Service

Service是Android系统中的四大组件之一，它是一种长生命周期的，没有可视化界面，运行与后天的一种服务程序。

启动方式：

第一种：

被开启的service通过其他组件调用startService（）被创建。

这种service可以无线运行下去，必须调用stopSelf方法后者其他组件调用stopService()方法停止它。

当service被停止时，系统会销毁它。

第二种 

被绑定的service是当其他组件（一个客户）调用bindservice来创建的。

客户可以通过一个IBinder接口和service进行通信。

客户可以通过unbindservice（）方法来关闭这种链接。

一个service可以同时和多个绑定，当多个客户都解除绑定之后，系统会销毁service。

生命周期：

service整体的生命时间是从onCreate()被调用开始，到onDestroy()方法返回为止。和activity一样，service在onCreate()中进行它的初始化工作，在onDestroy()中释放残留资源。

比如，一个音乐播放service可以在onCreate()中创建播放音乐的线程，在onDestroy()中停止这个线程。

onCreate()和onDestroy()会被所有的service调用，不论service是通过startService()还是bindService()建立。

public void intentServicedown(View view) {
        Intent intent1 = new Intent(this,MyIntentService.class);
        Bundle bundle = new Bundle();
        bundle.putString("url","http://vfx.mtime.cn/Video/2019/03/18/mp4/190318214226685784.mp4");
        bundle.putString("path","/sdcard/Movies/www.mp4");
        intent1.putExtras(bundle);
        startService(intent1);
    }

@Override
    protected void onHandleIntent(Intent intent) {
        Bundle extras = intent.getExtras();
        String url = extras.getString("url");
        String path = extras.getString("path");
        Log.i("---show", "onHandleIntent: "+url+path);
        try {
            URL url1 = new URL(url);
            HttpURLConnection httpURLConnection = (HttpURLConnection) url1.openConnection();
            httpURLConnection.setRequestMethod("GET");
            httpURLConnection.setConnectTimeout(2000);
            httpURLConnection.setReadTimeout(2000);
            httpURLConnection.connect();
            if (httpURLConnection.getResponseCode()==200)
            {
                InputStream inputStream = httpURLConnection.getInputStream();
                int len = 0;
                byte[] buff = new byte[1024];
                FileOutputStream fileOutputStream = new FileOutputStream(new File(path));
                int max = httpURLConnection.getContentLength();
                int progress = 0;
                while ((len = inputStream.read(buff))!= -1)
                {
                    fileOutputStream.write(buff,0,len);
                    progress+=len;
                    sendNotification(max,progress);
                }
                Intent intent1 = new Intent();
                intent1.setAction("com.bw.is");
                sendBroadcast(intent1);
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void sendNotification(int max,int progress){
        RemoteViews remoteViews = new RemoteViews(getPackageName(),R.layout.item);
        remoteViews.setProgressBar(R.id.pro,max,progress,false);
        Notification.Builder builder = new Notification.Builder(this);
        builder.setSmallIcon(R.mipmap.ic_launcher);
        builder.setCustomContentView(remoteViews);
        Notification notification = builder.build();
        startForeground(1,notification);
    }

POST

 public void postintentServicedown2(View view) {
        Intent intent1 = new Intent(this,MyIntentService3.class);
        Bundle bundle = new Bundle();
        bundle.putString("path","http://43.143.146.165:7777/foods/postFoods");
        bundle.putString("paren","pageSize=10&currentPage=1");
        intent1.putExtras(bundle);
        startService(intent1);
    }

@Override
    protected void onHandleIntent(Intent intent) {
        String path = intent.getExtras().getString("path");
        String paren = intent.getExtras().getString("paren");
        try {
            URL url = new URL(path);
            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setReadTimeout(2000);
            httpURLConnection.setConnectTimeout(2000);
            httpURLConnection.setDoOutput(true);
            httpURLConnection.connect();
            OutputStream outputStream = httpURLConnection.getOutputStream();
            outputStream.write(paren.getBytes());
            outputStream.flush();
            if (httpURLConnection.getResponseCode() == 200) {
                InputStream inputStream = httpURLConnection.getInputStream();
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
                String str="";
                StringBuilder stringBuilder = new StringBuilder();
                while ((str=bufferedReader.readLine())!=null)
                {
                    stringBuilder.append(str);
                }
                Log.i("---bb", "onHandleIntent: "+stringBuilder.toString());
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }