为什么可以';我不能用java在框架上画东西吗?
编码在这里。 我无法在框架内创建任何矩形或圆形。 本项目的目标是创建转换celcius 2 Farenheit和Farenheit 2 celcius 所以我想要的是,请教我如何在框架的侧面画矩形或椭圆形为什么可以';我不能用java在框架上画东西吗?,java,swing,jframe,paint,Java,Swing,Jframe,Paint,编码在这里。 我无法在框架内创建任何矩形或圆形。 本项目的目标是创建转换celcius 2 Farenheit和Farenheit 2 celcius 所以我想要的是,请教我如何在框架的侧面画矩形或椭圆形 import java.awt.BorderLayout; import java.awt.Color; import java.awt.Container; import java.awt.Frame; import java.awt.Graphics; import java.awt.Gr
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class C2F extends JComponent{
private double input1, output1;
private double input2, output2;
JPanel center = new JPanel();
JPanel top = new JPanel();
JPanel east = new JPanel();
JPanel south = new JPanel();
//for giving input & output
C2F(){
JFrame frame = new JFrame();
frame.setTitle("C2F");
frame.setSize(700,500);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.getContentPane().add(top,BorderLayout.NORTH);
frame.getContentPane().add(center,BorderLayout.CENTER);
frame.getContentPane().add(south,BorderLayout.SOUTH);
frame.getContentPane().add(east,BorderLayout.EAST);
frame.setVisible(true);
CC2F();
}
public void CC2F(){
//making frame
//give specific location
JLabel L1 = new JLabel("Please input Celcius or Fahrenheit to Convert");
top.add(L1);
JLabel l1 = new JLabel("Cel -> Fah");
south.add(l1);
JTextField T1 = new JTextField(12);
south.add(T1);
JButton B1 = new JButton("Convert");
south.add(B1);
JLabel l2 = new JLabel("Fah -> Cel");
south.add(l2);
JTextField T2 = new JTextField(12);
south.add(T2);
JButton B2 = new JButton("Convert");
south.add(B2);
//to create buttons and labels to give an answer
B1.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
input1 = Double.parseDouble(T1.getText());
output1 = input1 *(9/5) + 32;
T2.setText(""+output1);
repaint();
}
});
B2.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
input2 = Double.parseDouble(T2.getText());
output2 = (input2 - 32)/9*5;
T1.setText(""+output2);
}
});
//making events
//placing the buttons and labels
output1 = 0;
output2 = 0;
//initialize the value
}
public void paintComponent(Graphics g) {
//error spots. it compiles well. But this is not what I want.
super.paintComponent(g);
Graphics2D gg = (Graphics2D) g;
gg.setColor(Color.BLACK);
gg.drawOval(350, 500,12,12);
gg.setColor(Color.RED);
gg.fillRect(350, 500, 10,(int) output1);
gg.fillOval(350, 500, 10, 10);
gg.setColor(Color.RED);
gg.fillRect(350, 500, 10,(int) output2);
gg.fillOval(350, 500, 10, 10);
//to draw stuffs
}
public static void main(String[] args)
{//to run the program
new C2F();
}
}
C2F
,因此您的paint
方法将永远不会被调用paintComponent
,而不是paint
,因为您已经破坏了组件的绘制链,这可能会导致无休止的问题,出现奇妙而有趣的绘制故障。约定还建议您在执行任何自定义绘制之前调用super.paintComponent
(当重写paintComponent
时)谢谢你回答我的问题,但我不明白。调用super.paintComponent是什么意思?你能给我举个例子吗?而且还是不行。即使我用超级油漆组件。。我想我没有。那么你的意思是我需要创建另一个方法来创建框架吗?我用另一种方法来代替构造器。那我该怎么办?我应该把super.paintComponent放在哪里?
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.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class C2F extends JComponent {
public C2F() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
TestPane center = new TestPane();
JPanel top = new JPanel();
JPanel east = new JPanel();
JPanel south = new JPanel();
//give specific location
JLabel L1 = new JLabel("Please input Celcius or Fahrenheit to Convert");
top.add(L1);
JLabel l1 = new JLabel("Cel -> Fah");
south.add(l1);
JTextField T1 = new JTextField(12);
south.add(T1);
JButton B1 = new JButton("Convert");
south.add(B1);
JLabel l2 = new JLabel("Fah -> Cel");
south.add(l2);
JTextField T2 = new JTextField(12);
south.add(T2);
JButton B2 = new JButton("Convert");
south.add(B2);
//to create buttons and labels to give an answer
B1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
double input1 = Double.parseDouble(T1.getText());
double output1 = input1 * (9 / 5) + 32;
T2.setText("" + output1);
center.setOutput1(output1);
}
});
B2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
double input2 = Double.parseDouble(T2.getText());
double output2 = (input2 - 32) / 9 * 5;
T1.setText("" + output2);
center.setOutput2(output2);
}
});
//making events
frame.getContentPane().add(top, BorderLayout.NORTH);
frame.getContentPane().add(center, BorderLayout.CENTER);
frame.getContentPane().add(south, BorderLayout.SOUTH);
frame.getContentPane().add(east, BorderLayout.EAST);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private double output1, output2;
public TestPane() {
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 600);
}
public void setOutput1(double output1) {
this.output1 = output1;
repaint();
}
public void setOutput2(double output2) {
this.output2 = output2;
repaint();
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
g2d.setColor(Color.BLACK);
g2d.drawOval(350, 500, 12, 12);
g2d.setColor(Color.RED);
g2d.fillRect(350, 0, 10, (int) output1);
g2d.fillOval(350, 0, 10, 10);
g2d.setColor(Color.BLUE);
g2d.fillRect(350, 0, 10, (int) output2);
g2d.fillOval(350, 0, 10, 10);
g2d.dispose();
}
}
public static void main(String[] args) {//to run the program
new C2F();
}
}