当MainThread处于阻塞状态时ANR对话框如何显示(How ANR dialogs shows while MainThread is in Blocked state)

 我正在阅读ANR 。 大多数事情对我来说都有意义，但我不明白如果主线程被阻塞，操作系统如何在同一个进程中创建一个Dialog并将其显示在屏幕上。 从文档： 
 
 
 
 当下列情况之一发生时，您的应用将触发ANR： 

 1.当您的活动处于前台时，您的应用程序在5秒内未响应输入事件或BroadcastReceiver （例如按键或屏幕触摸事件）。 

 2.虽然您没有在前台进行任何活动，但您的BroadcastReceiver尚未在相当长的时间内完成执行。 
 
 
 即主线程与另一个线程处于死锁状态所以操作系统如何设置显示对话框。 因为我认为我们只能从主线程显示对话框。 请纠正我，如果我错了，让我知道ANR对话的过程。 
 任何解释将非常感激。 谢谢 

I am reading ANR. Most of things make sense to me but i can not understand that if Main thread is blocked then How OS create a Dialog in same process and show it on screen . From the Documentation:
 
 
 
An ANR will be triggered for your app when one of the following conditions occur:

 1. While your activity is in the foreground, your app has not responded to an input event or BroadcastReceiver (such as key press or screen touch events) within 5 seconds.

 2. While you do not have an activity in the foreground, your BroadcastReceiver hasn't finished executing within a considerable amount of time.
 
 
i.e The main thread is in a deadlock with another thread So how the OS manage to show a dialog . Cause i think we can only show dialog from a main thread. Please correct me if i am wrong and let me know the process of ANR dialog.
 Any explanation will be really appreciated. Thx

原文：https://stackoverflow.com/questions/49423123