每次按下四个按钮中的一个按钮时，我都会尝试更改数字。
每次运行文件时图形都会发生变化，但是当按下按钮时我不知道如何更改它。
有没有一种方法我可以调用重绘StrokePanel或者我必须做其他事情吗？
这是到目前为止的代码
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.geom.*;
import javax.swing.border.LineBorder;
public class GeomtryQuiz extends JApplet{
boolean playing = true;
static int chosen = 0;
static boolean answer = false;
static boolean change = false;
public static void main(String[] args){
JFrame frame = new JFrame();
frame.setTitle("Geometry Quiz");
frame.setSize(1024,900);
frame.setBackground(Color.white);
JApplet applet = new GeomtryQuiz();
applet.init();
JButton[] buttons = new JButton[4];
buttons[0] = new JButton("Triangle");
buttons[1] = new JButton("Square");
buttons[2] = new JButton("Pentagon");
buttons[3] = new JButton("Hexagon");
frame.getContentPane().add(applet);
Container c = frame.getContentPane();
JPanel p = new JPanel();
p.setLayout(new GridLayout(2,2));
c.setLayout(new BorderLayout());
for(int i = 0 ; i < 4; i++){
buttons[i].setPreferredSize(new Dimension(70,70));
buttons[i].setBackground(Color.pink);
final JButton b = buttons[i];
final int angle = i;
final int n = 3;
b.addActionListener(
new ActionListener(){
public void actionPerformed(ActionEvent e){
if(b.isEnabled()){
control(angle);
}
if(!b.isEnabled()){
}
}
}
);
p.add(buttons[i]);
}
c.add(p,BorderLayout.SOUTH);
c.add(applet,BorderLayout.CENTER);
frame.setVisible(true);
}
public static void control(int i){
if((i + 3) == chosen){
JOptionPane.showMessageDialog(null,"Correct");
}
else{
JOptionPane.showMessageDialog(null,"Wrong");
}
change = true;
}
public void init() {
JPanel panel = new StrokePanel();
getContentPane().add(panel);
}
class StrokePanel extends JPanel {
public StrokePanel() {
setPreferredSize(new Dimension(1024,800));
setBackground(Color.white);
}
public void paintComponent(Graphics f){
Graphics2D g = (Graphics2D)f;
Point2D center = new Point2D.Float(512,250);
float radius = 1000;
float[] dist = {0.1f, 0.2f, 1.0f};
Color[] colors1 = {Color.white, Color.white, Color.red};
RadialGradientPaint p = new RadialGradientPaint(center, radius, dist, colors1);
g.setPaint(p);
g.fillRect(0,0,1024,800);
int random = (int)(Math.random()*4 + 3);
chosen = random;
drawShape(g,random);
}
public void drawShape(Graphics g,int numri_brinjeve)
{
Graphics2D g2 = (Graphics2D)g;
g2.setStroke(new BasicStroke(2.0f));
g.setColor(Color.pink);
g2.translate(512,250);
double kendi = 360.0/numri_brinjeve;
GeneralPath path = new GeneralPath();
double a = 0;
double c = 0;
double x = 0;
double y = 0;
double r = 150;
for(int i = 1 ; i <= numri_brinjeve + 1 ; i++) {
x = r* Math.cos(Math.toRadians(i*kendi));
y = r* Math.sin(Math.toRadians(i*kendi));
a = x;
c = -y;
if(i == 1)
path.moveTo(a, c);
// System.out.println(i + ", " + a + ", " + c + "," + i*kendi);
path.lineTo(a, c);
}
g2.fill(path);
g2.setColor(Color.lightGray);
Stroke stroke = new BasicStroke(7);
g2.setStroke(stroke);
g2.draw(path);
}
}
}
答案 0 :(得分：1)
每次按下四个按钮之一时，我都会尝试更改数字
您需要调用repaint来触发新的绘制周期
extends JApplet令人困惑。作为一般规则，您不应该自己创建和操作Applet，它们应该由浏览器插件管理。
基于你的代码，我看不出任何真正的理由拥有它，所以我首先要摆脱它。
现在，这将开始创建其他问题，突出显示您可能遇到的问题
//JApplet applet = new GeomtryQuiz();
//applet.init();
frame.getContentPane().add(applet);
//...
