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>