从另一个 AsyncTask doInBackground() 启动 AsyncTask [英] Start AsyncTask from another AsyncTask doInBackground()

问题描述

我正在尝试从另一个 AsyncTask doInBackground() 方法开始一个 AsyncTask...

I'm trying to start an AsyncTask from another AsyncTask's doInBackground()-method...

这甚至可能吗?如果是，我怎样才能做到这一点?

Is this even possible? If yes, how can I achieve this?

后期

这个想法是我开始一个异步任务，它会从 Tweeter 获取我的状态......一切都很好，直到这里......但是当我遇到一些特定的推文时，我需要用我的服务器上的一些信息来修改它们，在这里我会进行另一个网络操作，因为我需要等到从我的服务器获取信息，所以我这样做:

The idea is that I start an asynctask that will get me statuses from Tweeter ... Everything ok until here ... But when I encounter some specific tweets I need to modify them with some info from my server, here I will make another network operation, and since I need to wait until I get the info from my server I do:

GetContent getContentServiceAsyncTask = new GetContent(context);
try {
    tweetText = Uri.decode(getContentServiceAsyncTask.execute(
            URL_GET_CONTENT, jsonRequest).get());
} catch (InterruptedException e) {
    Log.e(TAG_DEBUG, "InterruptedException: ", e);
} catch (ExecutionException e) {
    Log.e(TAG_DEBUG, "ExecutionException: ", e);
}

这是从 doInBackground() 方法中已经启动的 AsyncTask 开始的...

This is started from the allready started AsyncTask in doInBackground() method ...

我知道我可以在 AsyncTask 中添加方法并在 doInBackground() 方法中调用它们，但我需要在其他地方使用它们，我从 onPostExecute 开始这些 AsyncTasks ...

I know I can just add the methods in the AsyncTask and just call them in the doInBackground() method, but I need to use them in other places, where I start these AsyncTasks from onPostExecute ...

如果你们认为有一个简单的解决方法，这不会影响我的表现，那就太好了……如果不是，我将制作一些静态方法，我将在我需要的所有 AsyncTasks 中调用这些方法(但这需要我修改很多代码)

If you guys think there is an easy work-around for this, that won't affect my performance, that will be great ... if not I will make some static methods that I will call in all the AsyncTasks I need(but this will require me to modify a lot of my code)

推荐答案

根据下面的帖子，您可以执行 Activity.runOnUiThread() 在主线程上运行 Runnable(从另一个线程).

According to the post below you can do Activity.runOnUiThread() to run a Runnable on the main-Thread (from another thread).

• 在主线程中从另一个线程运行代码

所以理论上你可以这样做:

So theoretically you could do this:

• 运行异步任务
• 在你的 AsyncTask 中执行 Activity.runOnUiThread(Runnable) 并从这个 runnable 内部启动一个新的 AsyncTask

顾名思义Activity.runOnUiThread()在主线程上执行runnable

As the name says Activity.runOnUiThread() executes the runnable on the main-thread

但它有点hacky.

代码应该是这样的:(没有测试)

Code should look something like this: (didnt test)

// first task
    (new AsyncTask<String, String, String>() {

        @Override
        protected String doInBackground(String... params) {
            ParentActitity.this.runOnUiThread(new Runnable() {

                @Override
                public void run() {
                    //second async stared within a asynctask but on the main thread
                    (new AsyncTask<String, String, String>() {

                        @Override
                        protected String doInBackground(String... params) {
                            // TODO Auto-generated method stub
                            return null;
                        }

                    }).execute();

                }
            });
            return null;
        }

    }).execute();

这个嵌套示例不是在生产中使用的好样式，因为(恕我直言)它几乎不可读.

This nested example is not a good style to use in production because (IMHO) its close to unreadable.

附加说明:

Activity.runOnUiThread(Runnable) 不是静态的！这就是为什么我的示例使用 ParentActivity(.this).runOnUiThread(Runnable).

Activity.runOnUiThread(Runnable) is not static! Thats why my example uses ParentActivity(.this).runOnUiThread(Runnable).

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