在 Java 中单击按钮在 JPanel 中画一条线 [英] Draw a line in a JPanel with button click in Java
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问题描述
我想在 JPanel 中画一条线.这是我的 GUI，我希望在 JPanel 中有一条白色的线.
I want to draw a line in a JPanel. This is my GUI and I want a line in the JPanel in white.
我找到了很多例子，但问题是如何使用它.
I find many examples but the problem is the how to use it.
在许多示例中，它们总是在从 JPanel 扩展的 JFrame 中绘制.
In many exmples, always they draw in a JFrame that extends from a JPanel.
我想将面板添加到框架并添加一些按钮以在多个方向绘制线条并使用中心的 X 按钮清洁 JPanel.
I want to add the Panel to the Frame and add some buttons to draw lines in many directions and use the X button in center to clean the JPanel.
这是界面的代码:
import java.awt.BorderLayout;
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import java.awt.Color;
import javax.swing.JScrollPane;
import javax.swing.JLabel;
import javax.swing.ImageIcon;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
public class circuit extends JFrame {
private JPanel contentPane;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
circuit frame = new circuit();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the frame.
*/
public circuit() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 559, 332);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(null);
JScrollPane scrollPane = new JScrollPane();
scrollPane.setBounds(10, 21, 359, 255);
contentPane.add(scrollPane);
JPanel panel = new JPanel();
scrollPane.setViewportView(panel);
panel.setBackground(Color.WHITE);
JLabel label = new JLabel("New label");
label.addMouseListener(new MouseAdapter() {
@Override
public void mouseClicked(MouseEvent arg0) {
/////////////
}
});
label.setIcon(new ImageIcon("C:\Users\achermen\Desktop\up.png"));
label.setBounds(447, 66, 46, 48);
contentPane.add(label);
JLabel label_1 = new JLabel("New label");
label_1.setIcon(new ImageIcon("C:\Users\achermen\Desktop\down.png"));
label_1.setBounds(447, 159, 46, 48);
contentPane.add(label_1);
JLabel label_2 = new JLabel("New label");
label_2.setIcon(new ImageIcon("C:\Users\achermen\Desktop\right.png"));
label_2.setBounds(495, 112, 46, 48);
contentPane.add(label_2);
JLabel label_3 = new JLabel("New label");
label_3.setIcon(new ImageIcon("C:\Users\achermen\Desktop\left.png"));
label_3.setBounds(398, 112, 46, 48);
contentPane.add(label_3);
JLabel label_4 = new JLabel("New label");
label_4.setIcon(new ImageIcon("C:\Users\achermen\Desktop\1303860240_list-remove.png"));
label_4.setBounds(447, 112, 46, 48);
contentPane.add(label_4);
}
}
这是画线的代码
public void paint(Graphics graphics)
{
graphics.drawLine(10, 20, 300, 310);
}
那么如何使用这行....
So how to use this lines ....
提前致谢.
最好的问候，
阿里
推荐答案
使用以下方法画线可能更容易:
It may be easier to draw lines using the following approach:
- 单击以标记第一个端点
- 拖动以显示正在进行的行
- 释放以标记第二个端点
这个相关的示例可能会提供一些额外的指导.
This related example may offer some additional guidance.
- The example below implements the outline above.
- I've update the example to show how to use a panel of buttons to affect the drawing.
- See also this related example that uses the
Actioninterface with key bindings. - I've updated this example to use Key Bindings.
LinePanel.java
import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.AbstractAction;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
/**
* @see https://stackoverflow.com/questions/6991648
* @see https://stackoverflow.com/questions/6887296
* @see https://stackoverflow.com/questions/5797965
*/
public class LinePanel extends JPanel {
private MouseHandler mouseHandler = new MouseHandler();
private Point p1 = new Point(100, 100);
private Point p2 = new Point(540, 380);
private boolean drawing;
public LinePanel() {
this.setPreferredSize(new Dimension(640, 480));
this.addMouseListener(mouseHandler);
this.addMouseMotionListener(mouseHandler);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
g2d.setColor(Color.blue);
g2d.setRenderingHint(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setStroke(new BasicStroke(8,
BasicStroke.CAP_ROUND, BasicStroke.JOIN_BEVEL));
g.drawLine(p1.x, p1.y, p2.x, p2.y);
}
private class MouseHandler extends MouseAdapter {
@Override
public void mousePressed(MouseEvent e) {
drawing = true;
p1 = e.getPoint();
p2 = p1;
repaint();
}
@Override
public void mouseReleased(MouseEvent e) {
drawing = false;
p2 = e.getPoint();
repaint();
}
@Override
public void mouseDragged(MouseEvent e) {
if (drawing) {
p2 = e.getPoint();
repaint();
}
}
}
private class ControlPanel extends JPanel {
private static final int DELTA = 10;
public ControlPanel() {
this.add(new MoveButton("u2190", KeyEvent.VK_LEFT, -DELTA, 0));
this.add(new MoveButton("u2191", KeyEvent.VK_UP, 0, -DELTA));
this.add(new MoveButton("u2192", KeyEvent.VK_RIGHT, DELTA, 0));
this.add(new MoveButton("u2193", KeyEvent.VK_DOWN, 0, DELTA));
}
private class MoveButton extends JButton {
KeyStroke k;
int dx, dy;
public MoveButton(String name, int code,
final int dx, final int dy) {
super(name);
this.k = KeyStroke.getKeyStroke(code, 0);
this.dx = dx;
this.dy = dy;
this.setAction(new AbstractAction(this.getText()) {
@Override
public void actionPerformed(ActionEvent e) {
LinePanel.this.p1.translate(dx, dy);
LinePanel.this.p2.translate(dx, dy);
LinePanel.this.repaint();
}
});
ControlPanel.this.getInputMap(WHEN_IN_FOCUSED_WINDOW)
.put(k, k.toString());
ControlPanel.this.getActionMap()
.put(k.toString(), new AbstractAction() {
@Override
public void actionPerformed(ActionEvent e) {
MoveButton.this.doClick();
}
});
}
}
}
private void display() {
JFrame f = new JFrame("LinePanel");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(this);
f.add(new ControlPanel(), BorderLayout.SOUTH);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
new LinePanel().display();
}
});
}
}
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