Android WorkManager让app保活

使用WorkManager保活，即使应用被杀掉，也是可以继续执行代码的，目前运行环境是模拟器，具体国内各厂商能否执行，未经过实际测试，就不说了。
我们首先定义Worker类，用来发送通知，然后点击通知可以打开Activity，当然我们也可以做其他的操作。

public class UploadWorker extends Worker {
    public UploadWorker(@NonNull Context context, @NonNull WorkerParameters workerParams) {
        super(context, workerParams);
    }

    @RequiresApi(api = Build.VERSION_CODES.O)
    @NonNull
    @Override
    public Result doWork() {
        Log.e("workmanager","UploadWorker dowork");


        NotificationChannel channel = new NotificationChannel("1","study", NotificationManager.IMPORTANCE_HIGH);
        NotificationManager manager = (NotificationManager) getApplicationContext().getSystemService(Context.NOTIFICATION_SERVICE);
        manager.createNotificationChannel(channel);

        Intent intent = new Intent(getApplicationContext(), WorkManagerTestActivity.class);
        intent.setPackage("com.example.jetpacktest");
        PendingIntent pendingIntent = PendingIntent.getActivity(getApplicationContext(),1,intent,PendingIntent.FLAG_UPDATE_CURRENT);
        Icon icon = Icon.createWithResource(getApplicationContext(),R.mipmap.address);
        Notification.Action action = new Notification.Action.Builder(icon,"学习",pendingIntent)
                .build();
        Notification.Builder notification = new Notification.Builder(getApplicationContext(),"1").setSmallIcon(icon)
                .addAction(action);
        manager.notify(1,notification.build());
        return Result.success();
    }
}

然后在Activity中调用Worker

/**
 * 使用workmanager
 */
public class WorkManagerTestActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_work_manager_test);

        Constraints constraints = new Constraints.Builder()
                .setRequiredNetworkType(NetworkType.NOT_REQUIRED)
                .setRequiresBatteryNotLow(true).build();

        PeriodicWorkRequest request = new PeriodicWorkRequest.Builder(UploadWorker.class,300, TimeUnit.MILLISECONDS)
                .setConstraints(constraints).build();

        OneTimeWorkRequest workRequest1 = new OneTimeWorkRequest.Builder(UploadWorker.class).setConstraints(constraints)
                .setInitialDelay(200,TimeUnit.MILLISECONDS)
                .build();

        OneTimeWorkRequest workRequest2 = new OneTimeWorkRequest.Builder(UploadWorker.class).setConstraints(constraints)
                .setInitialDelay(400,TimeUnit.MILLISECONDS)
                .build();

        OneTimeWorkRequest workRequest3 = new OneTimeWorkRequest.Builder(UploadWorker.class).setConstraints(constraints)
                .setInitialDelay(400,TimeUnit.MILLISECONDS)
                .build();
        WorkManager.getInstance(this).beginWith(workRequest1).then(workRequest2).then(workRequest3).then(workRequest3).enqueue();

        WorkManager.getInstance(this).getWorkInfoByIdLiveData(request.getId())
                .observe(this, new Observer<WorkInfo>() {
                    @Override
                    public void onChanged(WorkInfo workInfo) {
                        Log.e("workmanager","onchanged");
                    }
                });
    }
}

结果图：

11:23:15.691这个时间点时候，app并未被杀掉，这个时间点之后app才被杀掉，杀掉之后，等到了11:38:16.445这个时间，第二个Worker才开始启动，间隔了15min，所以也不是很及时的操作，但是完全是可以复活app的。

经过实际测试，直接杀掉app后，确实是能收到通知，但是存在一个问题，执行的时间是不确定的，关闭app之后，间隔15min才会调用Worker的doWork方法，因此肯定是要间隔一段时间才会重启app。