本文介绍了程序不是绘画的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我打算为此在我的JPanel上画一个正方形,但是,它没有出现。
我在做什么错了?
class GUI扩展JPanel {
private static Game = new Game ();
...
public GUI(){
SwingUtilities.invokeLater(new Runnable(){
public void run(){
setAttributes();
makeMenu();
}
});
}
...
public void paintComponent(Graphics g){
super.paintComponent(g);
g.setColor(Color.white);
g.drawRect(20,20,100,100);
$ / code $ / pre
$ hr
编辑:代码
import javax.swing。*;
import java.awt。*;
import java.awt.event。*;
类GUI扩展JPanel {
private static Game = new Game();
private static JPanel panel = new JPanel();
private static JFrame frame = new JFrame();
final private static int FRAME_HEIGHT = 500;
final private static int FRAME_WIDTH = 500;
//开发板尺寸25x25px
final private int PIXEL_SIZE = 20;
public GUI(){
SwingUtilities.invokeLater(new Runnable(){
public void run(){
setAttributes();
makeMenu();
}
});
}
public static void setAttributes(){
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setTitle();
frame.setBackground(Color.black);
frame.setVisible(true);
private static void makeMenu(){
JButton start = new JButton(Start);
start.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
game.startGame();
}
});
panel.add(start);
frame.add(panel);
frame.pack();
}
public void setGameFrame(){
panel.removeAll();
frame.setTitle(Snake v0.1);
frame.setSize(FRAME_WIDTH,FRAME_HEIGHT);
}
public void paintComponent(Graphics g){
super.paintComponent(g);
g.setColor(Color.white);
g.drawRect(20,20,100,100);
}
public void paintGraphics(){
int [] [] pixels = Game.getGraphics();
}
}
解决方案 I看着你的代码。你在哪里添加GUI到任何东西?答:你没有,如果你不这样做,什么都不会画。解决方案:将它添加到gui中,并阅读教程,因为代码中有很多需要修复的地方。
其他建议:
- 删除所有静态变量,除了contants。
- 在主方法中调用invokeLater,而不是在JPanel的构造函数中调用
>
- 再次,将您的绘画图形用户界面添加到您的实际GUI中,以便将它添加到显示它的内容中。 不要调用
getGraphics()
,因为它会为你提供一个非持久化的Graphics对象。
例如,
import javax.swing。*;
import java.awt。*;
类GUI扩展JPanel {
private static final int PREF_W = 200;
private static final int PREF_H = PREF_W;
private static final int RECT_X = 20;
private static final int RECT_Y = RECT_X;
private static final int RECT_WIDTH = 100;
public GUI(){
setBackground(Color.darkGray);
}
//使用@Override确保你的方法是一个真正的覆盖
//注意paintComponent应该被保护,而不是public
@Override
protected void paintComponent(Graphics g){
super.paintComponent(g);
g.setColor(Color.white);
//在此避免魔术数字。
g.fillRect(RECT_X,RECT_Y,RECT_WIDTH,RECT_WIDTH);
g.setColor(Color.red);
g.drawRect(RECT_X,RECT_Y,RECT_WIDTH,RECT_WIDTH);
}
//以便布局管理员知道我想要这个JPanel有多大。
//这是一个愚蠢的方法实现。你希望更聪明
@Override
public Dimension getPreferredSize(){
return new Dimension(PREF_W,PREF_H);
private static void createAndShowGui(){
GUI mainPanel = new GUI();
JFrame frame = new JFrame(GUI);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane()。add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
public static void main(String [] args){
SwingUtilities.invokeLater(new Runnable(){
public void run(){
createAndShowGui();
}
});
}
}
I intended for this to paint a square on my JPanel, however, it does not show up.What am I doing wrong?
class GUI extends JPanel {
private static Game game = new Game();
...
public GUI () {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
setAttributes();
makeMenu();
}
});
}
...
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.white);
g.drawRect(20, 20, 100, 100);
}
}
Edit: the code
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class GUI extends JPanel {
private static Game game = new Game();
private static JPanel panel = new JPanel();
private static JFrame frame = new JFrame();
final private static int FRAME_HEIGHT = 500;
final private static int FRAME_WIDTH = 500;
//Board size 25x25px
final private static int PIXEL_SIZE = 20;
public GUI () {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
setAttributes();
makeMenu();
}
});
}
public static void setAttributes() {
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setTitle("");
frame.setBackground(Color.black);
frame.setVisible(true);
}
private static void makeMenu() {
JButton start = new JButton("Start");
start.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
game.startGame();
}
});
panel.add(start);
frame.add(panel);
frame.pack();
}
public void setGameFrame() {
panel.removeAll();
frame.setTitle("Snake v0.1");
frame.setSize(FRAME_WIDTH, FRAME_HEIGHT);
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.white);
g.drawRect(20, 20, 100, 100);
}
public void paintGraphics() {
int[][] pixels = Game.getGraphics();
}
}
解决方案 I looked at your code. Where do you ever add GUI to anything? Answer: you don't, and if you don't, nothing will be painted. Solution: add it to the gui, and read the tutorials as there is much to fix in your code.
Other suggestions:
- Get rid of all static variables except for the contants.
- Call your invokeLater in your main method, not in a JPanel's constructor
- Again, add your painting GUI to your actual gui so that it gets added to something that will display it.
- Don't call
getGraphics()
on any component as that will get you a non-persisting Graphics object.
e.g.,
import javax.swing.*;
import java.awt.*;
class GUI extends JPanel {
private static final int PREF_W = 200;
private static final int PREF_H = PREF_W;
private static final int RECT_X = 20;
private static final int RECT_Y = RECT_X;
private static final int RECT_WIDTH = 100;
public GUI() {
setBackground(Color.darkGray);
}
// use @Override to be sure that your method is a true override
// Note that paintComponent should be protected, not public
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.white);
// avoiding "magic" numbers here.
g.fillRect(RECT_X, RECT_Y, RECT_WIDTH, RECT_WIDTH);
g.setColor(Color.red);
g.drawRect(RECT_X, RECT_Y, RECT_WIDTH, RECT_WIDTH);
}
// so that the layout managers know how big I want this JPanel to be.
// this is a dumb method implementation. Yours will hopefully be smarter
@Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
private static void createAndShowGui() {
GUI mainPanel = new GUI();
JFrame frame = new JFrame("GUI");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
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