「java代码画线」java 画线
今天给各位分享java代码画线的知识，其中也会对java 画线进行解释，如果能碰巧解决你现在面临的问题，别忘了关注本站，现在开始吧！
本文目录一览：
- 1、java 如何在JPanel上画线
- 2、java 如何在jpanel上画垂直线、水平线、平行线？
- 3、java中在面板上怎么画直线？
- 4、用JAVA实现画线，不是直线，而是点住鼠标左键划到哪里哪里就画线，就
- 5、java简单的画线程序
- 6、java怎么画出一条直线呢？高手进吧。
java 如何在JPanel上画线
可以定义全局的变量来保存Graphics。
在组件处于可见的状态下使用getGraphics。代码如下：
import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class J extends JFrame implements KeyListener{
Graphics g=null;//全局变量
JPanel jp=new JPanel();
public J()
{
add(jp);
setSize(100, 100);
setVisible(true);//必须放在getGraphics之前
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
g=jp.getGraphics();
if(g==null)
{
System.out.println("NULL");
}
this.addKeyListener(this);
}
static public void main(String []agr){
new J();
}
@Override
public void keyPressed(KeyEvent e) {
// TODO Auto-generated method stub
System.out.println("draw");
g.drawLine(0, 0, 50, 50);
}
@Override
public void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub
}
@Override
public void keyTyped(KeyEvent e) {
// TODO Auto-generated method stub
}
}
java 如何在jpanel上画垂直线、水平线、平行线？
定义一个类继承JPanel类，重写 JPanel 的 paint 方法，使用 Graphics 绘制线段，如下代码：
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.JPanel;
class MyPanel extends JPanel {
@Override
public void paint(Graphics g) {
super.paint(g);
g.setColor(Color.RED);
for (int i = 0; i 10; i++) {
g.drawLine(10, 10 + i * 20, this.getWidth() - 10, 10 + i * 20);
}
for (int i = 0; i 10; i++) {
g.drawLine(10 + i * 20, 10, 10 + i * 20, this.getHeight() - 10);
}
}
}
public class App extends JFrame {
public App() {
this.setSize(400, 400);
this.setLocationRelativeTo(null);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
MyPanel panel = new MyPanel();
this.add(panel, BorderLayout.CENTER);
}
public static void main(String[] args) {
new App().setVisible(true);
}
}
运行结果：
java中在面板上怎么画直线？
方法1：
public static void main(String[] args) {
//JPanel p = new JPanel(); 注释掉这句
JFrame frame = new JFrame("DrawLine");
frame.add(new DrawLine());//将p对象换成本类
//因为本类继承了JPanel重写paintComponent进行绘制，是绘制到本类的panel上的，
//而不是绘制到new Panel()对象
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 200);
frame.setVisible(true);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawLine(50, 50, 200, 250);
}
方法2：
//这种方式可能 让你更理解
public static void main(String[] args) {
DrawLine dl = new DrawLine();//新建对象
dl.init();//执行初始化
}
private void init(){
//JPanel p = new JPanel(); 注释掉这句
JFrame frame = new JFrame("DrawLine");
frame.add(this);//将p对象换成本类
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 200);
frame.setVisible(true);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawLine(50, 50, 200, 250);
}
用JAVA实现画线，不是直线，而是点住鼠标左键划到哪里哪里就画线，就
import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Label;
import java.awt.Panel;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
public class MouseDrawPanel extends Frame
{
private static final long serialVersionUID = 1L;
MouseEvent e = null;
int startX = -1;
int startY = -1;
int endX = -1;
int endY = -1;
boolean left = false;
public MouseDrawPanel ( String title )
{
setTitle (title);
setLayout (new BorderLayout ());
setResizable (false);
setSize (500, 400);
setLocationRelativeTo (null);
addWindowListener (new WindowAdapter ()
{
@Override
public void windowClosing ( WindowEvent e )
{
System.exit (0);
}
});
}
@Override
public void paintComponents ( Graphics g )
{
float lineWidth = 8.0f;
( (Graphics2D) g ).setStroke (new BasicStroke (lineWidth));
g.setColor (Color.YELLOW);
g.drawLine (startX, startY, endX, endY);
g.dispose ();
}
public static void main ( String[] args )
{
final MouseDrawPanel mdp = new MouseDrawPanel ("Use Mouse Draw");
Panel panel = new Panel ();
panel.setLayout (new FlowLayout (FlowLayout.LEFT));
