AsyncTask 异步任务下载网络图片

package com.qf.day07_asynctask_03;

import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.app.ProgressDialog;
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.ImageView;
import android.widget.Toast;

public class MainActivity extends Activity {

private ImageView iv01,iv02;

private String urlStr01 = "http://www.818dxs.com/uploads/allimg/160430/1-160430154611959.png";
private String urlStr02 = "http://upload.cbg.cn/2015/1126/1448506973451.jpg";

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

iv01 =(ImageView) findViewById(R.id.iv01);
iv02 = (ImageView) findViewById(R.id.iv02);

}

public void downLoad(View v)
{
//启动异步任务, 下载图片

new MyTask().execute(urlStr01,urlStr02);
}

public class MyTask extends AsyncTask<String, Void, List<Bitmap>>
{

private ProgressDialog pDialog;

@Override
protected void onPreExecute() {
// TODO 初始化进度条对话框
super.onPreExecute();

pDialog = new ProgressDialog(MainActivity.this);

pDialog.setIcon(R.drawable.ic_launcher);

pDialog.setTitle("提示");

pDialog.setMessage("正在加载,请稍后...");

pDialog.setCancelable(false);

pDialog.show();
}

@Override
protected List<Bitmap> doInBackground(String... params) {
// TODO 执行耗时的操作

List<Bitmap> data = new ArrayList<Bitmap>();

try {

for(int i=0;i<params.length;i++)
{
URL url = new URL(params[i]);

HttpURLConnection conn = (HttpURLConnection) url.openConnection();

conn.setRequestMethod("GET");

conn.connect();

if(conn.getResponseCode() == 200)
{
InputStream is = conn.getInputStream();

Bitmap  bitmap = BitmapFactory.decodeStream(is);

data.add(bitmap);

}
}

} catch (Exception e) {
// TODO: handle exception
}

return data;
}

@Override
protected void onPostExecute(List<Bitmap> result) {
// TODO 对话框消失, 更新UI
super.onPostExecute(result);

pDialog.dismiss();

if(result!=null && result.size()>0)
{
Log.i("info", "--"+result.size());

iv01.setImageBitmap(result.get(0));

iv02.setImageBitmap(result.get(1));
}
else
{
Toast.makeText(MainActivity.this, "加载失败", Toast.LENGTH_LONG).show();
}
}
}

}

}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="下载图片"
android:id="@+id/button"
android:onClick="download"
android:layout_centerHorizontal="true"
/>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/iv1"
android:layout_below="@+id/button"
android:layout_centerHorizontal="true"
android:src="@drawable/ic_launcher"
/>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/iv2"
android:layout_below="@+id/iv1"
android:layout_centerHorizontal="true"
android:src="@drawable/ic_launcher"
/>
</RelativeLayout>