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);
     }
 }

MainActivity.java

 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);
     }

 }

Service.java

 <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>

activity_main.xml

 <?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>

AndroidManifest.xml