服务与AsyncTask的 [英] Service and AsyncTask

问题描述

我如何运行，并在AsyncTask的服务，这样，当我做我的工作在服务的UI不会冻结？
今天我实现了一个非常基本的服务：

How can i run and AsyncTask in a Service so that the UI does not freeze when i do my work in a service? Today i implemented a very basic service:

public class ImageSendEmailService extends Service {
    private NotificationManager notificationManager = null;
    private Notification notification = null;

    @Override
    public void onCreate() {
        super.onCreate();

        this.notificationManager = (NotificationManager) this.getSystemService(NOTIFICATION_SERVICE);
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        for (int i = 0; i <= 10; i++) {
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

            String notificationText = String.valueOf((int) (100 * i / 10)) + " %";

            Notification.Builder builder = new Notification.Builder(this);
            builder.setContentTitle("Progress");
            builder.setContentText(notificationText);
            builder.setTicker("Notification!");
            builder.setWhen(System.currentTimeMillis());
            builder.setDefaults(Notification.DEFAULT_SOUND);
            builder.setAutoCancel(true);
            builder.setSmallIcon(R.drawable.ic_launcher);

            this.notification = builder.build();
            this.notificationManager.notify(0, notification);
        }

        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }
}   

可是当我执行用户界面是冻结。

but the ui is freezing while i perform that.

推荐答案

您可以运行的AsyncTask 在服务就像你在一个活动运行或片段。为什么会有什么区别呢？

You can run an AsyncTask in a Service just like you would run it in an Activity or Fragment. Why would there be any difference?

ExampleTask task = new ExampleTask();
task.execute();

但你也可以继承 IntentService 而不是服务！一个 IntentService 自动处理每个意图在一个单独的发。这样，你可以不阻塞UI执行中的服务的工作，你不必应付 AsyncTasks 或主题！

But you can also subclass IntentService instead of Service! An IntentService automatically handles each Intent in a separate Thread. That way you can perform work in the Service without blocking the UI and you don't have to deal with AsyncTasks or Threads!

public class ImageSendEmailService extends IntentService {

    @Override
    protected void onHandleIntent(Intent intent) {
        // Do your work here!
    }
}

您可以找到 IntentService 的 这里 。

You can find the documentation of IntentService here.

顺便说一句：无论你正在尝试与有视频下载（）是一个非常糟糕的主意。切勿使用视频下载（）这样。使用定时或处理程序，而不是！

As an aside: Whatever you are trying to there with Thread.sleep() is a really bad idea. Never use Thread.sleep() like that. Use a Timer or Handler instead!

这篇关于服务与AsyncTask的的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！