AsyncTask demo

  为了解决这个问题，Android 1.5提供了一个工具类：AsyncTask，它使创建需要与用户界面交互的长时间运行的任务变得更简单。相对来说AsyncTask更轻量级一些，适用于简单的异步处理，不需要借助线程和Handler即可实现。 
AsyncTask是抽象类.AsyncTask定义了三种泛型类型 Params，Progress和Result。 
　　Params 启动任务执行的输入参数，比如HTTP请求的URL。 
　　Progress 后台任务执行的百分比。 

　　Result 后台执行任务最终返回的结果，比如String。 

package com.example.aynctaskpro;
 
import android.annotation.SuppressLint;
import android.os.AsyncTask;
import android.util.Log;
 
public class MyTask extends AsyncTask<String, Integer, String> {
 
	@Override
	protected String doInBackground(String... params) {
		// TODO Auto-generated method stub
		Log.d("mytask", "doInBackground params = "+params[0]+" len="+params.length);
		try {
			Thread.sleep(1000);
			publishProgress(new Integer[]{1});
			Thread.sleep(1000);
			publishProgress(new Integer[]{2});
			Thread.sleep(1000);
			publishProgress(new Integer[]{3});
			Thread.sleep(1000);
			publishProgress(new Integer[]{4});
			Thread.sleep(1000);
			publishProgress(new Integer[]{5});
		} catch (InterruptedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return "fuck";
	}
 
	@Override
	protected void onCancelled() {
		// TODO Auto-generated method stub
		Log.d("mytask", "onCancelled");
		super.onCancelled();
	}
 
	@SuppressLint("NewApi")
	@Override
	protected void onCancelled(String result) {
		// TODO Auto-generated method stub
		Log.d("mytask", "onCancelled result="+result);
		super.onCancelled(result);
	}
 
	@Override
	protected void onPostExecute(String result) {
		// TODO Auto-generated method stub
		Log.d("mytask", "onPostExecute result="+result);
		super.onPostExecute(result);
	}
 
	@Override
	protected void onPreExecute() {
		// TODO Auto-generated method stub
		Log.d("mytask", "onPreExecute");
		super.onPreExecute();
	}
 
	@Override
	protected void onProgressUpdate(Integer... values) {
		// TODO Auto-generated method stub
		Log.d("mytask", "onProgressUpdate value="+values[0]+" len="+values.length);
		super.onProgressUpdate(values);
	}
 
 
 
}

package com.example.aynctaskpro;
 
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
 
public class MainActivity extends Activity {
 
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		final MyTask task = new MyTask();
		task.execute("address");
//		Handler h = new Handler();
//		h.postDelayed(new Runnable(){
//
//			@Override
//			public void run() {
//				// TODO Auto-generated method stub
//				Log.d("mytask", "cancel="+task.cancel(false));
//			}
//			
//		}, 3000);
	}
 
 
}

03-05 11:24:38.508: D/mytask(22628): onPreExecute
03-05 11:24:38.508: D/mytask(22628): doInBackground params = address len=1
03-05 11:24:39.508: D/mytask(22628): onProgressUpdate value=1 len=1
03-05 11:24:40.508: D/mytask(22628): onProgressUpdate value=2 len=1
03-05 11:24:41.518: D/mytask(22628): onProgressUpdate value=3 len=1
03-05 11:24:42.518: D/mytask(22628): onProgressUpdate value=4 len=1
03-05 11:24:43.518: D/mytask(22628): onProgressUpdate value=5 len=1
03-05 11:24:43.518: D/mytask(22628): onPostExecute result=fuck