Service服务

package com.example.administrator.myapplication.service;

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

import com.example.administrator.myapplication.R;

public class MyService extends Service {
    MediaPlayer mediaPlayer;//媒体播放类
    public MyService() {
    }

    //自定义Binder类用于获取Service对象
    public class MyBinder extends Binder {
        public MyService getService(){
            return MyService.this;
        }
    }
    @Override
    public void onCreate() {
        super.onCreate();
        mediaPlayer = MediaPlayer.create(this, R.raw.dawang);
    }

    //绑定类
    //必须实现，Ibinder返回值,包含了service与Activity的连接状态给Activity
    @Override
    public IBinder onBind(Intent intent) {
        // throw new UnsupportedOperationException("Not yet implemented");
        mediaPlayer.start();
        return new MyBinder();
    }

    @Override
    public boolean onUnbind(Intent intent) {
        mediaPlayer.stop();
        return super.onUnbind(intent);
    }

    //start类的
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        mediaPlayer.start();
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        mediaPlayer.stop();
    }
}

Activity

package com.example.administrator.myapplication.activity;

import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;

import com.example.administrator.myapplication.R;
import com.example.administrator.myapplication.service.MyService;

public class MusicActivity extends AppCompatActivity {
    Button bindService;
    Button unBindService;
    Button startService;
    Button stopService;
    MyService musicService;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_music);
        bindService = (Button) findViewById(R.id.bindService);
        unBindService = (Button) findViewById(R.id.unBindService);
        startService = (Button) findViewById(R.id.startService);
        stopService = (Button) findViewById(R.id.stopService);
        /*绑定服务 */
        bindService.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MusicActivity.this,MyService.class);
                bindService(intent,connection, Context.BIND_AUTO_CREATE);
            }
        });
        /*解绑服务*/
        unBindService.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //服务不为空时
                if (musicService != null){
                    unbindService(connection);
                    musicService = null;
                }
            }
        });
        /*启动服务*/
        startService.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MusicActivity.this,MyService.class);
                startService(intent);
            }
        });
        /*停止服务*/
        stopService.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MusicActivity.this,MyService.class);
                stopService(intent);
            }
        });
    }
    /*ServiceConnection是一个接口，该接口用于监听服务与启动源之间的链接与断开状态*/
    ServiceConnection connection = new ServiceConnection() {
        /*当服务与启动源绑定时调用*/
        /**
         * 在这里还涉及到IBinder，当启动源和服务成功链接后，可以获取到IBinder对象，
         * 通过IBinder对象，启动源与服务可以完成通信。
         * 在实际开发中通常采用继承Binder（实现了IBinder接口）来实现自己IBinder对象。
         */
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            musicService = ((MyService.MyBinder)service).getService();
        }
        /*当程序因异常而断开服务与启动源之间链接时调用*/
        @Override
        public void onServiceDisconnected(ComponentName name) {

        }

    };
}