Android4高级编程的源代码

package net.learn2develop.Networking; import android.app.Activity; import android.os.Bundle; import java.io.IOException; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.URL; import java.net.URLConnection; import android.util.Log; import android.widget.ImageView; import android.widget.Toast; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.AsyncTask; import java.io.InputStreamReader; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.Node; import org.w3c.dom.NodeList; public class NetworkingActivity extends Activity { ImageView img; private InputStream OpenHttpConnection(String urlString) throws IOException { InputStream in = null; int response = -1; URL url = new URL(urlString); URLConnection conn = url.openConnection(); if (!(conn instanceof HttpURLConnection)) throw new IOException("Not an HTTP connection"); try{ HttpURLConnection httpConn = (HttpURLConnection) conn; httpConn.setAllowUserInteraction(false); httpConn.setInstanceFollowRedirects(true); httpConn.setRequestMethod("GET"); httpConn.connect(); response = httpConn.getResponseCode(); if (response == HttpURLConnection.HTTP_OK) { in = httpConn.getInputStream(); } } catch (Exception ex) { Log.d("Networking", ex.getLocalizedMessage()); throw new IOException("Error connecting"); } return in; } private Bitmap DownloadImage(String URL) { Bitmap bitmap = null; InputStream in = null; try { in = OpenHttpConnection(URL); bitmap = BitmapFactory.decodeStream(in); in.close(); } catch (IOException e1) { Log.d("NetworkingActivity", e1.getLocalizedMessage()); } return bitmap; } /* private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> { protected Bitmap doInBackground(String... urls) { return DownloadImage(urls[0]); } protected void onPostExecute(Bitmap result) { ImageView img = (ImageView) findViewById(R.id.img); img.setImageBitmap(result); } } */ private class DownloadImageTask extends AsyncTask <String, Bitmap, Long> { //---takes in a list of image URLs in String type--- protected Long doInBackground(String... urls) { long imagesCount = 0; for (int i = 0; i < urls.length; i++) { //---download the image--- Bitmap imageDownloaded = DownloadImage(urls[i]); if (imageDownloaded != null) { //---increment the image count--- imagesCount++; try { //---insert a delay of 3 seconds--- Thread.sleep(3000); } catch (InterruptedException e) { e.printStackTrace(); } //---return the image downloaded--- publishProgress(imageDownloaded); } } //---return the total images downloaded count--- return imagesCount; } //---display the image downloaded--- protected void onProgressUpdate(Bitmap... bitmap) { img.setImageBitmap(bitmap[0]); } //---when all the images have been downloaded--- protected void onPostExecute(Long imagesDownloaded) { Toast.makeText(getBaseContext(), "Total " + imagesDownloaded + " images downloaded" , Toast.LENGTH_LONG).show(); } } private String DownloadText(String URL) { int BUFFER_SIZE = 2000; InputStream in = null; try { in = OpenHttpConnection(URL); } catch (IOException e) { Log.d("NetworkingActivity", e.getLocalizedMessage()); return ""; } InputStreamReader isr = new InputStreamReader(in); int charRead; String str = ""; char[] inputBuffer = new char[BUFFER_SIZE]; try { while ((charRead = isr.read(inputBuffer))>0) { //---convert the chars to a String--- String readString = String.copyValueOf(inputBuffer, 0, charRead); str += readString; inputBuffer = new char[BUFFER_SIZE]; } in.close(); } catch (IOException e) { Log.d("NetworkingActivity", e.getLocalizedMessage()); return ""; } return str; } private class DownloadTextTask extends AsyncTask<String, Void, String> { protected String doInBackground(String... urls) { return DownloadText(urls[0]); } @Override protected void onPostExecute(String result) { Toast.makeText(getBaseContext(), result, Toast.LENGTH_LONG).show(); } } private String WordDefinition(String word) { InputStream in = null; String strDefinition = ""; try { in = OpenHttpConnection( "http://services.aonaware.com/DictService/DictService.asmx/Define?word=" + word); Document doc = null; DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); DocumentBuilder db; try { db = dbf.newDocumentBuilder(); doc = db.parse(in); } catch (ParserConfigurationException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } doc.getDocumentElement().normalize(); //---retrieve all the <Definition> elements--- NodeList definitionElements = doc.getElementsByTagName("Definition"); //---iterate through each <Definition> elements--- for (int i = 0; i < definitionElements.getLength(); i++) { Node itemNode = definitionElements.item(i); if (itemNode.getNodeType() == Node.ELEMENT_NODE) { //---convert the Definition node into an Element--- Element definitionElement = (Element) itemNode; //---get all the <WordDefinition> elements under // the <Definition> element--- NodeList wordDefinitionElements = (definitionElement).getElementsByTagName( "WordDefinition"); strDefinition = ""; //---iterate through each <WordDefinition> elements--- for (int j = 0; j < wordDefinitionElements.getLength(); j++) { //---convert a <WordDefinition> node into an Element--- Element wordDefinitionElement = (Element) wordDefinitionElements.item(j); //---get all the child nodes