BroadcastReceiver（有序广播篇）

BroadcastReceiver所对应的广播分两类：普通广播和有序广播。

普通广播通过Context.sendBroadcast()方法来发送。它是完全异步的。

所有的receivers接收器的执行顺序不确定。    因此，所有的receivers接收器接收broadcast的顺序不确定。

这种方式效率更高。但是BroadcastReceiver无法使用setResult系列，getResult系列及abort系列API

有序广播是通过Context.sendOrderedBroadcast来发送。所有的receiver依次执行。

BroadcastReceiver可以使用setResult系列函数来结果传给下一个BroadcastReceiver，通过getResult系列函数来取得上个BroadcastReceiver返回的结果，并可以abort系列函数来让系统丢弃该广播让，使用该广播不再传送到别的BroadcastReceiver。

可以通过在intent-filter中设置android:priority属性来设置receiver的优先级。优先级相同的receiver其执行顺序不确定。

如果BroadcastReceiver是代码中注册的话，且其intent-filter拥有相同android:priority属性的话，先注册的将先收到广播。

主要函数

Public Methodsfinal voidabortBroadcast()

Sets the flag indicating that this receiver should abort the current broadcast; only works with broadcasts sent throughContext.sendOrderedBroadcast.

final voidclearAbortBroadcast()

Clears the flag indicating that this receiver should abort the current broadcast.

final booleangetAbortBroadcast()

Returns the flag indicating whether or not this receiver should abort the current broadcast.

final booleangetDebugUnregister()

Return the last value given to setDebugUnregister(boolean).

final intgetResultCode()

Retrieve the current result code, as set by the previous receiver.

final StringgetResultData()

Retrieve the current result data, as set by the previous receiver.

final BundlegetResultExtras(boolean makeMap)

Retrieve the current result extra data, as set by the previous receiver.

final BroadcastReceiver.PendingResultgoAsync()

This can be called by an application in onReceive(Context, Intent) to allow it to keep the broadcast active after returning from that function.

final booleanisInitialStickyBroadcast()

Returns true if the receiver is currently processing the initial value of a sticky broadcast -- that is, the value that was last broadcast and is currently held in the sticky cache, so this is not directly the result of a broadcast right now.

final booleanisOrderedBroadcast()

Returns true if the receiver is currently processing an ordered broadcast.

abstract voidonReceive(Context context, Intent intent)

This method is called when the BroadcastReceiver is receiving an Intent broadcast.

IBinderpeekService(Context myContext, Intent service)

Provide a binder to an already-running service.

final voidsetDebugUnregister(boolean debug)

Control inclusion of debugging help for mismatched calls to {@ Context#registerReceiver(BroadcastReceiver, IntentFilter) Context.registerReceiver()}.

final voidsetOrderedHint(boolean isOrdered)

For internal use, sets the hint about whether this BroadcastReceiver is running in ordered mode.

final voidsetResult(int code, String data, Bundle extras)

Change all of the result data returned from this broadcasts; only works with broadcasts sent throughContext.sendOrderedBroadcast.

final voidsetResultCode(int code)

Change the current result code of this broadcast; only works with broadcasts sent throughContext.sendOrderedBroadcast.

final voidsetResultData(String data)

Change the current result data of this broadcast; only works with broadcasts sent throughContext.sendOrderedBroadcast.

final voidsetResultExtras(Bundle extras)

Change the current result extras of this broadcast; only works with broadcasts sent throughContext.sendOrderedBroadcast.

