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使用java畫圓要用到繪圖類Graphics,下面是實(shí)例代碼和運(yùn)行效果:
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package?com.dikea.demo01;
import?java.awt.*;
import?javax.swing.*;
//?java繪圖原理
public?class?demo_01??extends?JFrame?{
MyPanel?mp?=?null;
public?static?void?main(String[]?args)?{
//?TODO?自動(dòng)生成的方法存根
demo_01?demo01?=?new?demo_01();
}
public?demo_01(){
mp?=?new?MyPanel();
this.add(mp);
this.setSize(400,?300);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setVisible(true);
}
}
//?定義一個(gè)MyPanel面板,用于繪圖區(qū)域
class?MyPanel?extends?JPanel{
//覆蓋JPanel
//?Graphics?是繪圖的重要類,可以理解成一支畫筆
public?void?paint(Graphics?g){
//??1.?調(diào)用父類函數(shù)完成初始化任務(wù)
//??這句話不可以少
super.paint(g);
//?先畫出一個(gè)圓圈
g.drawOval(100,?100,?30,?30);
}
}
代碼復(fù)制進(jìn)ide編程工具,運(yùn)行效果如下:
新建一個(gè)java文件,取名叫做PaintJava.java
代碼如下:
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import java.awt.geom.*;
import java.io.*;
class Point implements Serializable
{
int x,y;
Color col;
int tool;
int boarder;
Point(int x, int y, Color col, int tool, int boarder)
{
this.x = x;
this.y = y;
this.col = col;
this.tool = tool;
this.boarder = boarder;
}
}
class paintboard extends Frame implements ActionListener,MouseMotionListener,MouseListener,ItemListener
{
int x = -1, y = -1;
int con = 1;//畫筆大小
int Econ = 5;//橡皮大小
int toolFlag = 0;//toolFlag:工具標(biāo)記
//toolFlag工具對(duì)應(yīng)表:
//(0--畫筆);(1--橡皮);(2--清除);
//(3--直線);(4--圓);(5--矩形);
Color c = new Color(0,0,0); //畫筆顏色
BasicStroke size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);//畫筆粗細(xì)
Point cutflag = new Point(-1, -1, c, 6, con);//截?cái)鄻?biāo)志
Vector paintInfo = null;//點(diǎn)信息向量組
int n = 1;
FileInputStream picIn = null;
FileOutputStream picOut = null;
ObjectInputStream VIn = null;
ObjectOutputStream VOut = null;
// *工具面板--畫筆,直線,圓,矩形,多邊形,橡皮,清除*/
Panel toolPanel;
Button eraser, drLine,drCircle,drRect;
Button clear ,pen;
Choice ColChoice,SizeChoice,EraserChoice;
Button colchooser;
Label 顏色,大小B,大小E;
//保存功能
Button openPic,savePic;
FileDialog openPicture,savePicture;
paintboard(String s)
{
super(s);
addMouseMotionListener(this);
addMouseListener(this);
paintInfo = new Vector();
/*各工具按鈕及選擇項(xiàng)*/
//顏色選擇
ColChoice = new Choice();
ColChoice.add("black");
ColChoice.add("red");
ColChoice.add("blue");
ColChoice.add("green");
ColChoice.addItemListener(this);
//畫筆大小選擇
SizeChoice = new Choice();
SizeChoice.add("1");
SizeChoice.add("3");
SizeChoice.add("5");
SizeChoice.add("7");
SizeChoice.add("9");
SizeChoice.addItemListener(this);
//橡皮大小選擇
EraserChoice = new Choice();
EraserChoice.add("5");
EraserChoice.add("9");
EraserChoice.add("13");
EraserChoice.add("17");
EraserChoice.addItemListener(this);
////////////////////////////////////////////////////
toolPanel = new Panel();
clear = new Button("清除");
eraser = new Button("橡皮");
pen = new Button("畫筆");
drLine = new Button("畫直線");
drCircle = new Button("畫圓形");
drRect = new Button("畫矩形");
openPic = new Button("打開(kāi)圖畫");
savePic = new Button("保存圖畫");
colchooser = new Button("顯示調(diào)色板");
//各組件事件監(jiān)聽(tīng)
clear.addActionListener(this);
eraser.addActionListener(this);
pen.addActionListener(this);
drLine.addActionListener(this);
drCircle.addActionListener(this);
drRect.addActionListener(this);
openPic.addActionListener(this);
savePic.addActionListener(this);
colchooser.addActionListener(this);
顏色 = new Label("畫筆顏色",Label.CENTER);
大小B = new Label("畫筆大小",Label.CENTER);
大小E = new Label("橡皮大小",Label.CENTER);
//面板添加組件
toolPanel.add(openPic);
toolPanel.add(savePic);
toolPanel.add(pen);
toolPanel.add(drLine);
toolPanel.add(drCircle);
toolPanel.add(drRect);
toolPanel.add(顏色); toolPanel.add(ColChoice);
toolPanel.add(大小B); toolPanel.add(SizeChoice);
