Aactivity和Service之间的通信

一、在activity中定义三个按钮 一个开启服务  一个关闭服务，还有一个是向服务发送广播

当创建出Serevice时先执行Service的onCreate（）创建服务后只执行一次 以后每次点击开启服务都不会再执行onCreate（）而是去执行onStartCommand（）停止服务时执行Service的onDestroy（）

 二、在Activity中点击发送广播键会向服务发送广播（本例采用LocalBroadcastManager发送和接受广播）服务接收广播吐司出“接收到activity的广播”。服务是在oncreate（）里边创建接受者不在onStartcommand（）里边创建是因为每次点击开启服务时都会执行onStartcommand（）    activity创建出service时在service中的oncreate（）里向activity发送广播   activity在oncreate（）里创建出接受者。

三、其实就是双方都有一个发送者和接收者

看代码

package com.qf.service01;

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.support.v4.content.LocalBroadcastManager;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends Activity {

    Intent serviceIntent;
    MyReceiver myReceiver;
    LocalBroadcastManager localBroadcastMgr;//本地广播管理器
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        serviceIntent=new Intent(getApplicationContext(),MyService.class);
        localBroadcastMgr=LocalBroadcastManager.getInstance(getApplicationContext());
        myReceiver=new MyReceiver();
        localBroadcastMgr.registerReceiver(myReceiver, new IntentFilter("com.qf.broadcast.disen_service"));
    }
    
    
    class MyReceiver extends BroadcastReceiver{
        @Override
        public void onReceive(Context context, Intent intent) {
            Toast.makeText(MainActivity.this, "收到service的广播", Toast.LENGTH_SHORT).show();
            
        }
    }

    public void start(View v) {
        startService(serviceIntent);
    }

    public void stop(View v) {
        stopService(serviceIntent);
    }
    public void startService(View v) {
        localBroadcastMgr=LocalBroadcastManager.getInstance(getApplicationContext());
        Intent intent1=new Intent("com.qf.broadcast.activity");

        localBroadcastMgr.sendBroadcast(intent1);
    }


    @Override
    protected void onDestroy() {
        super.onDestroy();
        
        //取消注册本地广播接收器
        localBroadcastMgr.unregisterReceiver(myReceiver);
    }
}

package com.qf.service01;

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.support.v4.content.LocalBroadcastManager;
import android.util.Log;
import android.widget.Toast;

public class MyService extends Service {

    LocalBroadcastManager localBroadcastMgr;//本地广播管理器
    MyReceiver myReceiver;
    public void onCreate() { //只执行一次，用于初始化Service
        super.onCreate();
        Log.i("debug", "onCreate");
        
        myReceiver=new MyReceiver();
        localBroadcastMgr=LocalBroadcastManager.getInstance(getApplicationContext());
        localBroadcastMgr.registerReceiver(myReceiver, new IntentFilter("com.qf.broadcast.activity"));
    }
    class MyReceiver extends BroadcastReceiver{
        @Override
        public void onReceive(Context context, Intent intent) {
            Toast.makeText(context, "收到activity的广播", Toast.LENGTH_SHORT).show();
            
        }
    }
    
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        // TODO 每次启动Service都会执行的方法，在此实现核心的功能
        Log.i("debug", "onStartCommand");        
    
         Intent intent1=new Intent("com.qf.broadcast.disen_service");
        localBroadcastMgr.sendBroadcast(intent1);    
        
        return super.onStartCommand(intent, flags, startId);
    }
    
    
    
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }
    
    @Override
    public void onDestroy() { //只执行一次，用于销毁Service组件
        super.onDestroy();
        Log.i("debug", "onDestroy");
        localBroadcastMgr.unregisterReceiver(myReceiver);
    }

}

<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=".MainActivity" >

    <Button
        android:id="@+id/btn1Id"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="start"
        android:text="启动服务" />
    
    <Button
        android:id="@+id/btn2Id"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="stop"
        android:text="停止服务" 
        android:layout_below="@id/btn1Id"/>
    <Button
        android:id="@+id/btn3Id"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="startService"
        android:layout_below="@id/btn2Id"
        android:text="向服务发广播" />

</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.qf.service01"
    android:versionCode="1"
    android:versionName="1.0" >

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

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.qf.service01.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Service组件 -->
       <service android:name="com.qf.service01.MyService"/>
    </application>

</manifest>