This example implements the following features in one Midlet:

  • Implementing Pie Charts and Bar Charts
  • How to use multiple choices
  • How to use exclusive lists
  • ...

 

 /*
 * @(#)Sample.java  1.9 01/06/08
 * Copyright (c) 1999-2001 Sun Microsystems, Inc. All Rights Reserved.
 */

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;


/*
 * A quick sample of graphics,  commands, and event handling.
 */
public class SampleCanvasMIDlet extends MIDlet implements CommandListener {
    Display display;
    Command exitCommand;
    Command backCommand;
    Command okCommand;
    SampleCanvas sample; // Instance of sample canvas

    List itemMenu;
    List exclusiveList;
    List multipleList;
    TextBox textbox;
    Ticker ticker;
    Alert alert;
    Form form;
    StringItem stringItem;
    ImageItem imageItem;
    Image image;
    TextField textItem;
    ChoiceGroup choiceItem;
    DateField dateItem;
    Gauge gaugeItem;


    public SampleCanvasMIDlet() {
        display = Display.getDisplay(this);
        exitCommand = new Command("Exit", Command.EXIT, 1);
        backCommand = new Command("Back", Command.BACK, 2);
        okCommand = new Command("OK", Command.OK, 3);

        ticker = new Ticker("Select an item to display");
        itemMenu = new List(null, Choice.IMPLICIT);
        itemMenu.append("Canvas", null);
        itemMenu.append("Form", null);
        itemMenu.append("Alert", null);
        itemMenu.append("TextBox", null);
        itemMenu.append("Exclusive List", null);
        itemMenu.append("Multiple Choice", null);

        itemMenu.setCommandListener(this);
        itemMenu.addCommand(exitCommand);
        itemMenu.setTicker(ticker);
        display.setCurrent(itemMenu);
    }

    public void startApp () {
    }

    public void destroyApp (boolean unconditional) {
    }

    public void pauseApp () {
    }

    public void commandAction(Command c, Displayable s) {
        if (c == backCommand) {
            display.setCurrent(itemMenu);
        } else if (s == itemMenu) {
            if (c == List.SELECT_COMMAND) {
                // Handle the item sected to be displayed
                int i = itemMenu.getSelectedIndex();
                switch (i) {
                    case 0: // Show Sample canvas              display.setCurrent(getCanvas());
                        break;
                    case 1: // Show the form
                        display.setCurrent(getForm());
                        break;
                    case 2: // Show an alert
                        display.setCurrent(getAlert("Warning", 
                                "This window will dismiss in two seconds."));
                        break;
                    case 3: // Show TextBox
                        display.setCurrent(getTextBox());
                        break;
                    case 4: // Show Exclusive list
                        display.setCurrent(getExclusiveList());
                        break;
                    case 5: // Show Multiple List
                        display.setCurrent(getMultipleList());
                        break;
                }
            } else if (c == exitCommand) {
                notifyDestroyed();
            }
        } else if (s == exclusiveList) {
            int i = exclusiveList.getSelectedIndex();
            String value = exclusiveList.getString(i);
            alert = getAlert("Border selected:", value);
            display.setCurrent(alert, itemMenu);
        } else if (s == multipleList) {
            StringBuffer b = new StringBuffer();
            for (int i = 0; i <= 2; i++) {
                if (multipleList.isSelected(i)) {
                    b.append(multipleList.getString(i));
                    b.append("\n");
                }
            }
            alert = getAlert("Colors selected:", b.toString());
            display.setCurrent(alert, itemMenu);
        } else if (s == textbox) {
            String value = textbox.getString();
            alert = getAlert("Text Entered:", value);
            display.setCurrent(alert, itemMenu);
        } else if (s == form) {
            alert = getAlert("Image options  saved", "");
            display.setCurrent(alert, itemMenu);
        }
    }

    SampleCanvas getCanvas() {
        if (sample == null) {
            sample = new SampleCanvas();
            sample.addCommand(backCommand);
            sample.setCommandListener(this);
        }
        return sample;
    }

    List getExclusiveList() {
        if (exclusiveList == null) {
            exclusiveList = new List("Border Style", Choice.EXCLUSIVE);
            exclusiveList.append("None", null);
            exclusiveList.append("Plain", null);
            exclusiveList.append("Fancy", null);
            exclusiveList.addCommand(backCommand);
            exclusiveList.addCommand(okCommand);
            exclusiveList.setCommandListener(this);
        }
        return exclusiveList;
    }

    List getMultipleList() {
        if (multipleList == null) {
            multipleList = new List("Colors to mix", Choice.MULTIPLE);
            multipleList.append("Red", null);
            multipleList.append("Green", null);
            multipleList.append("Blue", null);
            multipleList.addCommand(backCommand);
            multipleList.addCommand(okCommand);
            multipleList.setCommandListener(this);
        }
        return multipleList;
    }

