在 background.systemjob.SystemJobService.onCreate 中调用 WorkManagerImpl.getInstance 导致 java.lang.IllegalStateException

Question

我们正在使用以下 WorkManager 库

def work_version = "2.1.0-beta01"
implementation "androidx.work:work-runtime:$work_version"

---

我们的Application 类正在修改如下，以便它可以很好地与WorkManager 一起使用

public class WeNoteApplication extends MultiDexApplication implements DefaultLifecycleObserver, Configuration.Provider {

    private static WeNoteApplication me;

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

        me = this;

        ...
    }

   public static WeNoteApplication instance() {
        return me;
    }

    @NonNull
    @Override
    public Configuration getWorkManagerConfiguration() {
        return new Configuration.Builder()
                .build();
    }
}

---

我们不会在AndroidManifest.xml 中添加任何WorkManager 相关代码。我们完全依赖Default initialization

---

这就是我们构造WorkManager的方式

public static WorkManager getWorkManager() {
    WeNoteApplication weNoteApplication = WeNoteApplication.instance();
    return WorkManager.getInstance(weNoteApplication);
}

上面的函数在 4 个不同的地方被调用

1. Activity
2. Fragment
3. BroadcastReceiver
4. IntentService

---

不过，我们在生产中收到以下崩溃日志。它发生在 Android 7.1、Android 8.1、Android 9（到目前为止）

java.lang.RuntimeException: 
  at android.app.ActivityThread.handleCreateService (ActivityThread.java:3265)
  at android.app.ActivityThread.-wrap5 (ActivityThread.java)
  at android.app.ActivityThread$H.handleMessage (ActivityThread.java:1598)
  at android.os.Handler.dispatchMessage (Handler.java:102)
  at android.os.Looper.loop (Looper.java:241)
  at android.app.ActivityThread.main (ActivityThread.java:6274)
  at java.lang.reflect.Method.invoke (Method.java)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run (ZygoteInit.java:886)
  at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:776)
Caused by: java.lang.IllegalStateException: 
  at androidx.work.impl.WorkManagerImpl.getInstance (WorkManagerImpl.java:142)
  at androidx.work.impl.background.systemjob.SystemJobService.onCreate (SystemJobService.java:53)
  at android.app.ActivityThread.handleCreateService (ActivityThread.java:3255)
  at android.app.ActivityThread.-wrap5 (ActivityThread.java)
  at android.app.ActivityThread$H.handleMessage (ActivityThread.java:1598)
  at android.os.Handler.dispatchMessage (Handler.java:102)
  at android.os.Looper.loop (Looper.java:241)
  at android.app.ActivityThread.main (ActivityThread.java:6274)
  at java.lang.reflect.Method.invoke (Method.java)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run (ZygoteInit.java:886)
  at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:776)

正如您在崩溃中看到的，崩溃源自内部的WorkManager，而不是来自我们的应用程序。

通过查看https://android.googlesource.com/platform/frameworks/support/+/androidx-master-dev/work/workmanager/src/main/java/androidx/work/impl/WorkManagerImpl.java#142

WorkManagerImpl

/**
 * Retrieves the singleton instance of {@link WorkManagerImpl}.
 *
 * @param context A context for on-demand initialization.
 * @return The singleton instance of {@link WorkManagerImpl}
 * @hide
 */
@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
public static @NonNull WorkManagerImpl getInstance(@NonNull Context context) {
    synchronized (sLock) {
        WorkManagerImpl instance = getInstance();
        if (instance == null) {
            Context appContext = context.getApplicationContext();
            if (appContext instanceof Configuration.Provider) {
                initialize(
                        appContext,
                        ((Configuration.Provider) appContext).getWorkManagerConfiguration());
                instance = getInstance(appContext);
            } else {
                throw new IllegalStateException("WorkManager is not initialized properly.  You "
                        + "have explicitly disabled WorkManagerInitializer in your manifest, "
                        + "have not manually called WorkManager#initialize at this point, and "
                        + "your Application does not implement Configuration.Provider.");
            }

IllegalStateException有两种可能

1. appContext 为空。 （怎么可能是空的？）
2. appContext 没有实现Configuration.Provider（但我们已经在WeNoteApplication 中实现了Configuration.Provider？）

要弄清楚上下文是如何从SystemJobService 传递到WorkManagerImpl，我们看一下代码 androidx.work.impl.background.systemjob.SystemJobService.onCreate - https://android.googlesource.com/platform/frameworks/support/+/androidx-master-dev/work/workmanager/src/main/java/androidx/work/impl/background/systemjob/SystemJobService.java#53

系统作业服务

@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
@RequiresApi(WorkManagerImpl.MIN_JOB_SCHEDULER_API_LEVEL)
public class SystemJobService extends JobService implements ExecutionListener {
    private static final String TAG = Logger.tagWithPrefix("SystemJobService");
    private WorkManagerImpl mWorkManagerImpl;
    private final Map<String, JobParameters> mJobParameters = new HashMap<>();
    @Override
    public void onCreate() {
        super.onCreate();
        mWorkManagerImpl = WorkManagerImpl.getInstance(getApplicationContext());

---

乍一看还不错。但是，为什么WorkManagerImpl 无法获得Configuration.Provider，尽管我已经在我的Application 中实现了Configuration.Provider？是因为我用的是MultiDexApplication吗？

---

发现

在 SystemJobService 中，由于 auto-backup 原因，它可以预期 null，并且能够容忍来自 WorkManagerImpl.getInstance 的 null。

@Override
public void onCreate() {
    super.onCreate();
    mWorkManagerImpl = WorkManagerImpl.getInstance(getApplicationContext());
    if (mWorkManagerImpl == null) {
        // This can occur if...
        // 1. The app is performing an auto-backup.  Prior to O, JobScheduler could erroneously
        //    try to send commands to JobService in this state (b/32180780).  Since neither
        //    Application#onCreate nor ContentProviders have run, WorkManager won't be
        //    initialized.  In this case, we should ignore all JobScheduler commands and tell it
        //    to retry.

但是，当前 WorkManagerImpl.getInstance(Context context) 的实现是，它永远不会返回 null 而是抛出 IllegalStateException。

这两个SystemJobService.onCreate逻辑和WorkManagerImpl.getInstance逻辑之间是不是有冲突？

---

问题跟踪器

我将我的观察提交给https://issuetracker.google.com/issues/135858602

Answer 1

这是一个错误。本周晚些时候将在 WorkManager 2.1.0-rc01 中提供修复。