toolPanel.add(colchooser);
toolPanel.add(eraser);
toolPanel.add(大小E); toolPanel.add(EraserChoice);
toolPanel.add(clear);
//工具面板到APPLET面板
add(toolPanel,BorderLayout.NORTH);
setBounds(60,60,900,600); setVisible(true);
validate();
//dialog for save and load
openPicture = new FileDialog(this,"打開(kāi)圖畫",FileDialog.LOAD);
openPicture.setVisible(false);
savePicture = new FileDialog(this,"保存圖畫",FileDialog.SAVE);
savePicture.setVisible(false);
openPicture.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{ openPicture.setVisible(false); }
});
savePicture.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{ savePicture.setVisible(false); }
});
addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{ System.exit(0);}
});
}
public void paint(Graphics g)
{
Graphics2D g2d = (Graphics2D)g;
Point p1,p2;
n = paintInfo.size();
if(toolFlag==2)
g.clearRect(0,0,getSize().width,getSize().height);//清除
for(int i=0; in ;i++){
p1 = (Point)paintInfo.elementAt(i);
p2 = (Point)paintInfo.elementAt(i+1);
size = new BasicStroke(p1.boarder,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
g2d.setColor(p1.col);
g2d.setStroke(size);
if(p1.tool==p2.tool)
{
switch(p1.tool)
{
case 0://畫筆
Line2D line1 = new Line2D.Double(p1.x, p1.y, p2.x, p2.y);
g2d.draw(line1);
break;
case 1://橡皮
g.clearRect(p1.x, p1.y, p1.boarder, p1.boarder);
break;
case 3://畫直線
Line2D line2 = new Line2D.Double(p1.x, p1.y, p2.x, p2.y);
g2d.draw(line2);
break;
case 4://畫圓
Ellipse2D ellipse = new Ellipse2D.Double(p1.x, p1.y, Math.abs(p2.x-p1.x) , Math.abs(p2.y-p1.y));
g2d.draw(ellipse);
break;
case 5://畫矩形
Rectangle2D rect = new Rectangle2D.Double(p1.x, p1.y, Math.abs(p2.x-p1.x) , Math.abs(p2.y-p1.y));
g2d.draw(rect);
break;
case 6://截?cái)?,跳過(guò)
i=i+1;
break;
default :
}//end switch
}//end if
}//end for
}
public void itemStateChanged(ItemEvent e)
{
if(e.getSource()==ColChoice)//預(yù)選顏色
{
String name = ColChoice.getSelectedItem();
if(name=="black")
{c = new Color(0,0,0); }
else if(name=="red")
{c = new Color(255,0,0);}
else if(name=="green")
{c = new Color(0,255,0);}
else if(name=="blue")
{c = new Color(0,0,255);}
}
else if(e.getSource()==SizeChoice)//畫筆大小
{
String selected = SizeChoice.getSelectedItem();
if(selected=="1")
{
con = 1;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
else if(selected=="3")
{
con = 3;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
else if(selected=="5")
{con = 5;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
else if(selected=="7")
{con = 7;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
else if(selected=="9")
{con = 9;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
}
else if(e.getSource()==EraserChoice)//橡皮大小
{
String Esize = EraserChoice.getSelectedItem();
if(Esize=="5")
{ Econ = 5*2; }
else if(Esize=="9")
{ Econ = 9*2; }
else if(Esize=="13")
{ Econ = 13*2; }
else if(Esize=="17")
{ Econ = 17*3; }
}
}
public void mouseDragged(MouseEvent e)
{
Point p1 ;
switch(toolFlag){
case 0://畫筆
x = (int)e.getX();
y = (int)e.getY();
p1 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p1);
repaint();
break;
case 1://橡皮
x = (int)e.getX();
y = (int)e.getY();
p1 = new Point(x, y, null, toolFlag, Econ);
paintInfo.addElement(p1);
repaint();
break;
default :
}
}
public void mouseMoved(MouseEvent e) {}
public void update(Graphics g)
{
paint(g);
}
public void mousePressed(MouseEvent e)
{
Point p2;
switch(toolFlag){
case 3://直線
x = (int)e.getX();
y = (int)e.getY();
p2 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p2);
break;
case 4: //圓
x = (int)e.getX();
y = (int)e.getY();
p2 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p2);
break;
case 5: //矩形
x = (int)e.getX();
y = (int)e.getY();
p2 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p2);
break;
default :
