java - 如何安排任务以使其在android中的任何条件下执行

Question

我正在开发一个需要在某些时间运行一些任务的 Android 项目。要执行的任务由用户选择以及需要执行的时间。我曾尝试使用 BroadcastReceiver 和 AlarmManager 来执行任务。但问题是 - 应用关闭时任务停止执行。下面是我的 BroadcastReceiver 和 AlarmManager 类代码。

public class AlarmReceiver extends BroadcastReceiver {

    private static final String TAG = "AlarmReceiver";

    @Override
    public void onReceive(Context context, Intent intent) {
        Log.d(TAG, "onReceive: Alarm received");

        // perform the task here using the values received by Intent
    }
}

我使用 AlarmManager 将此 AlarmReceiver 称为:

    Intent alarmIntent = new Intent(this, AlarmReceiver.class);
    alarmIntent.putExtra("foo", foo);
    alarmIntent.putExtra("bar", bar);
    PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0, alarmIntent, 0);
    AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
    alarmManager.set(AlarmManager.RTC_WAKEUP, date.getTime(), pendingIntent);

其中 date.getTime() 是执行任务的时间。

一切正常。但是我想要一个解决方案，即使应用被强行关闭也能使这项工作正常进行。我还希望该解决方案能够一个接一个甚至第二天执行多个此类任务。 如果可能

注意:我想过使用 Service 类来完成此操作，但不知道如何编写 Service 类。

Answer 1

我认为强制关闭不会让任务继续工作。但是，您可以在系统事件上注册 BroadcastReceiver，让应用程序恢复运行(例如 android.intent.action.BOOT_COMPLETED 和 QUICKBOOT_POWERON)

对于任务，您真的应该查看 WorkManager 库。

参见:https://developer.android.com/reference/androidx/work/package-summary和 https://developer.android.com/topic/libraries/architecture/workmanager它为你监听系统事件做了很多工作。它为重复性和单一任务提供 PeriodicWorkRequest 和 OneTimeWorkRequest。

最新库:androidx.work:work-runtime:2.2.0

import androidx.work.Constraints
import androidx.work.ExistingPeriodicWorkPolicy.REPLACE
import androidx.work.PeriodicWorkRequest
import androidx.work.WorkManager

    private fun startTask(interval: Int) {
        val flexInterval = when {
            interval > 200 -> 30L
            interval > 59 -> 15L
            else -> 5L
        }
        val constraints = Constraints.Builder().setRequiresBatteryNotLow(true).build()

        val fileFinderWork = PeriodicWorkRequest.Builder(
            FileFindWorker::class.java,
            interval.toLong(), TimeUnit.MINUTES,
            flexInterval, TimeUnit.MINUTES
        ).setConstraints(constraints).addTag(WORK_TAG).build()

        Logger.e("Enqueueing file finder worker ($interval min.)")

        val manager: WorkManager = WorkManager.getInstance(ctx)
        manager.enqueueUniquePeriodicWork(WORK_NAME, REPLACE, fileFinderWork)
   }

或者在 Java 中

import androidx.work.Constraints;
import androidx.work.ExistingPeriodicWorkPolicy;
import androidx.work.OneTimeWorkRequest;
import androidx.work.PeriodicWorkRequest;
import androidx.work.WorkManager;

    private UUID startTask() {
        int interval = 99 /* Just a value from configuration */;
        TimeUnit unit;
        int flexInterval;

        if (interval % 60 == 0) {
            interval = interval / 60;
            unit = TimeUnit.HOURS;
        } else {
            unit = TimeUnit.MINUTES;
        }

        if (interval >= 240) {
            flexInterval = 30;
        } else if (interval >= 60) {
            flexInterval = 15;
        } else {
            flexInterval = 5;
        }

        final Constraints constraints = new Constraints.Builder()
                .setRequiresBatteryNotLow(true)
                .build();

        final PeriodicWorkRequest fileFinderWork = new PeriodicWorkRequest.Builder(
                FileFindWorker.class, interval, unit, flexInterval, TimeUnit.MINUTES)
                .setConstraints(constraints)
                .addTag(WORK_TAG)
                .build();

        lastPeriodicUuid = fileFinderWork.getId();

        WorkManager manager = WorkManager.getInstance(ctx)
        manager.enqueueUniquePeriodicWork(WORK_NAME, ExistingPeriodicWorkPolicy.REPLACE, fileFinderWork);

        return fileFinderWork.getId();
    }