Android 广播 Broadcast学习

Android Broadcast 广播

进程内本地广播

　　如果你是在你的应用之内使用广播，即不需要跨进程，考虑使用LocalBroadcastManager ，这样更有效率（因为不需要跨进程通信），并且你不用考虑一些其他应用可以发送或接收你的广播相关的安全问题。

　　下面介绍更一般的方法。

广播的两种注册方法

　　广播有静态和动态两种注册方法：

　　静态注册：在AndroidManifest.xml中加上<receiver> 标签。

　　动态注册：通过 Context.registerReceiver()方法进行注册。比如在onResume中注册，在onPause中注销。

　　附上例子（例子中的布局、MyReceiver类，常量类都是相同的，在前面列出）：

　　布局文件都一样：

<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>

　　自己写的Receiver类：

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();
    }
    
    

}

　　应用常量：

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！

　　静态注册的实例代码：

　　静态注册是在manifest文件中进行:

<?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代码：

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", "圣骑士wind");
                sendBroadcast(intent);

            }
        });
    }

}

　　动态注册的实例代码:

　　动态注册是在Java代码中进行：

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", "圣骑士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();
    }

}