Fullscreen Landscape

Most handset screens are portrait: higher than wider. What if you want to show content in landscape mode? Since MIDP 2.0 we can use an Sprite to rotate an image in 90 degrees.

First thing we need is an Image of the correct size. Following code could be inside the constructor of a class that extends Canvas - considering an Sprite and an Image attributes:

int width = Math.max(super.getWidth(), super.getHeight());
int height = Math.min(super.getWidth(), super.getHeight());
screen = Image.createImage(width, height);
sprite = new Sprite(screen);
if (super.getWidth() < super.getHeight()) { // portrait screen
  sprite.setTransform(Sprite.TRANS_ROT90);
  sprite.setPosition(0, 0);
}

When painting your content use the mutable Image Graphics, then update the sprite with the image like bellow.

protected void paint(Graphics g1) {
  Graphics g = screen.getGraphics();
  // ... do your drawing
  this.sprite.setImage(screen, screen.getWidth(), screen.getHeight());
  sprite.paint(g1);
}

How can you use the biggest possible area on the handset display?

1. Do not setTitle on your Canvas


2. Do not addCommand to your Canvas


3. Call setFullScreenMode(true) before calling super.getWidth() and super.getHeight()

Open File Dialog

Ok, this is not a Dialog... It is an Implicit List. As we do not have File Dialogs on LCDUI I decided to share my version with you. It did work with Sony Ericson and Motorola iDEN handsets and I use it in my Books application.

import java.io.IOException;
import java.util.Enumeration;
import java.util.Stack;

import javax.microedition.io.Connector;
import javax.microedition.io.file.FileConnection;
import javax.microedition.io.file.FileSystemRegistry;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.List;
import javax.microedition.lcdui.Ticker;


public class OpenFileDialog extends List 
  implements CommandListener
{
  public static final String PREFIX = "file:///";
  private static final String UP = "[ .. ]";
  private static final String DIR = " + ";
  private Stack stack = new Stack();
  private OpenFileListener listener;
  private CommandListener commandListener;
  private String extension;

  public OpenFileDialog (OpenFileListener listener, 
     String title, String extension)
  {
    super(title, List.IMPLICIT);
    super.setCommandListener(this);
    this.listener = listener;
    this.extension = extension;
    addRoots();
  }

  public void setCommandListener(CommandListener l) {
    this.commandListener = l;
  }

  public void commandAction(Command c, Displayable d) {
    if (c == List.SELECT_COMMAND) {
      this.changeSelection();
    } else {
      if (this.commandListener != null) {
        this.commandListener.commandAction(c, d);
      }
    }
  }

  private String getSelectedText () {
    int index = getSelectedIndex();
    if (index < 0 || index >= this.size()) {
      return "";
    }
    return this.getString(index);
  }

  private void changeSelection () {
    String target = this.getSelectedText();
    String parent = null;
    boolean goingUp = false;

    if (UP.equals(target)) {
      goingUp = true;
      stack.pop();
      if (stack.isEmpty() == false) {
        target = (String) stack.peek();
      } else {
        super.deleteAll();
        addRoots();
        this.setTicker(null);
        return;
      }
    } else {
      if (stack.isEmpty() == false) {
        parent = stack.peek().toString();
      }
    }

    try {
      if (target.startsWith(DIR)) {
        target = target.substring(3);
      }
      if (parent != null) {
        target = parent + target;
      }
      this.setTicker(new Ticker(target));
      FileConnection fc = (FileConnection)
          Connector.open(PREFIX + target, Connector.READ);
      if (fc.isDirectory()) {
        super.deleteAll();
        if (goingUp == false) {
          stack.push(target);
        }
        super.append(UP, null);
        
        Enumeration entries = fc.list();
        
        while (entries.hasMoreElements()) {
          String entry = (String) entries.nextElement();
          FileConnection fc2 = (FileConnection) 
              Connector.open(PREFIX + target + entry,
              Connector.READ);
          if (fc2.isDirectory()) {
            super.append(DIR + entry, null);
          } else if (entry.toLowerCase().endsWith(extension)) {
            super.append(entry, null);
          }
          fc2.close();
        }
        fc.close();
      } else {
        this.listener.fileSelected(fc);
      }
    } catch (IOException e) {
      e.printStackTrace();
    }
    
  }

  private void addRoots() {
    Enumeration roots = FileSystemRegistry.listRoots();
    while (roots.hasMoreElements()) {
      super.append(DIR + roots.nextElement().toString(), null);
    }
  }

}

Related topics:

• Books: a new study case


• Use LCDUI