Question

when I use AsyncTasks checking in the DDMS, the thread persist in memory as waiting thread after the onPostExecute() method, is that normal?. Here is a simplified Activity that reproduces my problem:

package com.example.async;

import android.app.Activity;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;

public class ASyncTaskExampleActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    new ExampleAsyncTask().execute();
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private class ExampleAsyncTask extends AsyncTask<Void, Void, Void> {

    @Override
    protected Void doInBackground(Void... params) {
        for (int i =0; i<50000;i++){
            int j=i*2;
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        return null;
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    protected void onPostExecute(Void result) {
        Log.d("Test","End onPostExecute");
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Answer 1

AsyncTask使用“校对池”技术。每个阿斯辛卡人你们的任务开始到处;在等待任务的“集合”中有一些单向的read子(或按一定限度创建)。池上的一只read子接着你AsyncTask,执行,然后返回池。之后,这一进程会重复进行,直到问题不再有任务。

这种办法有两个重要特点:

no overhead for creating a thread every time
in case of huge number of tasks system performance degrades gracefully: most of the tasks will wait in the queue and only few of them will be executed at a time; eventually all of them will get executed. Otherwise, if a separate thread was started for each task, the system would likely run out of memory or threads, or tasks will take forever to finish.

你在阿斯辛卡·塔克完成学业后,在DDMS中看到的透镜是池子中的一环。

Answer 2

yep this avoids the overhead of killing and restarting the thread when you submit the next AsyncTask

您第一项任务完成后,将再利用同一线。

Answer 3

这里提供的答复都是正确的。除此以外,该池内的这些透镜的地位将是“wait”。在使用像Okim这样的图书馆时也可以看到这种现象,这些图书馆利用网络业务的连接库。

友情链接