并行执行多个 AsyncTask [英] Executing Multiple AsyncTask's Parallely

问题描述

我使用的是 Android SDK 4.0.3 API15，我想并行运行多个 AsyncTask.我从网络服务器获取我的数据并实时动画(10 fps).但是根据用户操作，我还需要向 Web 服务器发送一些数据.发生这种情况时，我的动画会暂停一小段时间(发送数据进入队列并获取数据等待它完成)，因此我无法捕捉实时.

I'm using Android SDK 4.0.3 API15 and I want to run multiple AsyncTasks parallely. I'm getting my data from web server and animating(10 fps) it real-time. But depending on user operations I need to send some data to web server also. When this occurs my animation pauses for a short time (sending data gets into queue and getting data waits it to finish ) and therefore I can't catch the real-time.

这个 answer 很好解释，但我无法让它发挥作用.所以任何帮助将不胜感激.

This answer is quite explaining but I couldn't make it work. So any help will be very appreciated.

我想我需要使用这个函数来实现:

I think I need to use this function to achieve that:

AsyncTask.executeOnExecutor(Executor exec, Params... params)

但是我无法将执行程序作为参数传递，也无法实例化执行程序.这是我的 AsyncTask 类:

But I can't pass an executor as a parameter and I can't instantiate an executor. This is my AsyncTask class:

public class GetPlayers extends AsyncTask<String, Void, String> {
    @Override
    protected String doInBackground(String... urls) {

        Thread.currentThread().setPriority(Thread.MAX_PRIORITY);

        rawData="";
        for (String url : urls) {
            DefaultHttpClient client = new DefaultHttpClient();
            HttpGet httpGet = new HttpGet(url);
            try {
                HttpResponse execute = client.execute(httpGet);
                InputStream content = execute.getEntity().getContent();

                BufferedReader buffer = new BufferedReader(new InputStreamReader(content));
                if((rawData = buffer.readLine()) == null){
                    rawData = "error";
                }

            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return rawData; 
    }

    @Override
    protected void onPostExecute(String result) {
        manipulate();
    }
}

我是这样执行的:

GetPlayers task = new GetPlayers();
requestString = "web adress is here...";
task.execute(new String[] { requestString });

推荐答案

我就是这样做的:

if( Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB ) {
    new MyAsyncTask().executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
} else {
    new MyAsyncTask().execute();
}

其中 MyAsyncTask 是常规的 AsyncTask 子类.或者你可以把这一切都包装在辅助类中:

where MyAsyncTask is regular AsyncTask subclass. Or you can wrap this all in helper class:

class TaskHelper {

    public static <P, T extends AsyncTask<P, ?, ?>> void execute(T task) {
        execute(task, (P[]) null);
    }

    @SuppressLint("NewApi")
    public static <P, T extends AsyncTask<P, ?, ?>> void execute(T task, P... params) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
            task.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, params);
        } else {
            task.execute(params);
        }
    }
}

然后就这样做:

TaskHelper.execute( new MyTask() );

或

TaskHelper.execute( new MyTask(), args );

或

TaskHelper.execute( new MyTask(constructorParams), args );

这篇关于并行执行多个 AsyncTask的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！