I am using asyncTasks, to load list elements with images (Just followed android's tutorial of efficiently loading bitmaps)
我正在使用asyncTasks，用图像加载列表元素(按照android的高效加载位图教程)
In DDMS, i can see upto 5 AsyncTasks being running
在DDMS中，我可以看到多达5个异步任务正在运行
Now in addition i have added another AsyncTask, which performs some decoding using MediaCodec class.
此外，我还添加了另一个AsyncTask，它使用MediaCodec类执行一些解码。
Now in DDMS, i still see 5 AsyncTasks, and my image loading aynctask or decoding async task executes, not both of them.
现在在DDMS中，我仍然看到5个asynctask，我的图像加载aynctask或decoding async任务执行，而不是两个。
When decoding is running, if i scroll the list, elements' images are not updated Counterly when i launch new decoding asynctask by calling it's execute method, the decoding doesn't start, but if i scroll the list view now, the images are updated.
当解码正在运行时，如果我滚动列表，那么当我通过调用它的execute方法启动新的解码异步任务时，元素的图像不会被对等地更新，解码不会启动，但是如果我现在滚动列表视图，图像会被更新。
So is AsyncTask is limitted??
那么AsyncTask是有限制的吗?
Even in listAdapter i launch an AsyncTask per getView call. I'd expecting 7 running asyncTasks (if list visible elements are 7, say), but DDMS shows only 5 asynctasks running.
即使在listAdapter中，我也会在每个getView调用中启动一个AsyncTask。我希望有7个正在运行的asyncTasks(如果列表中可见的元素是7个)，但是DDMS只显示5个正在运行的asyncTasks。
Now can someone explain me what's the black magic that i can't spell?
有人能解释一下我不会拼写的黑魔法是什么吗?
1 个解决方案
#1
16
How many AsyncTasks can you run at once?
一次可以运行多少个异步任务?
In most versions of Android, the answer is 128.
在Android的大多数版本中，答案是128。
Why will you generally see exactly 5 AsyncTask threads?
为什么您通常只看到5个AsyncTask线程?
AsyncTask thread management is rather confusing, especially since it has changed a lot since the first Android release.
异步任务线程管理是相当混乱的，特别是自从第一个Android版本以来，它已经发生了很大的变化。
In newer Android versions, 5 threads are create by default, and the ThreadPoolExecutor will attempt to run the AsyncTasks on these 5 threads. If you create more than 5 AsyncTasks, it may either queue them or create new threads (but only up to 128).
在较新的Android版本中，默认创建5个线程，并且ThreadPoolExecutor将尝试在这5个线程上运行AsyncTasks。如果您创建了超过5个异步任务，它可以对它们进行排队或者创建新的线程(但是最多只能创建128个)。
Note that in earlier versions of Android, these limits were differently. I believe that, originally, there was only ever one thread created.
请注意，在早期版本的Android中，这些限制是不同的。我相信，最初只有一个线程被创建。
But all your images should load eventually...
但是你所有的图片最终都应该被加载……
To answer the other part of your question, unless you're loading a lot of images (where a lot means >128), all the images should load, although likely sequentially. If the first 5 load and the rest do not, that might indicate that your doInBackground() function is never finishing or there is something else wrong with the AsyncTask you are using.
要回答问题的另一部分，除非您正在加载大量的图像(其中很多表示>128)，否则所有的图像都应该加载，尽管可能是顺序加载的。如果前5个load而其余的没有加载，这可能表明您的doInBackground()函数没有完成，或者您正在使用的AsyncTask有其他问题。
Resources:
资源:
Here are some helpful resources for learning more about AsyncTask thread management:
这里有一些有用的资源来学习更多关于异步任务线程管理的知识:
AsyncTask线程永远不死
Android AsyncTask threads limits?
Android AsyncTask线程限制呢?
Is there a limit of AsyncTasks to be executed at the same time?
同时执行异步任务有限制吗?
#1
16
How many AsyncTasks can you run at once?
一次可以运行多少个异步任务?
In most versions of Android, the answer is 128.
在Android的大多数版本中，答案是128。
Why will you generally see exactly 5 AsyncTask threads?
为什么您通常只看到5个AsyncTask线程?
AsyncTask thread management is rather confusing, especially since it has changed a lot since the first Android release.
异步任务线程管理是相当混乱的，特别是自从第一个Android版本以来，它已经发生了很大的变化。
In newer Android versions, 5 threads are create by default, and the ThreadPoolExecutor will attempt to run the AsyncTasks on these 5 threads. If you create more than 5 AsyncTasks, it may either queue them or create new threads (but only up to 128).
在较新的Android版本中，默认创建5个线程，并且ThreadPoolExecutor将尝试在这5个线程上运行AsyncTasks。如果您创建了超过5个异步任务，它可以对它们进行排队或者创建新的线程(但是最多只能创建128个)。
Note that in earlier versions of Android, these limits were differently. I believe that, originally, there was only ever one thread created.
请注意，在早期版本的Android中，这些限制是不同的。我相信，最初只有一个线程被创建。
But all your images should load eventually...
但是你所有的图片最终都应该被加载……
To answer the other part of your question, unless you're loading a lot of images (where a lot means >128), all the images should load, although likely sequentially. If the first 5 load and the rest do not, that might indicate that your doInBackground() function is never finishing or there is something else wrong with the AsyncTask you are using.
要回答问题的另一部分，除非您正在加载大量的图像(其中很多表示>128)，否则所有的图像都应该加载，尽管可能是顺序加载的。如果前5个load而其余的没有加载，这可能表明您的doInBackground()函数没有完成，或者您正在使用的AsyncTask有其他问题。
Resources:
资源:
Here are some helpful resources for learning more about AsyncTask thread management:
这里有一些有用的资源来学习更多关于异步任务线程管理的知识:
AsyncTask线程永远不死
Android AsyncTask threads limits?
Android AsyncTask线程限制呢?
Is there a limit of AsyncTasks to be executed at the same time?
同时执行异步任务有限制吗?