布局文件：
activity_main.xml
<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" > <ListView android:id="@+id/imageList" android:layout_width="match_parent" android:layout_height="wrap_content" /></RelativeLayout>list_item.xml
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="vertical" android:padding="10dp" > <ImageView android:id="@+id/thumbnail" android:layout_width="wrap_content" android:layout_height="wrap_content" android:contentDescription="@string/image" /> </LinearLayout>RowItem.java
import android.graphics.Bitmap;public class RowItem { private Bitmap bitmapImage; public RowItem(Bitmap bitmap) { this.bitmapImage = bitmap; } public Bitmap getBitmap() { return bitmapImage; } public void setBitmap(Bitmap bitmap) { this.bitmapImage = bitmap; }}
FileUtils.java
import java.io.InputStream;import java.io.OutputStream;public class FileUtils { public static void close(InputStream in) { if (in != null) { try { in.close(); } catch (Exception e) { e.printStackTrace(); } } } public static void close(OutputStream out) { if (out != null) { try { out.close(); } catch (Exception e) { e.printStackTrace(); } } }}
CustomListViewAdapter.java
import java.util.List;import android.app.Activity;import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.ImageView;public class CustomListViewAdapter extends BaseAdapter { Context mContext; List<RowItem> rowItems; public CustomListViewAdapter(Context context, List<RowItem> items) { this.mContext = context; this.rowItems = items; } private class ViewHolder { ImageView imageView; } @Override public int getCount() { return rowItems.size(); } @Override public Object getItem(int position) { return rowItems.get(position); } @Override public long getItemId(int position) { return 0; } @Override public View getView(int position, View convertView, ViewGroup parent) { ViewHolder holder = null; LayoutInflater inflater = (LayoutInflater)mContext.getSystemService(Activity.LAYOUT_INFLATER_SERVICE); if (convertView == null) { convertView = inflater.inflate(R.layout.list_item, null); holder = new ViewHolder(); holder.imageView = (ImageView) convertView.findViewById(R.id.thumbnail); convertView.setTag(holder); } else { holder = (ViewHolder) convertView.getTag(); } RowItem rowItem = (RowItem) rowItems.get(position); holder.imageView.setImageBitmap(rowItem.getBitmap()); return convertView; }}
MainActivity.java
import java.io.BufferedInputStream;import java.io.BufferedOutputStream;import java.io.ByteArrayOutputStream;import java.io.InputStream;import java.net.URL;import java.net.URLConnection;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.view.Menu;import android.widget.ListView;//记得在manifest.xml中添加访问网络的权限public class MainActivity extends Activity { ProgressDialog progressDialog; CustomListViewAdapter listViewAdapter; ListView listView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); listView = (ListView) findViewById(R.id.imageList); DownloadTask task = new DownloadTask(this); task.execute(new String[]{URL, URL1, URL2}); progressDialog = new ProgressDialog(this); progressDialog.setTitle("In progress..."); progressDialog.setMessage("Loading..."); progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL); progressDialog.setIndeterminate(false); progressDialog.setMax(100); progressDialog.setCancelable(true); progressDialog.show(); } private class DownloadTask extends AsyncTask<String, Integer, List<RowItem> > { private Activity context; List<RowItem> rowItems; int taskCount; public DownloadTask(Activity context) { this.context = context; } @Override protected List<RowItem> doInBackground(String... urls) { taskCount = urls.length; rowItems = new ArrayList<RowItem>(); Bitmap map = null; for (String url : urls) { map = downloadImage(url); rowItems.add(new RowItem(map)); } return rowItems; } protected void onProgressUpdate(Integer... progress) { progressDialog.setProgress(progress[0]); if (rowItems != null) { progressDialog.setMessage("Loading " + (rowItems.size() + 1) + "/" + taskCount); } } @Override protected void onPostExecute(List<RowItem> rowItems) { listViewAdapter = new CustomListViewAdapter(context, rowItems); listView.setAdapter(listViewAdapter); progressDialog.dismiss(); } private Bitmap downloadImage(String urlString) { int count = 0; Bitmap bitmap = null; URL url; InputStream in = null; BufferedOutputStream out = null; try { url = new URL(urlString); URLConnection conn = url.openConnection(); int lengthOfFile = conn.getContentLength(); in = new BufferedInputStream(url.openStream()); ByteArrayOutputStream dataStream = new ByteArrayOutputStream(); out = new BufferedOutputStream(dataStream); byte[] data = new byte[512]; long total = 0L; while ((count = in.read(data)) != -1) { total += count; publishProgress((int)((total * 100) / lengthOfFile)); out.write(data, 0, count); } out.flush(); BitmapFactory.Options options = new BitmapFactory.Options(); options.inSampleSize = 1; byte[] bytes = dataStream.toByteArray(); bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length); } catch (Exception e) { e.printStackTrace(); } return bitmap; } } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } //URL地址 public static final String URL = "http://gdown.baidu.com/data/wisegame/60288c8f92238775/FruitNinja_1809.apk"; public static final String URL1 ="http://gdown.baidu.com/data/wisegame/60288c8f92238775/FruitNinja_1809.apk"; public static final String URL2 = "http://gdown.baidu.com/data/wisegame/60288c8f92238775/FruitNinja_1809.apk"; }