Label startL = new Label ("start: ");
Label endL = new Label ("end: ");
final Label nowL = new Label ("now: ");
final Label startR = new Label ("000,000");
final Label endR = new Label ("000,000");
final Label nowN = new Label ("000,000");
panel.add (startL);
panel.add (startR);
panel.add (endL);
panel.add (endR);
panel.add (nowL);
panel.add (nowN);
mdp.add (panel, "South");
mdp.addMouseMotionListener (new MouseMotionListener ()
{
@Override
public void mouseMoved ( MouseEvent e )
{
if (mdp.left)
{
nowN.setText (e.getX () + " , " + e.getY ());
}
}
@Override
public void mouseDragged ( MouseEvent e )
{
if (mdp.left)
{
mdp.endX = e.getX ();
mdp.endY = e.getY ();
mdp.paintComponents (mdp.getGraphics ());
mdp.startX = mdp.endX;
mdp.startY = mdp.endY;
endR.setText (mdp.endX + " , " + mdp.endY);
}
}
});
mdp.addMouseListener (new MouseAdapter ()
{
@Override
public void mousePressed ( MouseEvent e )
{
if (e.getButton () == MouseEvent.BUTTON1)
{
mdp.startX = e.getX ();
mdp.startY = e.getY ();
startR.setText (mdp.startX + " , " + mdp.startY);
mdp.left = true;
}
else
{
mdp.left = false;
}
}
@Override
public void mouseReleased ( MouseEvent e )
{
if (mdp.left)
{
endR.setText (e.getX () + " , " + e.getY ());
}
}
});
mdp.setVisible (true);
}
}
java简单的画线程序
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;public class DrawLine extends Frame
implements WindowListener
{
static ArrayList lbArray; DrawLine(){
setBounds(150,150,300,300);
setVisible(true);
Label lb0=new Label("Hello");
addWindowListener(this);
add(lb0);
lb0.setBounds(50,30,40,20);
Label lb1=new Label("World!");
add(lb1);
lb1.setBounds(50,90,40,20); Label lb2=new Label("Java");
add(lb2);
lb2.setBounds(50,150,40,20);
lbArray.add(lb0);
lbArray.add(lb1);
lbArray.add(lb2);
repaint(); }
public void windowClosed(WindowEvent w)
{
System.exit(0);
}
public void windowClosing(WindowEvent w)
{
dispose();
}
public void windowOpened(WindowEvent e) {}
public void windowIconified(WindowEvent e) {}
public void windowDeiconified(WindowEvent e) {}
public void windowActivated(WindowEvent e) {}
public void windowDeactivated(WindowEvent e) {}
public void paint(Graphics g)
{
super.paint(g); if(lbArray.size()=1)
{
g.setColor(Color.red);
int x1,y1,x2,y2;
Label lb=(Label)lbArray.get(0);
Rectangle rc=lb.getBounds();
x1=rc.x+rc.width/2;
y1=rc.y+rc.height/2;
for(int i=1;ilbArray.size();i++)
{
lb=(Label)lbArray.get(i);
rc=lb.getBounds();
x2=rc.x+rc.width/2;
y2=rc.y+rc.height/2;
g.drawLine(x1,y1,x2,y2);
x1=x2;
y1=y2;
}
}
} public static void main(String[] args){
lbArray=new ArrayList(10);
new DrawLine();
}
} 终于做了个满足你要求的东西。要知道我昨天和你说过我并不常用Java。赶快采纳吧。
java怎么画出一条直线呢？高手进吧。
我晕，组件要重绘，就使用paintComponent方法吧，没有什么灵活不灵活的
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import javax.swing.BorderFactory;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
public class FrameDemo extends JFrame {
private JPanel contentPane;
TestComponent tc1, tc2;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
FrameDemo frame = new FrameDemo();
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public FrameDemo() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 450, 300);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(new GridLayout(2, 1, 10, 10));
tc1 = new TestComponent();
tc1.setBorder(BorderFactory.createLineBorder(Color.BLUE));
tc2 = new TestComponent();
tc2.setBorder(BorderFactory.createLineBorder(Color.PINK));
contentPane.add(tc1);
contentPane.add(tc2);
}
}
class TestComponent extends JComponent {
public void paintComponent(Graphics g1) {
Graphics2D g = (Graphics2D) g1;
g.setColor(Color.RED);
g.drawLine(0, 0, this.getWidth(), this.getHeight());
}
}
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