标签:java swing jpanel awt mouseevent
我用Java编写了以下微绘画程序:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
class AuxClass1 extends JFrame implements MouseListener, MouseMotionListener{
private JPanel panel1 = new JPanel();
private JPanel panel2 = new JPanel();
private JLabel label1_x = new JLabel();
private JLabel label1_y = new JLabel();
private JLabel label1_x_info = new JLabel("");
private JLabel label1_y_info = new JLabel("");
//add a container keep panels with widgets
private Container con1 = getContentPane();
private int xval1;
private int yval1;
private GridLayout layout1 = new GridLayout(2,2,2,2);
private JOptionPane info1 = new JOptionPane();
//get the class that controls the mouse
public AuxClass1(){
super("Mouse Experiment");
panel1.setBackground(Color.WHITE);
panel1.setLayout(layout1);
label1_x.setText("X Location");
label1_x.setBorder(BorderFactory.createLineBorder(Color.BLUE, 2));
label1_y.setBorder(BorderFactory.createLineBorder(Color.BLUE, 2));
label1_x_info.setBorder(BorderFactory.createLineBorder(Color.RED, 2));
label1_y_info.setBorder(BorderFactory.createLineBorder(Color.RED, 2));
label1_y.setText("Y Location");
panel1.add(label1_x);
panel1.add(label1_y);
panel1.add(label1_x_info);
panel1.add(label1_y_info);
con1.add(panel1, BorderLayout.NORTH);
panel2.setBackground(new Color(100,200,200));
panel2.setBorder(BorderFactory.createLineBorder(new Color(255,255,0), 2));
panel2.addMouseListener(this);
panel2.addMouseMotionListener(this);
con1.add(panel2, BorderLayout.CENTER);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(500, 500);
setLocationRelativeTo(null);
setVisible(true);
}
@Override
public void mouseClicked(MouseEvent arg0) {
}
@Override
public void mouseMoved(MouseEvent arg0) {
// TODO Auto-generated method stub
if (arg0.getSource()==panel2){
x_var = arg0.getX();
y_var = arg0.getY();
label1_x_info.setText(Integer.toString(x_var));
label1_y_info.setText(Integer.toString(y_var));
}
}
@Override
public void mouseDragged(MouseEvent e) {
// TODO Auto-generated method stub
if (e.getSource()==panel2){
//info1.showMessageDialog(this, "This is an awesome Mouse toolbox!");
xval1 = e.getX();
yval1= e.getY();
AuxClass2 Inst2 = new AuxClass2(xval1, yval1);
Inst2.paintComponent(getGraphics());
}
}
@Override
public void mouseEntered(MouseEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void mouseExited(MouseEvent arg0) {
if (arg0.getSource()==panel2){
label1_x_info.setText("");
label1_y_info.setText("");
}
// TODO Auto-generated method stub
}
@Override
public void mousePressed(MouseEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void mouseReleased(MouseEvent arg0) {
// TODO Auto-generated method stub
}
}
class AuxClass2 extends JPanel{
//JOptionPane info2 = new JOptionPane();
private int xval2;
private int yval2;
public AuxClass2(int input1, int input2){
xval2 = input1;
yval2 = input2;
setSize(500,500);
}
@Override
public void paintComponent(Graphics g){
super.paintComponents(g);
g.setColor(Color.BLUE);
g.fillRect(xval2, yval2+70, 5, 5);
}
}
public class MainClass{
private static AuxClass1 Inst1;
public static void main(String args[]){
Inst1 = new AuxClass1();
}
}
除了mouseDragged方法的Y坐标之外,它的工作正常(请参阅类t3_aux2中的paintComponent方法).由于某种原因,该方法使用的Y坐标比panel2中的实际坐标小约70个像素.我怀疑这与t3_aux2类中继承的JPanel方法有关,但不太确定.
如果有人能澄清这一点,那就太酷了.谢谢.
UPD:如果有人提出如何改进风格和/或优化代码的建议,那也将受到大力赞赏.
UPD2:更改名称以符合Java命名约定.
解决方法:
我试过你的代码.我认为您的问题来自于使用t3_aux2坐标在t3_aux1上绘制的事实.我会尝试确认一下,然后我回到这里……
编辑:好的,就是这样.
在t3_aux1构造函数中,如果你写的话
System.out.println("panel1 height = " + panel1.getHeight());
System.out.println("label1 height = " + label1_x.getHeight())
它打印
panel1 height = 42
label1 height = 20
所以你的偏移是42 20 4 * 2 = 70
4 * 2来自您的线条边框,厚度为2.
由于可以计算精确的偏移量,因此您可以动态修复它.
编辑2:
事实上,您使用的坐标来自panel2,因为mouseListener附加到panel2.但是您可以使用JFrame Graphics,而不是使用panel2图形.
写这个应该解决你的坐标问题.
inst2.paintComponent(panel2.getGraphics());
但正如Kleopatra所说,你并没有以正确的方式做到这一点.你永远不应该调用getGraphics()或paintComponent().我认为你应该考虑使用java.awt.Canvas作为你的“panel2”对象的超类.
还有一个建议:请注意,您的图纸不会被记忆,因此,如果您缩小窗口或将其隐藏在另一个窗口后面,所绘制的所有内容都将丢失.
标签:java,swing,jpanel,awt,mouseevent 来源: https://codeday.me/bug/20190620/1248220.html
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