j2me学习笔记【13】——创建矩形框、圆角矩形以及填充颜色小例子

    可以通过标记左上角和右下角的坐标来定义矩形的尺寸。在画布上可以绘制4中矩形，分别是矩形框、填充矩形、圆角矩形框、圆角填充矩形。
    可以调用drawRect()方法创建矩形框，调用fillRect()方法填充矩形。需要4个参数，前两个是矩形的左上角坐标(x1,y1)，后两个参数是的宽度和高度(x2,y2)。
    必须在绘制举行前，使用setColor()方法设定用于绘制矩形的颜色。否则，就使用图形环境的当前颜色既绘制矩形的边框又填充矩形的内部，这依赖于要绘制的矩形的类型。
    生成一个圆角矩形和生成一个直角矩形的方法类似，只是必须指定用于兴城圆角的圆弧的水平直径和垂直直径。水平直径称为圆弧的宽度，垂直直径称为圆弧的高度。
    直径代表角的尖锐程度，即直径越小角越尖。水平直径和垂直直径都被定义成整数类型。
    可以分别调用drawRoundRect()方法和fillRoundRect()方法生成圆角矩形。这两个方法都需要6个参数。前4个参数标识了矩形的左上角坐标和右下角坐标。第5和第6个参数是代表角的水平直径和垂直直径的整数。

package mtk;

import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Graphics;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;

public class RectangleExample extends MIDlet {
private Display display;
private MyCanvas1 canvas;
public RectangleExample() {
display=Display.getDisplay(this);
canvas=new MyCanvas1(this);
}

protected void destroyApp(boolean arg0){
}

protected void pauseApp() {
}

protected void startApp() throws MIDletStateChangeException {
display.setCurrent(canvas);
}
public void exitMIDlet(){
destroyApp(true);
notifyDestroyed();
}
}

class MyCanvas1 extends Canvas implements CommandListener{
private Command CMD_EXIT=new Command("退出",Command.EXIT,1);
private RectangleExample rectangleExample;
public MyCanvas1(RectangleExample rectangleExample) {
this.rectangleExample=rectangleExample;
addCommand(CMD_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.drawRect(2, 2, 20, 20);
graphics.drawRoundRect(20, 20, 60, 60, 15, 45);
}
public void commandAction(Command c, Displayable d) {
if(c==CMD_EXIT){
rectangleExample.exitMIDlet();
}
}
}

 

颜色填充

package mtk;

import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Graphics;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;

public class FilledRectangleExample extends MIDlet {
private Display display;
private MyCanvas2 canvas;
public FilledRectangleExample() {
display=Display.getDisplay(this);
canvas=new MyCanvas2(this);
}

protected void destroyApp(boolean arg0){
}

protected void pauseApp() {
}

protected void startApp() throws MIDletStateChangeException {
display.setCurrent(canvas);
}
public void exitMIDlet(){
destroyApp(true);
notifyDestroyed();
}
}

class MyCanvas2 extends Canvas implements CommandListener{
private Command CMD_EXIT=new Command("退出",Command.EXIT,1);
private FilledRectangleExample rectangleExample;
public MyCanvas2(FilledRectangleExample rectangleExample) {
this.rectangleExample=rectangleExample;
addCommand(CMD_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.fillRect(2, 2, 20, 20);
graphics.fillRoundRect(20, 20, 60, 60, 15, 45);
}
public void commandAction(Command c, Displayable d) {
if(c==CMD_EXIT){
rectangleExample.exitMIDlet();
}
}
}