线程在Android的处理长时间运行的进程 [英] Threading in Android to process long running processes

问题描述

好吧，这里是我的问题。我想学习的AsyncTask，线程和处理程序处理长时间运行的任务。我用Android的烹饪书和新波士顿Android的教程，但我不能使它发挥作用。

Ok, here is my problem. I want to learn AsyncTask, Threading and Handler to process long running tasks. I used Android Cook Book and New Boston Android tutorial, but I can't make it work.

我需要改变进度条消息。这是不适合的项目，而是要学习线程。线程是真的难受。所以，如果您有任何教程或指南，了解线程，请让我知道。

I need to change the progress bar message. This is not for project, but to learn threading. Threading is really hard for me. So if you have any tutorial or guide to understand threading please let me know.

同时，我试过处理程序类，但没有奏效。因此，我试过的AsyncTask。但它也不行。

Meanwhile I tried Handler class, but it didn't work. So I tried AsyncTask. But it does not work either.

下面是我的code。

package com.example.androidpopup;

import android.app.Activity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {

    Button click_btn;
    ProgressDialog dialog;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        click_btn = (Button) findViewById(R.id.button1);

        click_btn.setOnClickListener(new OnClickListener() {

            public void onClick(View arg0) {
                dialog = ProgressDialog.show(MainActivity.this, "",
                        "Recording...", true);
                dialog.setCancelable(true);
                Thread thread = new Thread(){
                    public void run(){
                        try{
                            sleep(2000);
                            new UpdateUI().execute("testing");
                        }catch(InterruptedException e){
                            e.printStackTrace();
                        }
                    }
                };
            }
        });
    }

    public class UpdateUI extends AsyncTask<String, Integer, String>{

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

        protected void onPreExecute(String f){
            //example of setting up something
            f = "whatever";
        }

        protected void onProgressUpdate(Integer...progress){

        }

        protected void onPostExecute(String result){
            dialog.setMessage(result);
        }

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }
}

如果任何人都可以解释什么是错的我的做法这将是非常有益的。

If anyone can explain what's wrong of my approach it would be really helpful.

感谢您！

推荐答案

为什么要创建一个新的线程只需等待2秒，调用AsyncTask的？我建议你​​删除的主题，通常所说的AsyncTask的和里面放置了Thread.sleep（....）。

Why are you creating a new Thread just to wait 2 seconds to call AsyncTask? I would suggest you to remove that Thread, normally call the AsyncTask and inside it place Thread.sleep(....).

是这样的：

protected void onPreExecute(String f){
     Thread.sleep(2000);
     //example of setting up something
     f = "whatever";
}

PS：为了运行一个线程，你需要调用thread.start。 ;）

PS: in order to run a Thread, you need to call thread.start. ;)

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