List in J2ME

J2ME Canvas List Example will explain you, how to create list of items. In this example we are going to create a simple list of text, that will show the selected item on the same screen. In the example you can see that we have created a class and then a constructor of the same class. In the constructor we defined the list and added some items into it..

Syntax for creating a list


  public CanvasListExample() {

    canvas = new CanvasList();

    list = new List("Employee List", Choice.IMPLICIT);

    show = new Command("Show", Command.OK, 1);

    list.append("Miss. Anusmita", null);

    list.append("Miss. Neelam", null);

    list.append("Mr. Sandeep", null);

    list.append("Mr. Suman", null);

    list.append("Mr. Saurabh", null);

    list.addCommand(show);

    display = Display.getDisplay(this);

  }

You can add any number of elements into it using list.append ()

The simple list application will look like as follow..

List in J2ME

Source Code of CanvasListExample.java


import javax.microedition.midlet.*;

import javax.microedition.lcdui.*;



public class CanvasListExample extends MIDlet implements CommandListener{

  private Display display;

  private CanvasList canvas;

  private List list;

  private Command show;



  public CanvasListExample() {

    canvas = new CanvasList();

    list = new List("Employee List", Choice.IMPLICIT);

    show = new Command("Show", Command.OK, 1);

    list.append("Miss. Anusmita", null);

    list.append("Miss. Neelam", null);

    list.append("Mr. Sandeep", null);

    list.append("Mr. Suman", null);

    list.append("Mr. Saurabh", null);

    list.addCommand(show);

    display = Display.getDisplay(this);

  }



  public void startApp(){

    list.setCommandListener(this);

    display.setCurrent(list);

  }



  public void pauseApp() {}



  public void destroyApp(boolean unconditional){

    notifyDestroyed();

  }



  public void commandAction(Command c, Displayable d){

    String label = c.getLabel();

    if(label.equals("Show")){

      display.setCurrent(canvas);

    }

  }

  class CanvasList extends Canvas implements CommandListener{

    private Image image;

    private Command back;



    public CanvasList(){

      back = new Command ( "Back", Command.BACK, 1);

      addCommand (back);

      setCommandListener (this);

    }



    public void paint(Graphics g){

      int width = getWidth();

      int height = getHeight();

      String str = list.getString(list.getSelectedIndex());



      g.setColor(0, 0, 255);

      g.drawString(str, width/2, height/2, Graphics.HCENTER | Graphics.TOP);

    }



    public void commandAction(Command c, Displayable d){

      String label = c.getLabel();      

      if(label.equals("Back")){

        display.setCurrent(list);

      }

    }

  }

}

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