service详解

1.Context.startService()方式启动

①Context.startService()方式的生命周期： 启动时，startService –> onCreate() –> onStart()停止时，stopService –> onDestroy()如果调用者直接退出而没有停止Service，则Service 会一直在后台运行 Context.startService()方法启动服务，在服务未被创建时，系统会先调用服务的onCreate()方法，接着调用onStart()方法。如果调用startService()方法前服务已经被创建，多次调用startService()方法并不会导致多次创建服务，但会导致多次调用onStart()方法。采用startService()方法启动的服务，只能调用Context.stopService()方法结束服务，服务结束时会调用onDestroy()方法附代码

2.Context.bindService()方式启动：①Context.bindService()方式的生命周期： 绑定时,bindService -> onCreate() –> onBind()调用者退出了，即解绑定时,Srevice就会unbindService –>onUnbind() –> onDestory()Context.bindService()方式启动 Service的方法：绑定Service需要三个参数：bindService(intent,
conn, Service.BIND_AUTO_CREATE);第一个：Intent对象第二个：ServiceConnection对象，创建该对象要实现它的onServiceConnected()和 onServiceDisconnected()来判断连接成功或者是断开连接第三个：如何创建Service，一般指定绑定的时候自动创建附代码

[java] view
plaincopy

package com.dada.test;

import android.app.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.util.Log;

import android.view.View;

import android.widget.Button;

import com.dada.test.BindService.MyBinder;

public class TestActivity extends Activity {

private boolean flag;

private static final String TAG = "TestActivity";

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

Button btnStart = (Button) findViewById(R.id.btnStart);

Button btnStop = (Button) findViewById(R.id.btnStop);

btnStart.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

//启动service 方式2

bindService();

}

});

btnStop.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

//停止service 方式2

unBindService();

}

});

}

//启动service 方式2

//

private void bindService(){

Intent intent = new Intent(TestActivity.this,BindService.class);

Log.i(TAG, "bindService()");

bindService(intent, conn, Context.BIND_AUTO_CREATE);

}

private void unBindService(){

Log.i(TAG, "unBindService() start....");

if(flag == true){

Log.i(TAG, "unBindService() flag");

unbindService(conn);

flag = false;

}

}

private ServiceConnection conn = new ServiceConnection() {

@Override

public void onServiceDisconnected(ComponentName name) {

// TODO Auto-generated method stub

Log.i(TAG, "onServiceDisconnected()");

}

@Override

public void onServiceConnected(ComponentName name, IBinder service) {

// TODO Auto-generated method stub

Log.i(TAG, "onServiceConnected()");

MyBinder binder = (MyBinder)service;

BindService bindService = binder.getService1();

bindService.MyMethod();

flag = true;

}

};

}

service

[java] view
plaincopy

package com.dada.test;

import android.app.Service;

import android.content.Intent;

import android.os.Binder;

import android.os.IBinder;

import android.util.Log;

public class BindService extends Service {

private static final String TAG = "BindService";

private MyBinder myBinder = new MyBinder();

public void MyMethod(){

Log.i(TAG, "BindService-->MyMethod()");

}

@Override

public IBinder onBind(Intent intent) {

Log.i(TAG, "BindService-->onBind()");

return myBinder;

}

public class MyBinder extends Binder{

public BindService getService1(){

return BindService.this;

}

}

@Override

public void onCreate() {

Log.i(TAG, "BindService-->onCreate()");

super.onCreate();

}

@Override

public void onStart(Intent intent, int startId) {

Log.i(TAG, "BindService-->onStart()");

super.onStart(intent, startId);

}

@Override

public void onDestroy() {

Log.i(TAG, "BindService-->onDestroy()");

super.onDestroy();

}

@Override

public boolean onUnbind(Intent intent) {

Log.i(TAG, "BindService-->onUnbind()");

return super.onUnbind(intent);

}

}

运行日志

点击启动



点击停止



没有打出onServiceDisconnected的日志的原因：
注：SDK上是这么说的：This is called when the connection with the service has been

unexpectedly disconnected -- that is, its process crashed. Because it is running in our same

process, we should never see this happen.

所以说，只有在service因异常而断开连接的时候，这个方法才会用到

其他

由于Service 的onStart()方法只有在startService()启动Service的情况下才调用，故使用onStart()的时候要注意这点。

与 Service 通信并且让它持续运行

如果我们想保持和 Service 的通信，又不想让 Service 随着 Activity 退出而退出呢？你可以先 startService() 然后再 bindService() 。当你不需要绑定的时候就执行 unbindService() 方法，执行这个方法只会触发 Service 的 onUnbind() 而不会把这个 Service 销毁。这样就可以既保持和
Service 的通信，也不会随着 Activity 销毁而销毁了。