Service两套生命周期

onCreate() onStartCommand() onDestroy()
服务与其他组件绑定起来
onCreate() onStartCommand() onBind() onUnbind() onDestroy()

PS技巧：实测发现onBind()和onUnbind()并不一定总是执行，但是serviceConnection却总是执行，所以逻辑操作（绑定的时候执行什么东西）可以放在serviceConnection中！！

package com.example.sj.servicedemo2;

import android.app.Service;
import android.content.ComponentName;
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.Toast;

public class Main2Activity extends AppCompatActivity {
    ComponentName componentName;
    Intent intent = new Intent();
    //做连接
    private ServiceConnection conn=new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            //连接成功
            System.out.println("连接成功....");
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
            //连接断开
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        componentName = new ComponentName(this, "com.example.sj.servicedemo2.MyService2");
        intent.setComponent(componentName);
    }

    public void go1(View view) {
        Toast.makeText(this, "启动了", Toast.LENGTH_SHORT).show();
        startService(intent);
    }

    public void go2(View view) {
        Toast.makeText(this, "终止了", Toast.LENGTH_SHORT).show();
        stopService(intent);

    }

    public void go3(View view) {
        Toast.makeText(this, "绑定了", Toast.LENGTH_SHORT).show();
        /*
        Service.BIND_AUTO_CREATE 绑定自动创建
        0 绑定不自动创建  也会把绑定操作搁置，延迟到创建时再去绑定
         */
        bindService(intent,conn, Service.BIND_AUTO_CREATE);


    }

    public void go4(View view) {
        Toast.makeText(this, "解除绑定了", Toast.LENGTH_SHORT).show();
        unbindService(conn);

    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        unbindService(conn);
//        stopService(intent);
    }
}

package com.example.sj.servicedemo2;

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

public class MyService2 extends Service  {
    public MyService2() {
        System.out.println("MyService2的构造器");
    }

    @Override
    public void onCreate() {
        super.onCreate();
        System.out.println("MyService2.onCreate");
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        System.out.println("MyService2.onStartCommand");
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        System.out.println("MyService2.onDestroy");
    }
    //绑定服务执行的方法
    //不一定每次绑定服务都会执行这个方法
    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
        System.out.println("MyService2.onBind");
        return  new MyBinder();
    }
    //解绑定服务执行的方法
    //不一定每次解绑定服务都会执行这个方法
    @Override
    public boolean onUnbind(Intent intent) {
        System.out.println("MyService2.onUnbind");
        return super.onUnbind(intent);
    }
    //Binder将来会作为我们通信的载体
    private class MyBinder extends  Binder{

    }
}