私は Head First Android Development のガイドに従っていますが、この部分を正しく理解できないようです。このコードは、Nasa RSS フィードからタイトルと説明を含む画像を取得することになっていますが、画像を取得していません。どんな助けでも素晴らしいでしょう:)
package com.olshausen.nasadailyimage;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;
import android.os.Bundle;
import android.widget.ImageView;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.view.Menu;
import android.widget.TextView;
public class DailyImage extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_daily_image);
IotdHandler handler = new IotdHandler ();
handler.processFeed();
resetDisplay (handler.getTitle(), handler.getDate(), handler.getImage(), handler.getDescription());
}
public class IotdHandler extends DefaultHandler {
private String url = "http://www.nasa.gov/rss/image_of_the_day.rss";
private boolean inUrl = false;
private boolean inTitle = false;
private boolean inDescription = false;
private boolean inItem = false;
private boolean inDate = false;
private Bitmap image = null;
private String title = null;
private StringBuffer description = new StringBuffer();
private String date = null;
public void processFeed() {
try {
SAXParserFactory factory =
SAXParserFactory.newInstance();
SAXParser parser = factory.newSAXParser();
XMLReader reader = parser.getXMLReader();
reader.setContentHandler(this);
InputStream inputStream = new URL(url).openStream();
reader.parse(new InputSource(inputStream));
} catch (Exception e) { }
}
private Bitmap getBitmap(String url) {
try {
HttpURLConnection connection = (HttpURLConnection)new URL(url).openConnection();
connection.setDoInput(true);
connection.connect();
InputStream input = connection.getInputStream();
Bitmap bilde = BitmapFactory.decodeStream(input);
input.close();
return bilde;
} catch (IOException ioe) { return null; }
}
public void startElement(String url, String localName, String qName, Attributes attributes) throws SAXException {
if (localName.endsWith(".jpg")) { inUrl = true; }
else { inUrl = false; }
if (localName.startsWith("item")) { inItem = true; }
else if (inItem) {
if (localName.equals("title")) { inTitle = true; }
else { inTitle = false; }
if (localName.equals("description")) { inDescription = true; }
else { inDescription = false; }
if (localName.equals("pubDate")) { inDate = true; }
else { inDate = false; }
}
}
public void characters(char ch[], int start, int length) { String chars = new String(ch).substring(start, start + length);
if (inUrl && url == null) { image = getBitmap(chars); }
if (inTitle && title == null) { title = chars; }
if (inDescription) { description.append(chars); }
if (inDate && date == null) { date = chars; }
}
public Bitmap getImage() { return image; }
public String getTitle() { return title; }
public StringBuffer getDescription() { return description; }
public String getDate() { return date; }
}
private void resetDisplay (String title, String date, Bitmap image, StringBuffer description) {
TextView titleView = (TextView) findViewById (R.id.image_title);
titleView.setText(title);
TextView dateView = (TextView) findViewById(R.id.image_date);
dateView.setText(date);
ImageView imageView = (ImageView) findViewById (R.id.image_display);
imageView.setImageBitmap(image);
TextView descriptionView = (TextView) findViewById (R.id.image_description);
descriptionView.setText(description);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_daily_image, menu);
return true;
}
}
私は正直に言って、このコードのほとんどをチェックせずにコピーしたと言わなければなりません。パーサーは「ready bake code」だったので、この章で扱うべき内容ではありません :)