Witam,
na wstępie przepraszam za mało klarowny temat, ale szczerze nie wiedziałem co napisać. Uczę się androida z Head First. Mój problem polega na tym, że mam kod jak w książce, a mimo to aplikacja nie działa. Dokładniej mówiąc po uruchomieniu jest pusty ekran, zero elementów (załącznik). Poniżej kod:
Parser
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.jar.Attributes;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
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 bitmap = BitmapFactory.decodeStream(input);
input.close();
return bitmap;
} catch (IOException ioe) {
return null;
}
}
public void startElement(String uri, String localName, String qName,
Attributes attributes) throws SAXException {
if (localName.equals("url")) { 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; }
}
Activity
import android.graphics.Bitmap;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ImageView;
import android.widget.TextView;
import org.w3c.dom.Text;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
IotdHandler handler = new IotdHandler();
handler.processFeed();
resetDisplay(handler.getTitle(), handler.getDate(), handler.getImage(), handler.getDescription());
}
private void resetDisplay(String title, String date, Bitmap imageUrl, StringBuffer description) {
TextView imageTitle = (TextView) findViewById(R.id.imageTitle);
imageTitle.setText(title);
TextView imageDate = (TextView) findViewById(R.id.imageDate);
imageDate.setText(date);
ImageView imageDisplay = (ImageView) findViewById(R.id.imageDisplay);
imageDisplay.setImageBitmap(imageUrl);
TextView imageDescription = (TextView) findViewById(R.id.imageDescription);
imageDescription.setText(description);
}
}
Output logcat
02-05 15:58:21.651 6001-6001/? I/art: Not late-enabling -Xcheck:jni (already on)
02-05 15:58:21.821 6001-6001/pl.example.nasadailyimage W/System: ClassLoader referenced unknown path: /data/app/pl.example.nasadailyimage-2/lib/x86
02-05 15:58:22.241 6001-6028/pl.example.nasadailyimage D/OpenGLRenderer: Use EGL_SWAP_BEHAVIOR_PRESERVED: true
02-05 15:58:22.376 6001-6028/pl.example.nasadailyimage I/OpenGLRenderer: Initialized EGL, version 1.4
02-05 15:58:22.465 6001-6028/pl.example.nasadailyimage W/EGL_emulation: eglSurfaceAttrib not implemented
02-05 15:58:22.469 6001-6028/pl.example.nasadailyimage W/OpenGLRenderer: Failed to set EGL_SWAP_BEHAVIOR on surface 0xad6f39e0, error=EGL_SUCCESS
Szczerze przyznam, że nie wiem co robię źle. Jak wspominałem to przykład z książki. Serdecznie dziękuję wszystkim za pomoc, przykład ten skutecznie zahamował mnie w dalszej nauce i muszę się z nim uporać :D
Pozdrawiam