}
}
public void mouseReleased(MouseEvent e)
{
Point p3;
switch(toolFlag){
case 0://畫筆
paintInfo.addElement(cutflag);
break;
case 1: //eraser
paintInfo.addElement(cutflag);
break;
case 3://直線
x = (int)e.getX();
y = (int)e.getY();
p3 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p3);
paintInfo.addElement(cutflag);
repaint();
break;
case 4: //圓
x = (int)e.getX();
y = (int)e.getY();
p3 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p3);
paintInfo.addElement(cutflag);
repaint();
break;
case 5: //矩形
x = (int)e.getX();
y = (int)e.getY();
p3 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p3);
paintInfo.addElement(cutflag);
repaint();
break;
default:
}
}
public void mouseEntered(MouseEvent e){}
public void mouseExited(MouseEvent e){}
public void mouseClicked(MouseEvent e){}
public void actionPerformed(ActionEvent e)
{
if(e.getSource()==pen)//畫筆
{toolFlag = 0;}
if(e.getSource()==eraser)//橡皮
{toolFlag = 1;}
if(e.getSource()==clear)//清除
{
toolFlag = 2;
paintInfo.removeAllElements();
repaint();
}
if(e.getSource()==drLine)//畫線
{toolFlag = 3;}
if(e.getSource()==drCircle)//畫圓
{toolFlag = 4;}
if(e.getSource()==drRect)//畫矩形
{toolFlag = 5;}
if(e.getSource()==colchooser)//調(diào)色板
{
Color newColor = JColorChooser.showDialog(this,"調(diào)色板",c);
c = newColor;
}
if(e.getSource()==openPic)//打開(kāi)圖畫
{
openPicture.setVisible(true);
if(openPicture.getFile()!=null)
{
int tempflag;
tempflag = toolFlag;
toolFlag = 2 ;
repaint();
try{
paintInfo.removeAllElements();
File filein = new File(openPicture.getDirectory(),openPicture.getFile());
picIn = new FileInputStream(filein);
VIn = new ObjectInputStream(picIn);
paintInfo = (Vector)VIn.readObject();
VIn.close();
repaint();
toolFlag = tempflag;
}
catch(ClassNotFoundException IOe2)
{
repaint();
toolFlag = tempflag;
System.out.println("can not read object");
}
catch(IOException IOe)
{
repaint();
toolFlag = tempflag;
System.out.println("can not read file");
}
}
}
if(e.getSource()==savePic)//保存圖畫
{
savePicture.setVisible(true);
try{
File fileout = new File(savePicture.getDirectory(),savePicture.getFile());
picOut = new FileOutputStream(fileout);
VOut = new ObjectOutputStream(picOut);
VOut.writeObject(paintInfo);
VOut.close();
}
catch(IOException IOe)
{
System.out.println("can not write object");
}
}
}
}//end paintboard
public class PaintJava
{
public static void main(String args[])
{ new paintboard("畫圖程序"); }
}
累啊..給分吧...!!
幫你改了一下。
你要畫在panel上,然后frame.add(panel)就能顯示。
是不是和applet搞混了,applet復(fù)寫一些方法就能顯示,但現(xiàn)在你編的是java gui
import java.awt.*;
import java.awt.Event.*;
import javax.swing.*; //import javax.swing.Timer;
import java.awt.BasicStroke;
//import java.util.Date;
//import java.text.*;
//import java.util.*;
public class TestGui {
public void paint(Graphics g) {
Graphics2D a2d = (Graphics2D) g;
int x = 120, y = 90, width = 150, height = 150;
a2d.setColor(Color.red);
a2d.setStroke(new BasicStroke(3.0f)); // 設(shè)置線條寬度,3.0即線的寬度
a2d.drawOval(x, y, width, height);
}
public static void main(String[] args) {
JFrame frame = new JFrame();
// frame.add(new paint(),BorderLayout.CENTER);
frame.setSize(500, 500);
frame.setLocation(200, 200);
frame.setVisible(true);
Panel p = new Panel();
frame.add(p);
// frame.paint(null);
// TODO code application logic here
}
}
class Panel extends JPanel {
// 重新覆蓋paint方法
public void paint(Graphics g) {
super.paint(g);
Graphics2D a2d = (Graphics2D) g;
int x = 120, y = 90, width = 150, height = 150;
a2d.setColor(Color.red);
a2d.setStroke(new BasicStroke(3.0f)); // 設(shè)置線條寬度,3.0即線的寬度
a2d.drawOval(x, y, width, height);
}
}
首先,手動(dòng)畫一個(gè)小烏龜,如下:
然后,按照J(rèn)ava繪圖基本步驟一步步來(lái)。
swing 編程步驟:
1. 繼承JFrame
2. 定義組件
3.創(chuàng)建組件(構(gòu)造函數(shù))
4.添加組件
5.對(duì)窗體設(shè)置
6.顯示窗體
最終效果如下:
代碼如下:
/**?
