadcastReceiver.java的代碼如下：

package com.testBroadcastReceiver;   
  
import android.app.Activity;   
import android.content.BroadcastReceiver;   
import android.content.Context;   
import android.content.Intent;   
import android.content.IntentFilter;   
import android.os.Bundle;   
import android.util.Log;   
import android.view.View;   
import android.widget.Button;   
import android.widget.Toast;   
  
public class testBroadcastReceiver extends Activity {   
    Button btnInternal1,btnInternal2,btnSystem;   
    static final String INTENAL_ACTION_1 = "com.testBroadcastReceiver.Internal_1";   
    static final String INTENAL_ACTION_2 = "com.testBroadcastReceiver.Internal_2";   
    static final String INTENAL_ACTION_3 = "com.testBroadcastReceiver.Internal_3";   
    @Override  
    public void onCreate(Bundle savedInstanceState) {   
        super.onCreate(savedInstanceState);   
        setContentView(R.layout.main);   
        btnInternal1=(Button)this.findViewById(R.id.Button01);   
        btnInternal1.setOnClickListener(new ClickEvent());   
        btnInternal2=(Button)this.findViewById(R.id.Button02);   
        btnInternal2.setOnClickListener(new ClickEvent());   
        btnSystem=(Button)this.findViewById(R.id.Button03);   
        btnSystem.setOnClickListener(new ClickEvent());   
        //動態註冊廣播消息   
        registerReceiver(bcrIntenal1, new IntentFilter(INTENAL_ACTION_1));   
    }   
    class ClickEvent implements View.OnClickListener{   
  
        @Override  
        public void onClick(View v) {   
            if(v==btnInternal1)//給動態註冊的BroadcastReceiver發送數據   
            {   
                Intent intent = new Intent(INTENAL_ACTION_1);   
                sendBroadcast(intent);   
            }   
            else if(v==btnInternal2)//給靜態註冊的BroadcastReceiver發送數據   
            {   
                Intent intent = new Intent(INTENAL_ACTION_2);   
                sendBroadcast(intent);   
            }   
            else if(v==btnSystem)//動態註冊 接收2組信息的BroadcastReceiver   
            {   
                IntentFilter filter = new IntentFilter();//   
                filter.addAction(Intent.ACTION_BATTERY_CHANGED);//系統電量檢測信息   
                filter.addAction(INTENAL_ACTION_3);//第三組自定義消息   
                registerReceiver(batInfoReceiver, filter);   
                   
                Intent intent = new Intent(INTENAL_ACTION_3);   
                intent.putExtra("Name", "hellogv");   
                intent.putExtra("Blog", "http://blog.csdn.net/hellogv");   
                sendBroadcast(intent);//傳遞過去   
            }   
        }   
           
    }   
       
      
    private BroadcastReceiver bcrIntenal1 = new BroadcastReceiver() {   
           
        public void onReceive(Context context, Intent intent) {   
            String action = intent.getAction();   
            Toast.makeText(context, "動態:"+action, 1000).show();   
        }   
    };   
       
  
    private BroadcastReceiver batInfoReceiver = new BroadcastReceiver() {   
           
        public void onReceive(Context context, Intent intent) {   
            String action = intent.getAction();   
            //如果捕捉到的action是ACTION_BATTERY_CHANGED   
            if (Intent.ACTION_BATTERY_CHANGED.equals(action)) {   
                //當未知Intent包含的內容，則需要通過以下方法來列舉   
                Bundle b=intent.getExtras();   
                Object[] lstName=b.keySet().toArray();   
  
                for(int i=0;i<lstName.length;i++)   
                {   
                    String keyName=lstName.toString();   
                    Log.e(keyName,String.valueOf(b.get(keyName)));   
                }   
            }   
            //如果捕捉到的action是INTENAL_ACTION_3   
            if (INTENAL_ACTION_3.equals(action)) {   
                //當未知Intent包含的內容，則需要通過以下方法來列舉   
                Bundle b=intent.getExtras();   
                Object[] lstName=b.keySet().toArray();   
  
                for(int i=0;i<lstName.length;i++)   
                {   
                    String keyName=lstName.toString();   
                    Log.e(keyName,b.getString(keyName));   
                }   
            }   
        }   
    };   
  
  
}  

clsReceiver2.java的代碼如下：

package com.testBroadcastReceiver;   
  
import android.content.BroadcastReceiver;   
import android.content.Context;   
import android.content.Intent;   
import android.widget.Toast;   
  
  
public class clsReceiver2 extends BroadcastReceiver{   
    @Override  
    public void onReceive(Context context, Intent intent) {   
        String action = intent.getAction();   
        Toast.makeText(context, "靜態:"+action, 1000).show();   
           
    }   
}