我想要做的是,一旦我按下“GO”按钮,它将绘制/绘制 3 个具有不同坐标的椭圆形。我尝试过重新喷漆,但似乎不起作用。它只显示一个椭圆,即最后一个椭圆。我希望它堆叠起来并附加椭圆形。
这是我的代码:
import javax.swing.*;
import java.awt.Graphics;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class Test extends JFrame implements ActionListener{
JButton button;
int[] itoken;
int x,y;
public Test() {
super("Test");
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setSize(600,500);
this.setVisible(true);
this.setResizable(true);
this.setLayout(null);
button= new JButton("GO");
button.setBounds(500, 100, 50,50);
this.add(button);
button.addActionListener(this);
}
public void actionPerformed(ActionEvent e){
if(e.getSource()==button){
String text= "200 300 250 150 400 100";
String[] token= text.split("\\W");
itoken= new int[token.length];
int i=0;
for (String str : token){
itoken[i++] = Integer.parseInt(str);
}
for(i=0; i<itoken.length; i++)
System.out.println(itoken[i]);
run();
}
}
public void paint(Graphics g) {
super.paint(g);
g.drawOval(x - 5, y - 5, 10, 10);
}
public void run(){
int i=0;
while(i<itoken.length-1){
repaint();
x=itoken[i];
y=itoken[i+1];
i++;
}
}
public static void main(String[] args) {
Test test = new Test();
}
}
最佳答案
Note - I was working on this answer right before you deleted your previous question, so the answer may see a little off in terms of the new code you posted in this question, but it gets you towards the same goal.
不要初始化
actionPerformed
中的所有内容。您将获得NullPointerException
因为paint
在初始化数组之前由框架隐式调用。我所做的是创建一个方法来初始化它int[] iToken = initArray(); ... private int[] initArray() { String text = "200 300 250 150 400 100"; String[] token = text.split("\\W"); int[] itoken = new int[token.length]; int i = 0; for (String str : token) { itoken[i++] = Integer.parseInt(str); } return itoken; }
不要在顶级容器上绘画,例如
JFrame
。相反,我们是JPanel
或JCompoent
并覆盖paintComponent
,并覆盖getPreferredSize()
在你的JPanel
所以您不必设置JFrame
的大小。就pack()
它。从 Event Dispatch Thread 运行 Swing 应用程序像这样
public static void main(String[] args) { SwingUtilitiies.invokeLater(new Runnable(){ public void run(){ new Test(); } }); }
您永远不会将按钮添加到框架中。
不要使用空布局。使用Layout Managers .
添加组件,然后调用
setVisible
这是正在运行的重构代码
import javax.swing.*;
import java.awt.Graphics;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class Test extends JFrame implements ActionListener {
JButton button;
boolean paint = false;
int x, y;
int[] iToken = initArray();
public Test() {
super("Test");
button = new JButton("GO");
button.setBounds(500, 100, 50, 50);
button.addActionListener(this);
add(button, BorderLayout.SOUTH);
add(new DrawPanel());
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.pack();
this.setVisible(true);
this.setResizable(true);
}
public void actionPerformed(ActionEvent e) {
if (e.getSource() == button) {
paint = true;
repaint();
}
}
private int[] initArray() {
String text = "200 300 250 150 400 100";
String[] token = text.split("\\W");
int[] itoken = new int[token.length];
int i = 0;
for (String str : token) {
itoken[i++] = Integer.parseInt(str);
}
return itoken;
}
public class DrawPanel extends JPanel {
public void paintComponent(Graphics g) {
super.paintComponent(g);
if (paint) {
for (int i = 0; i < iToken.length; i += 2) {
x = iToken[i];
y = iToken[i + 1];
g.drawOval(x - 5, y - 5, 10, 10);
}
}
}
public Dimension getPreferredSize() {
return new Dimension(500, 500);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new Test();
}
});
}
}
关于java - 使用 Paint(g) 和 run() 绘制点,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/21431122/