Java Tutorial/J2ME/Arc

Draw arc

   <source lang="java">

import javax.microedition.lcdui.Canvas; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Graphics; import javax.microedition.midlet.MIDlet; public class DrawArcGraphicsMIDlet extends MIDlet {

 private Display display;
 protected void startApp() {
   Canvas canvas = new LineCanvas();
   display = Display.getDisplay(this);
   display.setCurrent(canvas);
 }
 protected void pauseApp() {
 }
 protected void destroyApp(boolean unconditional) {
 }

} class LineCanvas extends Canvas {

 public void paint(Graphics g) {
   int width = getWidth();
   int height = getHeight();
   g.setColor(0);
   g.setStrokeStyle(Graphics.SOLID);
       g.drawArc(0, 0, width/2, height/2, 0, 90);

 }

}</source>

Fill an arc, change new color and fill a rectangle

   <source lang="java">

import javax.microedition.lcdui.Canvas; import javax.microedition.lcdui.rumand; import javax.microedition.lcdui.rumandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.Graphics; import javax.microedition.midlet.MIDlet; public class J2MEArcExample extends MIDlet {

 private Display display;
 private MyCanvas canvas;
 public J2MEArcExample() {
   display = Display.getDisplay(this);
   canvas = new MyCanvas(this);
 }
 protected void startApp() {
   display.setCurrent(canvas);
 }
 protected void pauseApp() {
 }
 protected void destroyApp(boolean unconditional) {
 }
 public void exitMIDlet() {
   destroyApp(true);
   notifyDestroyed();
 }

} class MyCanvas extends Canvas implements CommandListener {

 private Command exit;
 private J2MEArcExample arcExample;
 public MyCanvas(J2MEArcExample arcExample) {
   this.arcExample = arcExample;
   exit = new Command("Exit", Command.EXIT, 1);
   addCommand(exit);
   setCommandListener(this);
 }
 protected void paint(Graphics graphics) {
   graphics.setColor(255, 255, 255);
   graphics.fillRect(0, 0, getWidth(), getHeight());
   graphics.setColor(255, 0, 0);
   graphics.drawArc(0, 0, getWidth(), getHeight(), 180, 180);
 }
 public void commandAction(Command command, Displayable displayable) {
   if (command == exit) {
     arcExample.exitMIDlet();
   }
 }

}</source>

Fill arc

   <source lang="java">

import javax.microedition.lcdui.Canvas; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Graphics; import javax.microedition.midlet.MIDlet; public class FillArcGraphicsMIDlet extends MIDlet {

 private Display display;
 protected void startApp() {
   Canvas canvas = new LineCanvas();
   display = Display.getDisplay(this);
   display.setCurrent(canvas);
 }
 protected void pauseApp() {
 }
 protected void destroyApp(boolean unconditional) {
 }

} class LineCanvas extends Canvas {

 public void paint(Graphics g) {
   int width = getWidth();
   int height = getHeight();
   g.setColor(0);
   g.setStrokeStyle(Graphics.SOLID);
   g.fillArc(0, 0, width/2, height/2, 0, 90);

 }

}</source>

Pie chart

   <source lang="java">

import javax.microedition.lcdui.Canvas; import javax.microedition.lcdui.rumand; import javax.microedition.lcdui.rumandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.Graphics; import javax.microedition.midlet.MIDlet; public class PieChartMIDlet extends MIDlet implements CommandListener {

 private Command exitCommand;
 public void startApp() {
   Display display = Display.getDisplay(this);
   int[] data = { 10, 20, 30, 40, 20 };
   Displayable d = new PieChartCanvas(data);
   exitCommand = new Command("exit", Command.EXIT, 1);
   d.addCommand(exitCommand);
   d.setCommandListener(this);
   display.setCurrent(d);
 }
 public void pauseApp() {
 }
 public void destroyApp(boolean unconditional) {
 }
 public void commandAction(Command c, Displayable s) {
   notifyDestroyed();
 }

} class PieChartCanvas extends Canvas {

 int[] data;
 int colors[] = { 0xFF0000, 0xA9E969, 0x00FFFF, 0xC675EC, 0x008800, 0x00C400 };
 public PieChartCanvas(int[] data) {
   this.data = data;
 }
 public void paint(Graphics g) {
   int width = this.getWidth();
   int height = this.getHeight();
   g.setColor(255, 255, 255);
   g.fillRect(0, 0, width, height);
   int sum = 0;
   for (int i = 0; i < data.length; i++) {
     sum += data[i];
   }
   int deltaAngle = 360 * 100 / sum / 100;
   int x = 4;
   int y = 4;
   int diameter;
   if (width > height)
     diameter = height - y * 2;
   else
     diameter = width - x * 2;
   int startAngle = 0;
   for (int i = 0; i < data.length; i++) {
     g.setColor(colors[i]);
     g.fillArc(x, y, diameter, diameter, startAngle, deltaAngle * data[i]);
     startAngle += deltaAngle * data[i];
   }
 }

}</source>