以下是一个关于有序广播的实例。

实例1：

MainActivity.java文件

package com.teleca.robin.BroadcastReceiverExample;

import com.teleca.R;

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.os.Handler;

import android.util.Log;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.TextView;

public class MainActivity extends Activity {

TextView tv=null;

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main0);

        tv=(TextView)findViewById(R.id.TextView1);

        Button button = (Button) findViewById(R.id.Button1);

        

        OnClickListener listener = new OnClickListener() {

         public void onClick(View v) {

         sendBroadcast();

         }

        };

        button.setOnClickListener(listener);

    }

    protected void onResume()

    {

    super.onResume();

    registerMyReceivers();

    }

    protected void onStop()

    {

    unRegisterMyReceivers();

    super.onStop();

    }

    final static String ACTION_HELLO="com.teleca.robin.action.HELLO";

    final static String KEY_ORDER_DETAIL="orderDetail";

    void sendBroadcast()

    {

        Intent intent=new Intent(ACTION_HELLO);

        String receiverPermission=null;

        Handler scheduler=null;

        int initialCode=0;

        String initialData=null;

        Bundle initialExtras=new Bundle();

        sendOrderedBroadcast(intent, receiverPermission, resultReceiver, scheduler, 

        initialCode, initialData, initialExtras);

    }

    BroadcastReceiver receiverArray[]=new MyBroadcastReceiver[50];

    void registerMyReceivers()

    {

    int k=receiverArray.length;

    int priority=IntentFilter.SYSTEM_LOW_PRIORITY;

    for(int i=0;i<k;i++)

    {

    receiverArray[i]=new MyBroadcastReceiver();

        IntentFilter filter=new IntentFilter(ACTION_HELLO);

        filter.setPriority(priority);

    registerReceiver(receiverArray[i], filter);

    if((i+1)%5==0)

    priority++;

    }

    

    }

    void unRegisterMyReceivers()

    {

    int k=receiverArray.length;

    for(int i=0;i<k;i++)

    {

    if(receiverArray[i]!=null)

    {

    unregisterReceiver(receiverArray[i]);

    receiverArray[i]=null;

    }

    }

    }

    final static String tag="robin";

    BroadcastReceiver resultReceiver=new BroadcastReceiver() {

    @Override

    public void onReceive(Context arg0, Intent intent) {

    // TODO Auto-generated method stub

    StringBuffer strBuffer=new StringBuffer();

    int count=getResultCode();

    strBuffer.append("there are "+count+" student\n");

    strBuffer.append("the older are :"+getResultData()+"\n");

    strBuffer.append("the detail older are :"+getResultExtras(true).getString(KEY_ORDER_DETAIL));

    tv.setText(strBuffer.toString());

    }

    };

}

MyBroadcastReceiver.java文件

package com.teleca.robin.BroadcastReceiverExample;

import android.content.BroadcastReceiver;

import android.content.Context;

import android.content.Intent;

import android.os.Bundle;

import android.util.Log;

class MyBroadcastReceiver extends BroadcastReceiver {

static int SN=0;

int id=SN++;

final static String tag="robin";

@Override

public void onReceive(Context arg0, Intent intent) {

// TODO Auto-generated method stub

if(intent.getAction().equals(MainActivity.ACTION_HELLO))

{

int count=getResultCode()+1;

setResultCode(count);

Log.i(tag,"this is student"+id);

String str=getResultData();

if(str==null)

str=""+id;

else

str=str+" "+id;

setResultData(str);

Bundle b=getResultExtras(true);

str=b.getString(MainActivity.KEY_ORDER_DETAIL);

if(str==null)

str=""+id;

else

str=str+"->"+id;

b.putString(MainActivity.KEY_ORDER_DETAIL, str);

Log.i(tag,"str:"+str);

setResultExtras(b);

}

}

}

main0.xml文件

<?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"

    android:id="@+id/root"

    >

<TextView  

    android:layout_width="fill_parent" 

    android:layout_height="wrap_content" 

    android:background="#FF0000FF"

    android:minHeight="50dip"

    android:text="@string/BroadcastReceiverExample"

    android:id="@+id/TextView1"

    />

<Button android:text="@string/pressme" 

android:id="@+id/Button1" 

android:layout_width="wrap_content" android:layout_height="wrap_content"

></Button>

</LinearLayout>

AndroidManifest.xml中

<activity android:name="com.teleca.robin.BroadcastReceiverExample.MainActivity"

  android:label="@string/app_name"

         >

             <intent-filter>

                <action android:name="com.teleca.robin.Hello" />

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

            </intent-filter>

        </activity>