AsyncTask onBackground（） 抛出错误 - 由以下原因引起：java.lang.IllegalStateException：必须在主线程上调用方法 addObserver

问：

今天我打开了我的项目，这个项目已经有大约 6 个月没有更新了，我决定更新所有库以使其与最新的 Android 开发环境保持同步。

在更新了几个库后，我的应用程序在非常简单的 AsyncTask 的 onBackground（） 部分中抛出异常。

这是我的 AsyncTask，非常简单的代码，在后台创建数据库，然后开始一个新活动。

        new AsyncTask() {
              
            @Override
            protected Object doInBackground(Object[] objects) {
                     
                //Creates database while showing a simple loading screen.
                MyDatabase.initalize();
                return null;
            }
    
            @Override
            protected void onPostExecute(Object o) {
                super.onPostExecute(o);

                //When the database has been created, starts a new activity

                if (isInForeground) {
                    Intent intent= new Intent(StartAppActivity.this, GameAppActivity.class);
                    startActivity(intent);
                    finish();
                }
            }
        }.execute();

这是崩溃：

hu.myname.test.app        E  FATAL EXCEPTION: AsyncTask #1
Process: hu.myname.test.app, PID: 15536
java.lang.RuntimeException: An error occurred while executing doInBackground()
    at android.os.AsyncTask$4.done(AsyncTask.java:415)
    at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:383)
    at java.util.concurrent.FutureTask.setException(FutureTask.java:252)
    at java.util.concurrent.FutureTask.run(FutureTask.java:271)
    at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:305)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
    at java.lang.Thread.run(Thread.java:923)
Caused by: java.lang.ExceptionInInitializerError
    at hu.myname.test.game.dbs.lexicon.MyDatabase.initalize(MyDatabase.java:49)
    at hu.myname.test.activity.StartAppActivity$1.doInBackground(StartAppActivity.java:121)
    at android.os.AsyncTask$3.call(AsyncTask.java:394)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:305) 
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167) 
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641) 
    at java.lang.Thread.run(Thread.java:923) 
Caused by: java.lang.IllegalStateException: Method addObserver must be called on the main thread
    at androidx.lifecycle.LifecycleRegistry.enforceMainThreadIfNeeded(LifecycleRegistry.java:317)
    at androidx.lifecycle.LifecycleRegistry.addObserver(LifecycleRegistry.java:172)
    at androidx.fragment.app.Fragment.initLifecycle(Fragment.java:471)
    at androidx.fragment.app.Fragment.<init>(Fragment.java:451)
    at hu.myname.test.fragment.base.BaseFragment.<init>(BaseFragment.java:30)
    at hu.myname.test.fragment.lexicon.base.LexiconAbstractFragment.<init>(LexiconAbstractFragment.java:30)
    at hu.myname.test.fragment.lexicon.TabsLexiconFragment.<init>(TabsLexiconFragment.java:11)
    at hu.myname.test.game.dbs.lexicon.MyDatabase.<clinit>(MyDatabase.java:27)
    at hu.myname.test.game.dbs.lexicon.MyDatabase.runStatic(MyDatabase.java:49) 
    at hu.myname.test.activity.StartAppActivity$1.doInBackground(StartAppActivity.java:121) 
    at android.os.AsyncTask$3.call(AsyncTask.java:394) 
    at java.util.concurrent.FutureTask.run(FutureTask.java:266) 
    at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:305) 
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167) 
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641) 
    at java.lang.Thread.run(Thread.java:923) 

我试图将异步任务更改为不同的后台解决方案，如线程和执行程序，但它抛出了完全相同的错误。

Caused by: java.lang.IllegalStateException: Method addObserver must be called on the main thread

这是怎么回事？我只是更新了一些库，没有编写新代码。我觉得 Android 开发就像站在火车前放下铁轨一样。

有什么见解吗？