    TextBox getTextBox() {
        if (textbox == null) {
            textbox = new TextBox("Enter a phone number","", 40,
          TextField.PHONENUMBER);
            textbox.addCommand(backCommand);
            textbox.addCommand(okCommand);
            textbox.setCommandListener(this);
        }
        return textbox;
    }
    Alert getAlert(String title, String contents) {
        if (alert == null) {
            alert = new Alert(title);
            alert.setType(AlertType.WARNING);
            alert.setTimeout(2000);
      alert.setString(contents); 
        } else {
            alert.setTitle(title);
            alert.setString(contents);
        }
        return alert;
    }
    Form getForm() {
         if (form == null) {
            form = new Form("Options");

            try {     image = Image.createImage("/images/PhotoAlbum.png");
                imageItem = new ImageItem("Preview:", image, 
                            ImageItem.LAYOUT_NEWLINE_BEFORE, "Mountain");
                form.append(imageItem);
            } catch (java.io.IOException ex) {
            }

            textItem = new TextField("Title:", "Mountain", 32,
             TextField.ANY);
            form.append(textItem);
            dateItem = new DateField("Date:", DateField.DATE);
            dateItem.setDate(new java.util.Date());
            form.append(dateItem);

            choiceItem = new ChoiceGroup("Size:", Choice.EXCLUSIVE);
            choiceItem.append("Small", null);
            choiceItem.append("Large", null);
            form.append(choiceItem);
            gaugeItem = new Gauge("Speed:", true, 10, 5);
            form.append(gaugeItem);

            form.addCommand(backCommand);
            form.addCommand(okCommand);
            form.setCommandListener(this);
        }
        return form;
    }
}


class SampleCanvas extends Canvas {
    int     x, y;           // Location of cross hairs
    String  event = "";     // Last key event type
    int     keyCode;        // Last keyCode pressed
    Font    font;           // Font used for drawing text
    int     fh;             // height of the font
    int     w, h;           // width and height of the canvas
    int     titleHeight;    // Height of the title
    int     pieSize;        // Size of the Pie chart used for width and height
    int     barSize;        // Size of the Bar chart used for width and height
    int     eventHeight;    // Size of the event region
    int     pad;            // Padding used between items

    SampleCanvas() {
        w = getWidth();
        h = getHeight();
        font = Font.getFont(Font.FACE_SYSTEM,
          Font.STYLE_PLAIN, Font.SIZE_SMALL);
        fh = font.getHeight();

        /* Compute the sizes of the bar and pie charts   * It should use all the space 
   * except for the title and event regions.
         * Don't let the charts get too small
         */
        pad = 2;
        titleHeight = fh + pad * 2;
        eventHeight = fh * 3;
        barSize = h - (titleHeight + pad) - (eventHeight + pad);
        if (barSize < 20)               // Don't let them get too small
            barSize = 20;
        if (barSize > (w - pad) / 2)    // Shrink to 1/2 width
            barSize = (w - pad) / 2;
        pieSize = barSize;
    }

    protected void keyPressed(int key) {
        keyCode = key;
        event = "Pressed";
        handleActions(key);
        repaint();
    }

    protected void keyRepeated(int key) {
        keyCode = key;
        event = "Repeated";
        handleActions(key);
        repaint();
    }

    protected void keyReleased(int key) {
        keyCode = key;
        event = "Released";
        repaint();
    }

    protected void pointerPressed(int x, int y) {
        this.x = x;
        this.y = y;
        keyCode = 0;
        event = "Pressed";
        repaint();
    }
    protected void pointerReleased(int x, int y) {
        this.x = x;
        this.y = y;
        keyCode = 0;
        event = "Released";
        repaint();
    }

    protected void pointerDragged(int x, int y) {
        this.x = x;
        this.y = y;
        keyCode = 0;
        event = "Dragged";
    }

    void handleActions(int keyCode) {
        int action = getGameAction(keyCode);
        switch (action) {
            case LEFT:
            x -= 1;
            break;
            case RIGHT:
            x += 1;
            break;
            case UP:
            y -= 1;
            break;
            case DOWN:
            y += 1;
            break;
        }
    }

    protected void paint(Graphics g) {

        g.setFont(font);
        g.setGrayScale(255);
        g.fillRect(0, 0, w, h);

        x = (x < 0) ? w - 1 : x;
        y = (y < 0) ? h - 1 : y;
        x = x % w;
        y = y % h;

