android service broadcastreceiver intentfilter

service 组件，和UI并不进行交互，运行在后台，可以和其他组件进行交互

broadcastreceiver，广播是一种广泛运用的在应用程序之间传输信息的机制 。而 BroadcastReceiver 是对发送出来的广播进行过滤接收并响应的一类组件

intentfilter Intent类似于Windows中的消息，而intentfilter可以理解为消息过滤器

下面我们用例子来说明如何运用这三种组件

首先，我们建立一个Serivce，他的作用是每间隔一秒生成一个随机数，并将随机数放到Intent中

然后声明一个action,在Service中进行广播，在MainActivity中来接收这个广播，并显示随机数.

为了可以使服务停止，我们另外建立了一个BroadCastReceiver 来接受广播，当判断广播内容是停止服务时，调用停止服务.

在服务的onCreate中，注册广播接收器组件，在onDestory中取消注册广播接收组件

在onStartCommand中声明了一个IntentFilter用来过滤广播消息，设定Action

先来看下Service和停止服务用的BroadCastReceiver 

package com.ssln.broadcastreceiver_service_intentfilter;

import android.app.Service;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.IBinder;
import android.util.Log;

public class MyService extends Service {

    public final static int CMD_STOP_SERVICE=1;    //停止服务
    private CommandReciver cmdReceiver;
    private boolean flag;
    public final static String action="com.ssln.broadcastreceiver_service_intentfilter.MyService";
    private static final String TAG = "MyService";

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onCreate() {
        flag = true;
        cmdReceiver = new CommandReciver();
        super.onCreate();
        Log.i(TAG, "MyService-->onCreate");
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.i(TAG, "MyService-->onStartCommand");
        IntentFilter filter = new IntentFilter(); // 建立IntentFilter对象
        filter.addAction(action);
        // 注册广播接收，并设置接受的action
        registerReceiver(cmdReceiver, filter);
        Log.i(TAG, "MyService-->注册BroadcastReceiver成功");
        // 启动线程
        doJob();
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public void onDestroy() {
        Log.i(TAG, "MyService-->onDestroy");
        // 取消广播接受的注册
        unregisterReceiver(cmdReceiver);
        Log.i(TAG, "MyService-->取消注册BroadcastReceiver成功");
        super.onDestroy();
    }

    /**
     * 执行线程
     */
    private void doJob() {
        new Thread() {
            public void run() {
                while (flag) {
                    try {
                        Thread.sleep(1000);// 睡眠一秒
                    } catch (Exception exp) {
                        exp.printStackTrace();
                    }
                    Intent intent=new Intent();
                    //设置action
                    intent.setAction(action);
                    //设置随机数
                    intent.putExtra("data", Math.random());
                    //发送广播
                    sendBroadcast(intent);
                    Log.i(TAG, "MyService-->doJob");
                }
            }

        }.start();
    }

    /**
     * 为了Service的停止，为Service注册Broadcast Receiver组件
     * @author ssln
     *
     */
    private class CommandReciver extends BroadcastReceiver {

        @Override
        public void onReceive(Context context, Intent intent) {
            int cmd=intent.getExtras().getInt("cmd",-1);
            if(cmd==CMD_STOP_SERVICE){
                //停止线程
                flag=false;
                //停止服务
                stopSelf();
            }
        }

    }
}

在来看看MainActivity.java

在onclick中，我们看到btnStart是启动了我们自定义的服务，而btnStop是发送了一个停止服务的广播内容

package com.ssln.broadcastreceiver_service_intentfilter;

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.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends Activity implements OnClickListener{

    private static final String TAG = "MainActivity";
    private TextView tvData;
    private Button btnStart,btnStop;
    private DataReceiver datareceiver;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tvData=(TextView)findViewById(R.id.tvData);
        btnStart=(Button)findViewById(R.id.btnStart);
        btnStop=(Button)findViewById(R.id.btnStop);
        
        btnStart.setOnClickListener(this);
        btnStop.setOnClickListener(this);
    }
 
    /**
     * 注册广播接收
     */
    private void RegDataReceiver()
    {
        if(datareceiver==null)
        {
            //注册action
            datareceiver=new DataReceiver();
            IntentFilter filter=new IntentFilter();
            //添加接受的action
            filter.addAction(MyService.action);
            //注册
            registerReceiver(datareceiver, filter);
            Log.i(TAG, "注册广播成功");
        }
    }
    /**
     * 取消注册
     */
    private void UnRegDataReceiver()
    {
        if(datareceiver!=null)
        {
            unregisterReceiver(datareceiver);
            datareceiver=null;
            Log.i(TAG, "取消注册广播");
        }
    }

    @Override
    protected void onResume() {
        RegDataReceiver();
        Log.i(TAG, "onResume");
        super.onResume();
    }

    @Override
    protected void onPause() {
        UnRegDataReceiver();
        Log.i(TAG, "onPause");
        super.onPause();
    }


    /**
     * 接受线程发送过来的数据
     * @author ssln
     *
     */
    private class DataReceiver extends BroadcastReceiver{

        @Override
        public void onReceive(Context context, Intent intent) {
            double data=intent.getDoubleExtra("data", 0.0d);
            if(data==0)
            {
                int cmd=intent.getIntExtra("cmd", -1);
                if(cmd==MyService.CMD_STOP_SERVICE)
                    tvData.setText("停止服务成功");
                else
                    tvData.setText("未知数据");
            }
            else
            {
                tvData.setText("Service 发送的数据为: "+String.valueOf(data));
            }
        }
        
    }

    @Override
    public void onClick(View v) {
        if(v==btnStart)
        {
            Intent myIntent=new Intent(MainActivity.this,MyService.class);
            startService(myIntent);
            tvData.setText("启动服务成功 ");
        }
        else if(v==btnStop)
        {
            Intent myIntent=new Intent();
            myIntent.setAction(MyService.action);
            myIntent.putExtra("cmd", MyService.CMD_STOP_SERVICE);
            sendBroadcast(myIntent);
        }
    }
}

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/LinearLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.ssln.broadcastreceiver_service_intentfilter.MainActivity" >

    <TextView
        android:id="@+id/tvData"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView" />

    <Button
        android:id="@+id/btnStart"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="启动服务" />

    <Button
        android:id="@+id/btnStop"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="停止服务" />

</LinearLayout>

最后，记得在AndroidManifest.xml中注册我们的服务，否则启动不了的啊

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

    <uses-sdk
        android:minSdkVersion="17"
        android:targetSdkVersion="20" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <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>
        <!-- 注册服务 -->
        <service android:name="MyService"></service>
    </application>

</manifest>

看下效果,每秒生成的随机数都不同

我们点击停止后，会停止服务