仍然使用同步列表获得并发修改异常

Question

Gretiings，我之前问过这个问题，但即使在更改之后我仍然收到并发修改异常，我已经实现了 synchronizedList 和 synchronized(list) 但异常仍然发生，我没有想法了，可以你给一些建议还有什么可能发生的？谢谢

manager.getMutableList()
        .observe(viewLifecycleOwner, Observer { queueList ->
            Collections.synchronizedList(ArrayList<Object>()).apply {
                this.addAll(queueList)
                synchronized(this) {
                    if (this.isNotEmpty()) {
                        // Do Something
                    } else {
                        // Do other stuff
                    }

                    (recyclerView.adapter as Adapter).run {
                        items = this@apply
                        notifyDataSetChanged()
                        hideLoadingScreen()
                    }
                }
            }
        })

这是异常的痕迹

Fatal Exception: java.util.ConcurrentModificationException
   at java.util.ArrayList$SubList.size(ArrayList.java:1057)
   at java.util.AbstractCollection.toArray(AbstractCollection.java:136)
   at java.util.ArrayList.addAll(ArrayList.java:588)
   at java.util.Collections$SynchronizedCollection.addAll(Collections.java:2089)
   at com.sample.app.ui.Fragment$setObservers$6.onChanged(Fragment.java:382)
   at com.sample.app.ui.Fragment$setObservers$6.onChanged(Fragment.java:89)
   at androidx.lifecycle.LiveData.considerNotify(LiveData.java:131)
   at androidx.lifecycle.LiveData.dispatchingValue(LiveData.java:144)
   at androidx.lifecycle.LiveData$ObserverWrapper.activeStateChanged(LiveData.java:443)
   at androidx.lifecycle.LiveData$LifecycleBoundObserver.onStateChanged(LiveData.java:395)
   at androidx.lifecycle.LifecycleRegistry$ObserverWithState.dispatchEvent(LifecycleRegistry.java:361)
   at androidx.lifecycle.LifecycleRegistry.forwardPass(LifecycleRegistry.java:300)
   at androidx.lifecycle.LifecycleRegistry.sync(LifecycleRegistry.java:339)
   at androidx.lifecycle.LifecycleRegistry.moveToState(LifecycleRegistry.java:145)
   at androidx.lifecycle.LifecycleRegistry.handleLifecycleEvent(LifecycleRegistry.java:131)
   at androidx.fragment.app.FragmentViewLifecycleOwner.handleLifecycleEvent(FragmentViewLifecycleOwner.java:51)
   at androidx.fragment.app.Fragment.performStart(Fragment.java:2737)
   at androidx.fragment.app.FragmentStateManager.start(FragmentStateManager.java:365)
   at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1194)
   at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1356)
   at androidx.fragment.app.FragmentManager.moveFragmentToExpectedState(FragmentManager.java:1434)
   at androidx.fragment.app.BackStackRecord.executeOps(BackStackRecord.java:442)
   at androidx.fragment.app.FragmentManager.executeOps(FragmentManager.java:2169)
   at androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:1992)
   at androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:1947)
   at androidx.fragment.app.FragmentManager.execPendingActions(FragmentManager.java:1849)
   at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:2629)
   at androidx.fragment.app.FragmentManager.dispatchStart(FragmentManager.java:2583)
   at androidx.fragment.app.Fragment.performStart(Fragment.java:2739)
   at androidx.fragment.app.FragmentStateManager.start(FragmentStateManager.java:365)
   at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1194)
   at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1356)
   at androidx.fragment.app.FragmentManager.moveFragmentToExpectedState(FragmentManager.java:1434)
   at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1497)
   at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:2625)
   at androidx.fragment.app.FragmentManager.dispatchStart(FragmentManager.java:2583)
   at androidx.fragment.app.Fragment.performStart(Fragment.java:2739)
   at androidx.fragment.app.FragmentStateManager.start(FragmentStateManager.java:365)
   at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1194)
   at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1356)
   at androidx.fragment.app.FragmentManager.moveFragmentToExpectedState(FragmentManager.java:1434)
   at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1497)
   at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:2625)
   at androidx.fragment.app.FragmentManager.dispatchStart(FragmentManager.java:2583)
   at androidx.fragment.app.FragmentController.dispatchStart(FragmentController.java:258)
   at androidx.fragment.app.FragmentActivity.onStart(FragmentActivity.java:550)
   at androidx.appcompat.app.AppCompatActivity.onStart(AppCompatActivity.java:210)
   at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1419)
   at android.app.Activity.performStart(Activity.java:7479)
   at android.app.ActivityThread.handleStartActivity(ActivityThread.java:3454)
   at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:180)
   at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:165)
   at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:142)
   at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:70)
   at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2199)
   at android.os.Handler.dispatchMessage(Handler.java:112)
   at android.os.Looper.loop(Looper.java:216)
   at android.app.ActivityThread.main(ActivityThread.java:7625)
   at java.lang.reflect.Method.invoke(Method.java)
   at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:524)
   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:987)

Answer 1

在我看来，您正在锁定“this”，这是每次执行的唯一列表。您应该锁定一个共享对象，例如 queueList。