c.add(p, BorderLayout.SOUTH);
c.add(applet, BorderLayout.CENTER);
好的，首先将applet添加到内容窗格，但稍后再添加...？在这种情况下，这实际上是一个无操作，但可能导致问题没有结束，请确保您只添加一次组件
但这提出了下一个问题，即使用什么来代替小程序？好吧，因为applet唯一要做的就是向它添加StrokePanel，然后它很简单，只需使用StrokePanel而不是
这是事情变得更复杂的地方。
基本上，StrokePanel需要保持其当前状态，因此chosen实际上应该是StrokePanel的属性，chosen 也不应该< / strong>在paintComponent内进行修改，这将导致问题无法解决，因为paintComponent可以随时出于任何原因被调用，大多数情况下没有您的参与。所以，相反，你需要一些方法来设置和获得该值
StrokePanel class StrokePanel extends JPanel {
private int chosen = 0;
public StrokePanel() {
setPreferredSize(new Dimension(1024, 800));
setBackground(Color.white);
}
public int getChosen() {
return chosen;
}
public void setChosen(int chosen) {
this.chosen = chosen;
repaint();
}
@Override
protected void paintComponent(Graphics f) {
super.paintComponent(f);
Graphics2D g = (Graphics2D) f;
Point2D center = new Point2D.Float(512, 250);
float radius = 1000;
float[] dist = {0.1f, 0.2f, 1.0f};
Color[] colors1 = {Color.white, Color.white, Color.red};
RadialGradientPaint p = new RadialGradientPaint(center, radius, dist, colors1);
g.setPaint(p);
g.fillRect(0, 0, 1024, 800);
drawShape(g, getChosen());
}
public void drawShape(Graphics g, int numri_brinjeve) {
Graphics2D g2 = (Graphics2D) g;
g2.setStroke(new BasicStroke(2.0f));
g.setColor(Color.pink);
g2.translate(512, 250);
double kendi = 360.0 / numri_brinjeve;
GeneralPath path = new GeneralPath();
double a = 0;
double c = 0;
double x = 0;
double y = 0;
double r = 150;
for (int i = 1; i <= numri_brinjeve + 1; i++) {
x = r * Math.cos(Math.toRadians(i * kendi));
y = r * Math.sin(Math.toRadians(i * kendi));
a = x;
c = -y;
if (i == 1) {
path.moveTo(a, c);
}
// System.out.println(i + ", " + a + ", " + c + "," + i*kendi);
path.lineTo(a, c);
}
g2.fill(path);
g2.setColor(Color.lightGray);
Stroke stroke = new BasicStroke(7);
g2.setStroke(stroke);
g2.draw(path);
}
}
GeomtryQuiz 我没有对此进行一些重复，主要是，我删除了JApplet并将核心应用程序移出static上下文（宠物讨厌）。
主要更新是包含update方法，该方法生成随机形状并更新StrokePanel
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
public class GeomtryQuiz {
boolean playing = true;
boolean answer = false;
boolean change = false;
private StrokePanel strokePanel;
public static void main(String[] args) {
new GeomtryQuiz();
}
public GeomtryQuiz() {
JFrame frame = new JFrame();
frame.setTitle("Geometry Quiz");
frame.setSize(1024, 900);
frame.setBackground(Color.white);
JButton[] buttons = new JButton[4];
buttons[0] = new JButton("Triangle");
buttons[1] = new JButton("Square");
buttons[2] = new JButton("Pentagon");
buttons[3] = new JButton("Hexagon");
Container c = frame.getContentPane();
JPanel p = new JPanel();
p.setLayout(new GridLayout(2, 2));
for (int i = 0; i < 4; i++) {
buttons[i].setPreferredSize(new Dimension(70, 70));
buttons[i].setBackground(Color.pink);
final JButton b = buttons[i];
final int angle = i;
final int n = 3;
b.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
if (b.isEnabled()) {
control(angle);
}
if (!b.isEnabled()) {
}
}
});
p.add(buttons[i]);
}
c.add(p, BorderLayout.SOUTH);
strokePanel = new StrokePanel();
c.add(strokePanel, BorderLayout.CENTER);
update();
frame.setVisible(true);
}
protected void update() {
int last = strokePanel.getShape();
int random = last;
do {
random = (int) (Math.random() * 4 + 3);
} while (random != last);
strokePanel.setShape(random);
}
public void control(int i) {
if ((i + 3) == strokePanel.getShape()) {
JOptionPane.showMessageDialog(null, "Correct");
update();
} else {
JOptionPane.showMessageDialog(null, "Wrong");
}
change = true;
}
}