Android Broadcast 廣播

進程內本地廣播

　　如果你是在你的應用之內使用廣播，即不需要跨進程，考慮使用LocalBroadcastManager ，這樣更有效率（因為不需要跨進程通信），並且你不用考慮一些其他應用可以發送或接收你的廣播相關的安全問題。

　　下面介紹更一般的方法。

廣播的兩種注冊方法

　　廣播有靜態和動態兩種注冊方法：

　　靜態注冊：在AndroidManifest.xml中加上<receiver> 標簽。

　　動態注冊：通過 Context.registerReceiver()方法進行注冊。比如在onResume中注冊，在onPause中注銷。

　　附上例子（例子中的布局、MyReceiver類，常量類都是相同的，在前面列出）：

　　布局文件都一樣：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".DemoBroadcastActivity" >

    <TextView
        android:id="@+id/helloText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <Button
        android:id="@+id/sendBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/helloText"
        android:text="@string/send" />

</RelativeLayout>

　　自己寫的Receiver類：

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

public class MyReceiver extends BroadcastReceiver
{

    
    public MyReceiver()
    {
        super();
        Log.d(AppConstants.LOG_TAG, "Receiver constructor");
    }

    @Override
    public void onReceive(Context context, Intent intent)
    {
        Log.d(AppConstants.LOG_TAG, "onReceive");
        String message = intent.getStringExtra(AppConstants.MSG_KEY);
        Log.i(AppConstants.LOG_TAG, message);
        Toast.makeText(context, "Received! msg: " + message, Toast.LENGTH_SHORT).show();
    }
    
    

}

　　應用常量：

public class AppConstants
{
    public static final String LOG_TAG = "Broadcast";
    public static final String MSG_KEY = "msg";
    
    public static final String BROADCAST_ACTION ="com.example.demobroadcast.BroadcastAction";

}

　　下面就是不同的部分了！

　　靜態注冊的實例代碼：

　　靜態注冊是在manifest文件中進行:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.demobroadcast"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

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

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.demobroadcast.DemoBroadcastActivity"
            android:label="@string/app_name" >
            <intent-filter android:priority="1000">
                <action android:name="android.intent.action.MAIN" />

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

        <receiver
            android:name="com.example.demobroadcast.MyReceiver">
            <intent-filter  >
                <action android:name="com.example.demobroadcast.BroadcastAction" />
            </intent-filter>
        </receiver>
    </application>

</manifest>

　　所以Java代碼：

package com.example.demobroadcast;

import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import android.app.Activity;
import android.content.Intent;

public class DemoBroadcastActivity extends Activity
{
    private Button sendBtn = null;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_demo_broadcast);

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

        sendBtn.setOnClickListener(new OnClickListener()
        {

            @Override
            public void onClick(View v)
            {
                Intent intent = new Intent();
                intent.setAction(AppConstants.BROADCAST_ACTION);
                intent.putExtra("msg", "聖騎士wind");
                sendBroadcast(intent);

            }
        });
    }

}

　　動態注冊的實例代碼:

　　動態注冊是在Java代碼中進行：

package com.example.demobroadcast2;

import com.example.demobroadcast.R;

import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import android.app.Activity;
import android.content.Intent;
import android.content.IntentFilter;

public class DemoBroadcastActivity extends Activity
{
    private Button sendBtn = null;
    
    private MyReceiver mReceiver;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_demo_broadcast);

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

        sendBtn.setOnClickListener(new OnClickListener()
        {

            @Override
            public void onClick(View v)
            {
                Intent intent = new Intent();
                intent.setAction(AppConstants.BROADCAST_ACTION);
                intent.putExtra("msg", "聖騎士wind");
                sendBroadcast(intent);

            }
        });
    }
    
    @Override
    protected void onResume()
    {
        super.onResume();
        
        mReceiver = new MyReceiver();
        IntentFilter intentFilter= new IntentFilter(AppConstants.BROADCAST_ACTION);
        registerReceiver(mReceiver, intentFilter);
    }
    
    @Override
    protected void onPause()
    {
        super.onPause();
        
        unregisterReceiver(mReceiver);
    }
    
    @Override
    protected void onDestroy()
    {
        super.onDestroy();
    }

}