*?功能:畫一個(gè)烏龜?
*/??
package?com.test1;??
import?java.awt.*;??
import?javax.swing.*;??
public?class?MyTortoise??extends?JFrame{??
MyPanel2?mp?=?null;??
//構(gòu)造函數(shù)??
public?MyTortoise(){??
mp?=?new?MyPanel2();??
this.add(mp);??
this.setTitle("小烏龜,丑丑噠");??
this.setSize(400,300);??
this.setVisible(true);??
this.setLocation(300,200);??
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);??
}??
public?static?void?main(String[]?args)?{??
MyTortoise?mtg?=?new?MyTortoise();??
}?????
}??
//我的面板。只有JPanel有畫圖方法,JFrame沒(méi)有,故必須在JFrame中添加JPanel??
class?MyPanel2?extends?JPanel{??
//定義一個(gè)烏龜??
Tortoise?t?=?null;??
//構(gòu)造函數(shù)??
public?MyPanel2(){????
t?=?new??Tortoise(100,100);??
}??
//畫烏龜??
public?void?drawTortoise(int?x,?int?y,?Graphics?g){??
//1.畫臉??
g.setColor(Color.green);??
g.fillOval(x+60,?y,?30,?15);??
//2.畫左眼??
g.setColor(Color.black);??
g.fillOval(x+65,?y+3,?5,?5);??
//3.畫右眼??
g.fillOval(x+78,?y+3,?5,?5);??
//4.畫脖子??
g.setColor(Color.green);??
g.fillOval(x+70,?y,?10,?42);??
//5.畫烏龜殼??
g.setColor(Color.red);??
g.fillOval(x+40,?y+40,?70,?100);??
//6.畫左上腳??
g.setColor(Color.green);??
g.fillOval(x+15,?y+60,?30,?10);??
//7.畫右上腳??
g.fillOval(x+105,?y+60,?30,?10);??
//8.畫左下腳??
g.fillOval(x+15,?y+110,?30,?10);??
//9.畫右下腳??
g.fillOval(x+105,?y+110,?30,?10);??
//10.畫尾巴??
g.setColor(Color.black);??
g.drawLine(x+70,y+140,x+130,y+210);??
g.drawOval(x+95,?y+150,?30,?30);??
}??
//覆蓋JPanel的paint方法??
//Graphics?是繪圖的重要類。你可以把他理解成一只畫筆??
public?void?paint(Graphics?g){??
//1.調(diào)用父類函數(shù)完成初始化任務(wù)??
//這句話不能少??
super.paint(g);??
//2.畫烏龜,調(diào)用方法即可??
this.drawTortoise(50,?50,?g);??
}??
}??
//定義一個(gè)烏龜類??
class?Tortoise?{??
//表示烏龜?shù)臋M坐標(biāo)??
int?x?=?0;??
//表示烏龜?shù)目v坐標(biāo)??
int?y?=?0;??
public?int?getX()?{??
return?x;??
}??
public?void?setX(int?x)?{??
this.x?=?x;??
}??
public?int?getY()?{??
return?y;??
}??
public?void?setY(int?y)?{??
this.y?=?y;??
}??
public?Tortoise(int?x,?int?y){??
this.x?=?x;??
this.y?=?y;??
}??
}
java五角星用代碼打印出來(lái),主要是使用system.print函數(shù),代碼如下:
class kongzhitao{
public static void main(String[] args){
String[] wujiaoxing={" *"," * *","* * * *"," * *"," * *"," * * * *","* *"};
for(int i=0;i System.out.println(wujiaoxing[i]);
}
}
}
java在JFrame上畫東西,主要是使用paint方法,代碼如下:
import?java.awt.Color;
import?java.awt.Graphics;
import?javax.swing.JFrame;
import?javax.swing.JPanel;
public?class?Draw?extends?JFrame{
JPanel??jPanel=new?JPanel();
public?Draw()?{
jPanel.setBackground(Color.red);
add(jPanel);?
Drawation?drawaction=new?Drawation();//添加畫圖,把上面jpanel的設(shè)置給覆蓋了;要是先添加畫圖再添加
add(drawaction);????????????????????//jpanel則把畫圖覆蓋了
}
public?static?void?main(String[]?args){
Draw?draw=new?Draw();
draw.setTitle("abc");
draw.setSize(300,300);
draw.setVisible(true);
draw.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
class?Drawation?extends?JPanel{
public?void?paintComponent(Graphics?g){
super.paintComponents(g);
g.drawString("agagh",?50,?45);
}
}
運(yùn)行結(jié)果如下: