android开发：IntentService和前台Service

本文链接： https://blog.csdn.net/qq_39027256/article/details/102670026

一、Service 是长期运行在后台的应用程序组件。默认情况下是和主线程绑定的，所以当我们在onStartCommand方法进行一些耗时操作时容易发生异常，所以android提供了IntentService给我们，它默认会开启一个新的线程执行我们的任务，当任务执行完毕后会主动关闭service.

实现方式：

1.继承IntentService

2.重写它的onHandleIntent方法

3.添加一个构造函数返回service名

/**
 * @Author: david.lvfujiang
 * @Date: 2019/10/21
 * @Describe:
 */
public class MyIntentService extends IntentService {

    public MyIntentService() {
        super("MyIntentService");
    }

    @Override
    protected void onHandleIntent(@Nullable Intent intent) {
        try {
            Thread.sleep(100000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onStart(@Nullable Intent intent, int startId) {
        super.onStart(intent, startId);
    }

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

    @Override
    public int onStartCommand(@Nullable Intent intent, int flags, int startId) {
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return super.onBind(intent);
    }
}

二、当后台运行很多service时，如果系统出现内存不足则会杀死部分服务，但我有些服务我们不想被杀掉的时候我们可以设置

1. 提高Service的优先级：

2.把service写成系统服务，将不会被回收：

3.将服务改成前台服务foreground service：

前台service实现方式：调用startForeground给service添加一个通知栏

/**
 * @Author: david.lvfujiang
 * @Date: 2019/10/21
 * @Describe:
 */
public class MyService extends Service {
    String serviceName = "MyService";
    Notification notification;
    public String getServiceName() {
        return serviceName;
    }

    @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
    @Override
    public void onCreate() {

        super.onCreate();

    }

    @RequiresApi(api = Build.VERSION_CODES.O)
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.e("哈哈哈", "hahh");
        NotificationManager manager = (NotificationManager) this.getSystemService(Context.NOTIFICATION_SERVICE);
        NotificationCompat.Builder builder;
        //判断是否是8.0Android.O
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            NotificationChannel chan1 = new NotificationChannel("static", "Primary Channel", NotificationManager.IMPORTANCE_HIGH);
            manager.createNotificationChannel(chan1);
            builder = new NotificationCompat.Builder(this, "static");
        } else {
            builder = new NotificationCompat.Builder(this);
        }

        builder.setDefaults(NotificationCompat.DEFAULT_SOUND);//设置通知铃声
         notification = builder.setTicker("您有新的消息")
                .setDefaults(Notification.DEFAULT_ALL)
                .setSmallIcon(R.mipmap.ic_launcher)
                .setWhen(System.currentTimeMillis())
                .setContentTitle("下载")
                .setProgress(100, 0, false)
                .setAutoCancel(true)
                .build();

        startForeground(110, notification);
        return super.onStartCommand(intent, flags, startId);
    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return new MyBinder();
    }

    class MyBinder extends Binder {
        public Service getService() {
            return MyService.this;
        }
    }
}

android开发：IntentService和前台Service

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