Image Loader : Image « J2ME « Java
Image Loader
/*
Wireless Java 2nd edition
Jonathan Knudsen
Publisher: Apress
ISBN: 1590590775
*/
import java.io.*;
import javax.microedition.io.*;
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
public class ImageLoader extends MIDlet
implements CommandListener, Runnable {
private Display mDisplay;
private Form mForm;
public ImageLoader() {
mForm = new Form("Connecting...");
mForm.addCommand(new Command("Exit", Command.EXIT, 0));
mForm.setCommandListener(this);
}
public void startApp() {
if (mDisplay == null) mDisplay = Display.getDisplay(this);
mDisplay.setCurrent(mForm);
// Do network loading in a separate thread.
Thread t = new Thread(this);
t.start();
}
public void pauseApp() {}
public void destroyApp(boolean unconditional) {}
public void commandAction(Command c, Displayable s) {
if (c.getCommandType() == Command.EXIT)
notifyDestroyed();
}
public void run() {
HttpConnection hc = null;
DataInputStream in = null;
try {
String url = getAppProperty("ImageLoader-URL");
hc = (HttpConnection)Connector.open(url);
int length = (int)hc.getLength();
byte[] data = null;
if (length != -1) {
data = new byte[length];
in = new DataInputStream(hc.openInputStream());
in.readFully(data);
}
else {
// If content length is not given, read in chunks.
int chunkSize = 512;
int index = 0;
int readLength = 0;
in = new DataInputStream(hc.openInputStream());
data = new byte[chunkSize];
do {
if (data.length < index + chunkSize) {
byte[] newData = new byte[index + chunkSize];
System.arraycopy(data, 0, newData, 0, data.length);
data = newData;
}
readLength = in.read(data, index, chunkSize);
index += readLength;
} while (readLength == chunkSize);
length = index;
}
Image image = Image.createImage(data, 0, length);
ImageItem imageItem = new ImageItem(null, image, 0, null);
mForm.append(imageItem);
mForm.setTitle("Done.");
}
catch (IOException ioe) {
StringItem stringItem = new StringItem(null, ioe.toString());
mForm.append(stringItem);
mForm.setTitle("Done.");
}
finally {
try {
if (in != null) in.close();
if (hc != null) hc.close();
}
catch (IOException ioe) {}
}
}
}
