android - 插入设备时如何使用 WorkManager 创建作业？

Question

我想创建一个在设备插入时触发的作业，就像 ACTION_POWER_CONNECTED 的广播接收器一样。

这是 worker 类(Class):

public class ChargerWorker extends Worker {

/* Constants */
    private static final String TAG = "ChargerWorker";
    private static final long TRIGGER_AGE = TimeUnit.MINUTES.toMillis(30);       // At least 30 min old.

    @NonNull
    @Override
    public Result doWork() {
        Log.e(TAG, "Power connection worker of Indoor/Outdoor lib.");
        IndoorOutdoorLogger.v(TAG, "Power connection worker of Indoor/Outdoor lib.");
        Context context = getApplicationContext();

        if (Conditions.isBatteryChargingOnAC(context)) {
            IndoorOutdoorLogger.d(context, TAG, "Power plugged and connected to AC.");
            Log.e(TAG, "Power plugged and connected to AC.");

            if (WiFiConnection.isWifiConnected(context) && WiFiConnection.isCurrentNetworkIndoorRecognized(context)) {
                // In this case an "upgrade" to the confidence level is possible.
                // Only run when the last known detection is old enough.
                DetectionResult latestResult = DetectionResult.loadFromCache(context);
                if (!latestResult.isTimestampValid(TRIGGER_AGE)) {
                    IndoorOutdoorLogger.d(context, TAG, "AC power while connected to a recognized WiFi network, and last detection is old enough, starting detection.");
                    IndoorOutdoorClient client = new IndoorOutdoorClient(context, null);
                    client.startShortDetection(Trigger.POWER);
                }
            }
        }
        return Result.SUCCESS;
    } }

这是我在 onCreate() 方法中初始化工作的方式:

Constraints constraints = new Constraints.Builder().setRequiresCharging(true).build();
        OneTimeWorkRequest simpleReuquest = new OneTimeWorkRequest.Builder(ChargerWorker.class)
                .setConstraints(constraints)
                .build();
        WorkManager.getInstance().enqueue(simpleReuquest);

当我第一次将设备连接到适配器时，一切正常。但是，当我断开设备并重试时，我再也没有达到 doWork 功能。 相反，我在 logcat 中看到以下消息:

E/WorkerWrapper: Status for 031e39f1-bc10-4a35-9341-11453fc0ca21 is SUCCEEDED; not doing any work.

是因为我使用了OneTimeWorkRequest吗？如果是这样，我如何安排它在每次设备连接到电源时运行？

Answer 1

这是因为你使用了OnTimeWorkRequest，从它的名字你可以推断出这个请求只有一次有效。一旦被触发，它就不会被再次调用，除非你再次对它进行排队。
问题是 WorkManager 不支持与您的需求相关的任何其他请求或约束。看看this question .

如果你真的想使用这种 WorkManger 和 Requests 的模式，我可以给你一个想法，这取决于人们倾向于为手机充电的事实每次都超过几分钟。

您可以结合使用 2 种类型的 WorkRequests:

• OneTimeWorkRequest 这是您算法的实际逻辑。 将约束设置为仅在充电时。
  一旦触发，该工作人员将在没有任何约束的情况下将 PeriodicWorkRequest 加入队列，并且 "The minimum repeat interval that can be defined is 15 minutes"

• PeriodicWorkRequest 每 15 分钟触发一次，并定期检查手机是否仍在充电。
  worker 第一次检测到设备被拔掉时，它会将上面的 OneTimeWorkRequest 排入队列并自行取消。

这样你就不会检测到设备电源状态的快速变化，但它是自 apps that target the API level 26 or higher can no longer register broadcast receivers for implicit broadcasts in their manifest 以来 Android Oreo(及更高版本)中最好的可能。

检查您的设备是否已插入:

你甚至可以检测它是哪种充电，使用这个代码:

IntentFilter ifilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
Intent batteryStatus = context.registerReceiver(null, ifilter);

// Are we charging / charged?
int status = batteryStatus.getIntExtra(BatteryManager.EXTRA_STATUS, -1);
boolean isCharging = status == BatteryManager.BATTERY_STATUS_CHARGING ||
                 status == BatteryManager.BATTERY_STATUS_FULL;

// How are we charging?
int chargePlug = batteryStatus.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1);
boolean usbCharge = chargePlug == BatteryManager.BATTERY_PLUGGED_USB;
boolean acCharge = chargePlug == BatteryManager.BATTERY_PLUGGED_AC;

taken right from android developer guide

取消WorkRequest:

首先，使用标签构建它:

OneTimeWorkRequest.Builder(MyWorker.class)
            .setConstraints(myConstraints)
            .addTag(tag)
            .build();

然后执行 WorkManager.getInstance().cancelAllWorkByTag(tag)

另一种选择是将一个独特的作品加入队列:

WorkManager.getInstance().enqueueUniquePeriodicWork(
            uniqueWorkName, ExistingPeriodicWorkPolicy.REPLACE, periodicWork);

然后使用 WorkManager.getInstance().cancelUniqueWork(workName) 取消它