Android:AysncTask异步加载

以下是链接：

http://blog.csdn.net/abc5382334/article/details/17097633

http://keeponmoving.iteye.com/blog/1515611

http://www.cnblogs.com/suinuaner/archive/2013/04/11/android_fifty.html

http://blog.csdn.net/lanjianhun/article/details/8675299

http://blog.csdn.net/alex0203/article/details/7646973

http://www.cnphp6.com/archives/58164

http://blog.csdn.net/weihan1314/article/details/8045993

转：

 package com.wyl.myasyctask;

 import java.io.InputStream;

 import android.app.Activity;
 import android.app.ProgressDialog;
 import android.content.Context;
 import android.graphics.Bitmap;
 import android.graphics.BitmapFactory;
 import android.os.AsyncTask;
 import android.os.Bundle;
 import android.util.Log;
 import android.view.View;
 import android.widget.Button;
 import android.widget.ImageView;

 public class MainActivity extends Activity {
     private static final String sImageUrl = "http://fashion.qqread.com/ArtImage/20110225/0083_13.jpg";
     private Button mLoadButton;
     private ImageView mImageView;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);

         Log.i("UI thread", " >> onCreate()");

         mImageView = (ImageView) this.findViewById(R.id.ImageVivew);

         mLoadButton = (Button) this.findViewById(R.id.LoadButton);
         mLoadButton.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v) {
                 LoadImageTask task = new LoadImageTask(v.getContext());
                 task.execute(sImageUrl);// 源码中得知,会调用onPreExecute()...方法
             }
         });

     }

     class LoadImageTask extends AsyncTask<String, Integer, Bitmap> {
         private ProgressDialog mProgressBar;

         LoadImageTask(Context context) {
             mProgressBar = new ProgressDialog(context);
             mProgressBar.setCancelable(true);
             mProgressBar.setMessage("setMessage()...");
             mProgressBar.setProgressStyle(ProgressDialog.STYLE_SPINNER);
             mProgressBar.setMax(100);
         }

         @Override
         protected Bitmap doInBackground(String... params) {
             System.out.println("doInBackground()...");

             Bitmap bitmap = null;

             try {
                 publishProgress(10);
                 Thread.sleep(1000);

                 InputStream in = new java.net.URL(sImageUrl).openStream();
                 publishProgress(60);
                 Thread.sleep(1000);

                 bitmap = BitmapFactory.decodeStream(in);
                 in.close();
             } catch (Exception e) {
                 e.printStackTrace();
             }

             publishProgress(100);
             return bitmap;
         }

         @Override
         protected void onCancelled() {
             super.onCancelled();
         }

         @Override
         protected void onPreExecute() {

             mProgressBar.setProgress(0);
             mProgressBar.setMessage("Image downloading ... 0%");
             mProgressBar.show();
             System.out.println("onPreExecute()...");
         }

         @Override
         protected void onPostExecute(Bitmap result) {
             System.out.println("onPostExecute()...");
             if (result != null) {
                 mProgressBar.setMessage("Image downloading success!");
                 mImageView.setImageBitmap(result);
             } else {
                 mProgressBar.setMessage("Image downloading failure!");
             }

             mProgressBar.dismiss();
         }

         @Override
         protected void onProgressUpdate(Integer... values) {
             System.out.println("onProgressUpdate()...");
             mProgressBar.setMessage("Image downloading ... %" + values[0]);
             mProgressBar.setProgress(values[0]);
         }
     }

 }

main.xml:

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/AbsoluteLayout01"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent"
     android:orientation="vertical" >

     <Button
         android:id="@+id/LoadButton"
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"
         android:text="Load">
     </Button>

     <ImageView
         android:id="@+id/ImageVivew"
         android:layout_width="match_parent"
         android:layout_height="400dip"
         android:scaleType="centerInside"
         android:padding="2dp">
     </ImageView>

 </LinearLayout>