Android成长日记-Android四大组件之Service组件的学习

1、什么是Service?

Service是Android四大组件中与Activity最相似的组件,它们都代表可执行的程序,Service与Activity的区别在于:Service一直在后台运行,它没有用户界面,所以绝不会到前台来。一旦Service被启动起来,它就与Activity一样。它完全具有自己的生命周期。

service

       A Service is an application component that can perform long-running operations in the background and does not provide a user interface. Another application component can start a service and it will continue to run in the background even if the user switches to another application. Additionally, a component can bind to a service to interact with it and even perform interprocess communication (IPC). For example, a service might handle network transactions, play music, perform file I/O, or interact with a content provider, all from the background.   (来自官方解释:http://developer.android.com/guide/components/services.html)

2.小编经过查阅资料,以下是Service的相关资料:

定义:后台运行,不可见,没有界面
          优先级高于Activity
用途:
        播放音乐,记录地理信息位置的改变,监听某种动作.....
注意:
         运行在主线程,不能用它来做耗时的请求或者动作
         可以在服务中开一个线程,在线程中做耗时操作
类型:
        1.本地服务(Local Service)
          应用程序内部
           startService  stopService stopSelf stopSelfResult
           bindService  unbindService
         2.远程服务(Remote Service)
             Android系统内部程序之间
             定义IBinder接口
Start 方式特点
          1.服务跟启动源没有任何联系
          2.无法得到服务对象
Bind  方式特点
          1.通过Ibinder接口实例,返回一个ServiceConnection对象给启动源
          2.通过ServiceConnection对象的相关方法可以得到Service对象

3.下面小编将通过一个demo讲述Service:

&实现service的步骤:1.创建一个类继承Service,完成必要的方法;2.在AndroidMinifast文件中进行注册 3. 调用

在此之前小编将讲述一个通过startService启动Servie

package com.demo.internet.musicapp;

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

/**
 * Created by monster on 2015/7/2.
 * 通过Start方式启动服务,这种服务的特点:
 *      1.服务跟启动源没有任何联系
 *      2.无法得到服务对象
 */
public class MusicService extends Service {

    @Override
    public void onCreate() {
        Log.i("info", "Service--onCreate()");
        super.onCreate();
    }

    @Override
    public IBinder onBind(Intent intent) {
        Log.i("info", "Service--onBind()");
        return null;
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.i("info", "Service--onStartCommand()");
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public void onDestroy() {
        Log.i("info", "Service--onDestroy()");
        super.onDestroy();
    }
}

调用:

intent1 =new Intent(MainActivity.this, MyStartService.class);
startService(intent1);

startActivity

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下面小编通过使用bindService方式来实现播放音乐的demo

①.布局不予讲述

②.创建BindMusicService.java 继承Service ,并且进行注册

package com.demo.internet.musicapp;

import android.app.Service;
import android.content.Intent;
import android.content.ServiceConnection;
import android.media.MediaPlayer;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;

/**
 * Created by monster on 2015/7/2.
 * 方式特点:
 * 1.通过Ibinder接口实例,返回一个ServiceConnection对象给启动源
 * 2.通过ServiceConnection对象的相关方法可以得到Service对象
 */
public class BindMusicService extends Service {
    private MediaPlayer mPlayer;  //声明一个mediaPlayer对象
    @Override
    public IBinder onBind(Intent intent) {
        Log.i("info", "BindService--onBind()");
        return new MyBinder();
    }

    @Override
    public void unbindService(ServiceConnection conn) {
        Log.i("info", "BindService--unbindService()");
        super.unbindService(conn);
    }

    @Override
    public void onCreate() {
        Log.i("info", "BindService--onCreate()");
        super.onCreate();
        mPlayer=MediaPlayer.create(getApplicationContext(),R.raw.meizu_music); //实例化对象
        //设置可以重复播放
        mPlayer.setLooping(true);
    }

    @Override
    public void onDestroy() {
        Log.i("info", "BindService--onDestroy()");
        super.onDestroy();
        mPlayer.stop();
    }
    //必须通过继承Binder的方式才可以获得binderService服务
    public class MyBinder extends Binder{
        public BindMusicService getService(){
            return BindMusicService.this;
        }
    }
    public void Play(){
        Log.i("info", "播放");
        mPlayer.start();
    }
    public void Pause(){
        Log.i("info", "暂停");
        mPlayer.pause();
    }

}

③. 在MainActivity中创建ServiceConnection接口并且实现未实现的方法,然后创建BindMusicService的声明,调用的时候bindService方法进行调用

package com.demo.internet.musicapp;

import android.app.Activity;
import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;


public class MainActivity extends Activity implements View.OnClickListener{
    private Button btn_start,btn_stop,bind_btn_start,bind_btn_stop,bind_btn_play,bind_btn_pause;
    Intent intent1;
    Intent intent2;
    BindMusicService service;
    ServiceConnection con=new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder binder) {
            //当服务跟启动源连接的时候 会自动回调
            service=((BindMusicService.MyBinder)binder).getService();
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
            //当服务跟启动源断开的时候 会自动回调
        }
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
    }

    private void initView() {
        btn_start= (Button) findViewById(R.id.btn_start);
        btn_stop= (Button) findViewById(R.id.btn_stop);
        bind_btn_start= (Button) findViewById(R.id.bind_btn_start);
        bind_btn_stop= (Button) findViewById(R.id.bind_btn_stop);
        bind_btn_play= (Button) findViewById(R.id.bind_btn_play);
        bind_btn_pause= (Button) findViewById(R.id.bind_btn_pause);
        //绑定监听事件
        btn_start.setOnClickListener(this);
        btn_stop.setOnClickListener(this);
        bind_btn_start.setOnClickListener(this);
        bind_btn_stop.setOnClickListener(this);
        bind_btn_play.setOnClickListener(this);
        bind_btn_pause.setOnClickListener(this);
    }


    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.btn_start:
                //intent1=new Intent(MainActivity.this,MusicService.class);
                //startService(intent1);
                break;
            case R.id.btn_stop:
                //stopService(intent1);
                break;

            case R.id.bind_btn_start:
                intent2=new Intent(MainActivity.this,BindMusicService.class);
                bindService(intent2,con,BIND_AUTO_CREATE);//绑定服务
                break;
            case R.id.bind_btn_play:
                service.Play();
                break;
            case R.id.bind_btn_pause:
                service.Pause();
                break;
            case R.id.bind_btn_stop:
                unbindService(con);//解除绑定服务
                break;
        }
    }
}

bindService

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4.效果图演示:

musicApp

5.源码分享:

https://git.coding.net/monsterLin/MusicAppService.git

posted @ 2015-07-02 11:36  monsterLin  阅读(737)  评论(0编辑  收藏  举报
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