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我已经按照Android开发人员的教程使用工作管理器结构在后台运行我的代码,但是当我尝试将我的工作人员排队时它不会运行,我收到以下错误:

2018-10-04 22:25:47.004 28669-28885/app.package.com.debug E/DefaultWorkerFactory: Could not instantiate app.package.com.MyWorker
    java.lang.NoSuchMethodException: <init> []
        at java.lang.Class.getConstructor0(Class.java:2320)
        at java.lang.Class.getDeclaredConstructor(Class.java:2166)
        at androidx.work.DefaultWorkerFactory.createWorker(DefaultWorkerFactory.java:58)
        at androidx.work.impl.WorkerWrapper.runWorker(WorkerWrapper.java:180)
        at androidx.work.impl.WorkerWrapper.run(WorkerWrapper.java:117)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1162)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:636)
        at java.lang.Thread.run(Thread.java:764)
2018-10-04 22:25:47.005 28669-28885/app.package.com.debug E/WorkerWrapper: Could for create Worker app.package.com.MyWorker

我已经看到这个问题可能与worker上的默认构造函数有关但我已经使用了正确的构造函数而不是不推荐使用的默认函数.

我的工人被宣布为:

public class MyWorker extends Worker {

    public MyWorker(@NonNull Context context, @NonNull WorkerParameters workerParams) {
        super(context, workerParams);
    }

    @NonNull
    @Override
    public Result doWork() {
        // Doesn't even get called
    }
}

它就像这样排队:

WorkManager workManager = WorkManager.getInstance();
if (myWorkerRequest == null) …

我想在应用程序启动时从服务器下载某些文件。所以我尝试使用工作管理器，它从我的自定义应用程序类中排队。但是 Worker 类没有被触发，状态只是入队，不会进入运行状态.下面是我的代码：

应用类：

@Override
public void onCreate() {
    Constraints constraints = new Constraints.Builder()
            .setRequiredNetworkType(NetworkType.CONNECTED)
            //.setRequiresStorageNotLow(true)
            //.setRequiresBatteryNotLow(true)
            .build();

    OneTimeWorkRequest request = new OneTimeWorkRequest
            .Builder(MyWorker.class)
            //.setConstraints(constraints)
            //.setInitialDelay(1,TimeUnit.SECONDS)
            .addTag("download")
            .build();

    WorkManager.getInstance(getApplicationContext()).getWorkInfoByIdLiveData(request.getId()).observeForever(new Observer<WorkInfo>() {
        @Override
        public void onChanged(WorkInfo workInfo) {
            if (workInfo == null) {
                Log.d("download", "workInfo == null");
            } else {
                Log.d("download", "workInfo != null: " + workInfo.getState().toString());//This is giving ENQUEUED once..thats it
            }
        }
    });
    WorkManager.getInstance(getApplicationContext()).enqueue(request);
}

我的工人类

public class MyWorker extends Worker {

public MyWorker(@NonNull Context context, @NonNull …