        // Draw Fill and outline for background of title Text
        int swidth = pad * 2 + font.stringWidth("Pie and Bar Samples");
        int title_x = (w - swidth)/2;

        g.setGrayScale(128);
        g.fillRoundRect(title_x, 0, swidth, fh, 5, 5);
        g.setGrayScale(0);
        g.drawRoundRect(title_x, 0, swidth, fh, 5, 5);

        // Sample Text
        g.setColor(0, 0, 0);
        g.drawString("Pie and Bar Samples", 
         title_x + pad, pad, Graphics.TOP|Graphics.LEFT);

  // Translate to below title text
        g.translate(0, titleHeight + pad);

        /*
   * Draw pie chart on the left side
   * using the barSize for width and height
   */
        g.setColor(255, 0, 0);
        g.fillArc(0, 0, pieSize, pieSize, 45, 270);
        g.setColor(0, 255, 0);
        g.fillArc(0, 0, pieSize, pieSize, 0, 45);
        g.setColor(0, 0, 255);
        g.fillArc(0, 0, pieSize, pieSize, 0, -45);
        g.setColor(0);
        g.drawArc(0, 0, pieSize, pieSize, 0, 360);

        // Draw Bar chart on right side of the display
        // scale the values to the pieSize maximum value
        int yorig = barSize;
        int h1 = barSize / 3, h2 = barSize / 2, h3 = barSize;
        int avg = (h1 + h2 + h3) / 3;

        // Move over to draw Bar chart
        g.translate((w + pad) / 2, 0);

        int bw = pieSize / 7;
        if (bw < 2)
             bw = 2;
        g.setColor(255, 0, 0);
        g.fillRect(bw*1, yorig-h1, bw+1, h1);
        g.setColor(0, 255, 0);
        g.fillRect(bw*3, yorig-h2, bw+1, h2);
        g.setColor(0, 0, 255);
        g.fillRect(bw*5, yorig-h3, bw+1, h3);
        g.setColor(0);
        g.drawRect(bw*1, yorig-h1, bw, h1);
        g.drawRect(bw*3, yorig-h2, bw, h2);
        g.drawRect(bw*5, yorig-h3, bw, h3);

        // Draw axis for bar chart.
        g.setGrayScale(0);
        g.drawLine(0, 0, 0, yorig);
        g.drawLine(0, yorig, barSize, yorig);
        g.setStrokeStyle(Graphics.DOTTED);
        g.drawLine(0, yorig - avg, barSize, yorig-avg);
        g.setStrokeStyle(Graphics.SOLID);

  // Restore to left and move down
        g.translate(-(w + pad) / 2, pieSize + pad);

        // Draw the key and pointer status
        g.setColor(128, 128, 128);
        int col1 = font.stringWidth("Action:");
        g.drawString("Key: ",      col1,     0,
         Graphics.TOP|Graphics.RIGHT);
        g.drawString(keyString(keyCode), col1, 0,
         Graphics.TOP|Graphics.LEFT);
        g.drawString("Action:",    col1,     fh,
         Graphics.TOP|Graphics.RIGHT);
        g.drawString(actionString(keyCode), col1, fh,
         Graphics.TOP|Graphics.LEFT);
        g.drawString("Event:",     col1,     fh*2,
         Graphics.TOP|Graphics.RIGHT);
        g.drawString(event,        col1,     fh*2,
         Graphics.TOP|Graphics.LEFT);
        int col2 = 80;
        g.drawString("x:",         col2,     0,
         Graphics.TOP|Graphics.RIGHT);
        g.drawString(Integer.toString(x), col2, 0,
         Graphics.TOP|Graphics.LEFT);
        g.drawString("y:",         col2,     fh,
         Graphics.TOP|Graphics.RIGHT);
        g.drawString(Integer.toString(y), col2, fh,
         Graphics.TOP|Graphics.LEFT);

        // Restore the origin and draw the crosshairs on top
        g.translate(-g.getTranslateX(), -g.getTranslateY());

        g.setColor(0, 0, 0);
        g.drawLine(x, y - 5, x, y + 5);
        g.drawLine(x - 5, y, x + 5, y);
    }
    String keyString(int keyCode) {
        if (keyCode == 0) {
            return "";
        }
        return Integer.toString(keyCode);
    }

    String actionString(int keyCode) {
        if (keyCode == 0) {
            return "";
        }

  int action = getGameAction(keyCode);
  switch (action) {
  case FIRE:
      return "Fire";
  case LEFT:
      return "Left";
  case RIGHT:
      return "Right";
  case DOWN:
      return "Down";
  case UP:
      return "Up";
  case GAME_A:
      return "Game A";
  case GAME_B:
      return "Game B";
  case GAME_C:
      return "Game C";
  case GAME_D:
      return "Game D";
  case 0:
      return "";
  default:
      return Integer.toString(action);
  }
    }
}

 

 

 

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