Sample of graphics, commands, and event handling.


/*
* @(#)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); } } }