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service(服务)，后台运行，无界面，只有逻辑代码。

用处非常大，可以执行后台的一些数据操作，比如：更新、读取消息、或者最新动态等等。

要实现service肯定得有一个class，有2种方法创建本地服务，一种就是startService另外一种就是bindService。这两种的区别就是前者不能与Activity通信，而后者可以；这样当然是选择bindService啦。

startService：

它的生命周期是：onCreate()->onStartCommand()->onDestroy()

bindService:

生命周期:onCreate()->onBind()->onUnbind()->onDestroy()

startService的启动与停止方法就是 :startService、stopService；

bindService的启动与停止方法是 :bindService(intent,conn, Service.BIND_AUTO_CREATE); unbindService(conn);//解除

其中conn是ServiceConnection对象,并且要实现对象中的onServiceConnected、onServiceDisconnected两种方法，其中onServiceConnected可获得服务内置的业务对象数据。

以下是Activity.class类的源代码：

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "SERVICELOG";
    ServiceOne.newBinder binder;//服务类的newBinder对象,用于处理业务

 //实现ServiceConnection对象中的onServiceConnected、onServiceDisconnected两种方法
 private ServiceConnection conn = new ServiceConnection() {
     @Override
     public void onServiceConnected(ComponentName name, IBinder service) {
       Log.i(TAG,"onServiceConnected");
       binder = (ServiceOne.newBinder)service;//获得业务对象

   }

   @Override
   public void onServiceDisconnected(ComponentName name) {
       Log.i(TAG,"onServiceDisconnected");
   }
 };

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show();
        }
    });

    init(this);
}


public void init(Context mContext){
    final Intent intent = new Intent();
    intent.setAction("com.test.servicetest.TEST_SERVICE");
    Button start,stop;
    start = (Button)findViewById(R.id.start);
    stop = (Button)findViewById(R.id.stop);

    start.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            //startService(intent);
            bindService(intent,conn, Service.BIND_AUTO_CREATE);//绑定服务
           
            //实例化一个时钟
            Timer timer = new Timer();

            //每10秒从binder对象读取数据一次
            timer.schedule(new TimerTask() {
                @Override
                public void run() {
                    Log.i(TAG, binder.getCon() + "");
                }
            },5000,10000);
        }
    });

    stop.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
           // stopService(intent);
            unbindService(conn);
            Log.i("TAG","stop");
        }
    });


}

//服务类ServiceOne.class源代码

package com.test.servicetest;

import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.support.annotation.Nullable;
import android.util.Log;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Timer;
import java.util.TimerTask;

/**
 * Created by Alan on 2016/05/24 0024.
 */
public class ServiceOne extends Service {
    private static final String TAG = "Service";
    private boolean quit = false;
    public void onCreate() {
        super.onCreate();
        Log.i(TAG, "OnCreate");
        new Thread(new Runnable() {
            @Override
            public void run() {
                while (!quit){
                    try {
                        Thread.sleep(1000);

                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    count++;
                    Log.i(TAG,""+count);
                }
            }
        }).start();

    }

    public int onStartCommand(Intent intent, int flags, int startId) {

        Log.i(TAG, "onStartCommand");
        Timer timer = new Timer();
        timer.schedule(new getMsg(getApplicationContext(), new getMsg.Callback() {
            @Override
            public void onResquest(String res) {
                Log.i(TAG, res);
            }
        }), 5000, 10000);

        return START_STICKY;
    }

    public void onDestroy() {
        super.onDestroy();
        this.quit = true;
        Log.i(TAG, "onDestroy");
    }


    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        Log.i(TAG, "onBind");

        return new newBinder();
    }

    public boolean onUnBind(Intent intent) {
        Log.i(TAG, "onUnBind");

        return true;
    }

    private int count = 0;
    //业务处理对象
    public class newBinder extends Binder{
        public int getCon(){
            return count++;
        }
       
       public String getString(){return count+"";}
    }
}

class getMsg extends TimerTask{

    private Context mContext;
    private Callback callback;

    public getMsg(Context ctx,Callback cb){
        mContext = ctx;
        callback = cb;

    }

    interface Callback{
        void onResquest(String res);
    }
    @Override
    public void run() {
        try {
            URL url = new URL("http://192.168.1.205/1.php");
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();

            InputStreamReader isr = new InputStreamReader(conn.getInputStream());
            BufferedReader reader = new BufferedReader(isr);

            String str,str2 = "";

            while ((str = reader.readLine()) != null){
                str2 += str+"\t\n";
            }



            isr.close();
            reader.close();
            conn.disconnect();
            Log.i("RUN", str2);

            //回调数据
            callback.onResquest(str2);
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}

源代码下载链接：http://pan.baidu.com/s/1nuFoXcd 密码：0k2j